Sete Cidades photo by Pawel Prokocki
Part 2: The Volcanoes
In this part we are touring the volcanoes of São Miguel. I wanted to write a good tour post on these and as told in part one it is meant as an accompany that you read on your phone when you are visiting the island. São Miguel Island consists of six major volcanic zones that we will tour from east with Nordeste as starting point, to west where we finish the tour at Sete Cidades. You can imagine travelling by rental car doing this journey along the island’s length. I will talk about the large scale sights and main attractions that each locale stop provides. There is enough to see here so I cannot cover everything.
The Nordeste volcano
Upper photo: Google Earth, Lower photo: Michael Mehl. Nordeste massifs seen from Povacao caldera
After the hotel check-in I took the rental car and drove east as far as you can get, to the oldest part of the island, Nordeste – ”northeast” in English translation. It is the oldest volcano on the entire island and is heavily eroded by the heavy rains. It is a ruin of what was once a fissure shield volcano that rose high above its surroundings, very likely much taller and broader than it is today. Its peak, Pico da Vara thrusts into gloomy cloud blankets that cover most of the stunning greenery on this island. The warm wet subtropical lowlands contrast with the cooler peak, but the peak is still much too warm for snow. At the coast, Ponta Sorgesso provides a spectacular viewpoint out over the Atlantic and the steep sea cliffs that drop into the deep blue waves.
Nordeste is a heavily eroded pile of thin mildly alkaline lava flows 1300 m thick and dated to the Pliocene era, 4,01 million years old for the lower lava flows. Lava flows higher in the pile are more potassic than the lower stack member of the pile. Some other datings give a much younger age for the lower lava sequence. Nordeste has no obvious volcanic features on the ground. It is heavily eroded and lava flows are only visible in road cuts, as is the case of most of the Island, but in Nordeste you don’t even find cinder cones. Nordeste is basically a pile of fissure-fed thin Aa flows and there are no signs of major trachytic productivity other than minor exposures. In its youth, it may have resembled Marion Island combined with Hekla (minus Heklas evolved magmas). It would have been a fissure eruption shield volcano dotted with past cinder cones, by now it is highly eroded, cut by younger calderas and landslides and river streams drape the scenery. There are arguments for the pliocene datings from other sites, with genetic studies of the islands land snails that diverged around 4 to 3 million years ago that will support pliocene datings on lava rocks.
Nordeste offers little in terms of visible volcanic features and the coast scenery is the main attraction so I drove west again to the Povocao volcano. There is no clear evidence of a past caldera at Nordeste. Nordeste may never erupt again; it seems pretty extinct.
The Povoação volcano
Photos: Google Earth the immense Povoação caldera which borders with Furnas and Nordeste volcanoes
Driving west from Nordeste the lush landscape opens up towards the spectacular Povoação volcanic complex whose enormous caldera has carved out large parts from the Nordeste’s old shield. The feature measures seven kilometers wide and the caldera wall borders with the Furnas and Nordeste complexes to the west and east. The scenery is spectacular and reminded me of a subtropical version of UK farmlands or North New Zealand’s countryside, very pleasant with small towns and groves. Like Nordeste, Povoação is a very old and extremely tired volcano who has not erupted for a very long time. You don’t find any hot springs or geothermal mudpots here unlike the island’s more westerly volcanoes that have lots of geothermal features. It kind of looks like a landslide, but Povoação does have tectonic fault features of a true caldera, so it is not an erosional or landslide feature.
There are four post caldera extrusive features in Povoação that have been mapped by geologists. one trachyte coulee ( thick stubby flow) and three alkaline scoria cones have been mapped, suggesting that the magma system remained alive after the collapse. Povoação’s floor is gentle and without much terrain other than river valleys. The caldera has lots of trachytic pumice in its soil deposits, not from the caldera itself but trachytic tephra airfall from the nearby Furnas volcano to the west which is a much more active caldera for sure. At the northern rim of Povoação there are 100 m thick trachytic pumice deposits that predate the caldera formation with more than one or two layers responsible for the Povoação caldera collapse itself. At the village of Povoação, steep cliffs drop into the ocean. Povoação offers relatively little volcanic features compared to the other São Miguel volcanoes. The eruption that formed the caldera was enormous and laid waste to wast areas a long time ago. Povoação may erupt again sometime in the far future, but seems pretty dead for now.
The dangerous Furnas volcano
Photo: Google Earth and https://azoresgetaways.com/en-us/destination/azores/islands/sao-miguel/furnas-village Furnas caldera is one of the most beautiful and most dangerous volcanoes in the entire Azores island group. Lower photo is an unusually clear day often is cloudy
Driving towards Povoaçãos western rim the road climbs into the mountains. At the caldera wall of Povoação you enter another magnificent caldera volcano. Furnas is one of the most dangerous volcanoes on the entire island and it is also one of the most beautiful. It is home to lush forests, a magical lake, geothermal springs, geothermal baths, small towns and a botanical garden. For me it was one of the most beautiful sights that I have ever visited. Furnas caldera is little like a lost world, almost like Jurassic Park or something like that. It is an isolated sheltered world deep inside the caldera, its own little society inside this volcano that has an immense peaceful scenery and atmosphere.
Furnas is often cloudy and mists hang over it and inside it. It adds an otherworldly feel where grey clouds hug subtropical forests that grow in the caldera walls and where huge cryptomeria trees giants rise over the mysterious mist layers. Tree ferns, moss, palms and the huge conifers add a ” Jurassic” feel to Furnas, perhaps not unlike Kilauea’s fern-filled summit area, but here the volcanic landscapes are much more developed by man with agricultural fields and small towns. Despite that it feels very primordial. Primordial for sure, especially so during a cloudy day, when everything here becomes extra green and extra mysterious. The rainforested caldera walls where waterfalls stream down, ferns cling to rocks and the crater lake, often having a low cloud ceiling where drooping tree branches hang over emerald green lilly pad-filled waters, were extra surreal for me. It is a place for meditation and thinking and indeed a neogothic church was built long ago at the volcanic lake shore side. The beaches you find in all the island’s caldera lakes are beige due to the trachyte materials. Furnas together with Sete Cidades, while not my geological highpoints in terms of volcanoes, are still among the most beautiful places that I have ever visited. That is because of their private ”lost world” atmosphere and spooky lush greenery and especially so for Furnas geothermal steam. I spent a lot of time there with friends exploring all the geothermal features and we ate the volcano-cooked local foods.
Furnas unlike Povoação and Nordeste does have a real, alive-and-kicking magma system which remains active even if magma supply is slow. Geothermal activity is everywhere, hot water pools, mudpots and mineral-rich springs can be found. In the center of town, Furnas boasts close to 30 bubbling geothermal features some of which are boiling hot, their steam plumes dragging in the mists add to the mysterious otherworldly, slightly unsettling atmosphere that exists here. There are numerous geothermal baths too, all having warm brown iron oxide rich waters. All of these baths are artificially built but use warm volcanic waters from the magma system. Terra Nostra is the largest bath in Furnas: it can house hundreds of guests. I swam in it briefly. I liked the heat but the water quality seemed like a mudpool, even if it was in reality very clean stuff just with rust in it. Geothermal activity in Furnas can be found both in Furnas-village and on the lake shore where there is another set of hot mudpots with mud so fine it seems like paint. The locals boil some of their foods in these hot holes which are then served at fine dinners. The plentiful geothermal steam is a cruel reminder that 1439 persons live inside a timebomb. The last eruption in the year 1630 was as large as St Helens, 1980. 1 km3, and around 200 persons were killed. Previous eruptions here dwarfed the 1630 event. Eruptions in Furnas caldera are of a highly explosive evolved type. The eruptions are plinian, subplinian, vulcanian, phreatomagmatic; lava domes are often formed in the end. The volcano vents constantly produce CO2 gases that collect in deep lying areas. Many homes have gas alarms in case concentrations get too high. A description of Furnas chronology follows below.
Upper photo; Michael Runkel, lower photo Tiffany, lush scenery near the caldera wall of Furnas
Furnas is a nested evolved caldera structure that has collapsed numerous times. It is almost 8 kilometers wide and many 100s of meters deep. There have been major Pleistocene explosive eruptions here, some of these vastly larger than the most recent explosive eruptions. Post caldera eruptions been smaller pyroclastic events (if the 1630 event can even be called ”small”). All of the magmas are sourced from an evolving shallow large trachytic magma body that is compositionally zoned. In many studies, the violent history of Furnas is seen in the abundance of light pumice and grey ash in outcrops. Eruptions outside the caldera are mafic. Furnas, unlike the other volcanoes to east, has well studied history, even if geochronology is hard for all volcanoes in the greenery of São Miguel.
Furnas, like Agua De Pau and Sete Cidades, is an excellent example of the evolution of a mature Azores volcano from a fluid mafic one to evolved caldera volcanism. Furnas began its life on the seafloor as a slowly active alkaline mafic shield in the Pleistocene, 800,000 years ago, later emerging above sea. Furnas is today a sillicic nested caldera structure. The oldest and largest outer caldera likely signaled the change to trachytic caldera volcanism. The Pleistocene was plagued with sillicic caldera forming events at Furnas. The largest each happened after 1000 s or even 10,000 s of years of dormancy. The older caldera was an enormous event (Tambora sized in collapse area but volume is unknown ) The second large inner caldera collapse, four km wide dates back to the Povoação Ignimbrite that happened 30,000 years ago, when the Furnas volcano had its most recent major caldera collapse. The eruption was enormous and massive pyroclastic flows engulfed everything laying down ignimbrites in valleys. The pyroclastic flows also flowed into Povoação caldera giving this Furnas eruption the name of the wrong volcano even. Around 11,000 years ago there was another enormous pyroclastic eruption that collapsed the inner caldera once again, but smaller than the earlier two.
After the last large caldera collapse the volcano stratography becomes a bit better known with tephra zones from many series of trachytic eruptions. In the last 5000 years there have been 10 smaller trachytic eruptions from Furnas that have laid down their pumice airfall in the caldera. The Furnas C eruption was the largest of the group of later eruptions and dates to 1900 years ago. A 2 km wide collapse feature formed where Furnas town now sits; carbonized ”fossil” leaves have been found in ash from this event..
Since humans came to the Island there have been two plinian eruptions in Furnas, in the years 1439 and 1630. Both ended with a lava dome extrusion as the final gas-poor stuff came up. The 1630 event occured when the caldera was nearly as densely populated as today. It was known as the “Year of the Ashtray” it was disastrous with 200 persons were killed in the eruption with ash and destruction spreading over vast areas.
If we take 5000 years divided by 10 eruptions gives an eruption once every 500 years, but there is no timetable for that. Eruptions at Furnas are very likely caused by injection of a more mafic mugearite or hawaiitic magma into Furnas trachytic magma chamber. Furnas will erupt again and in geological times likely soon. Any new eruption poses a lethal threat to all of the caldera residents who seem to have formed a friendly relationship with the time bomb they are living in. In short, Furnas is a mature Azorian central volcano. It has evolved a silicic heart and has a long history of repeated collapse and refill.
photo by Erika
The Congro Fissural system
The Congro Fissural System
Driving west from the Furnas caldera I entered the first monogenetic field on the Island on our tour from east to west. CVFS Congro Fissural Volcanic System is a series of cinder cones between the Furnas and Auga De Pau central volcanoes. The eruptions here are one go and then erupt elsewhere, caused by numerous small magma pockets. Some monogenetic eruptions here are fully trachytic like Lagoa do Congro an indication that there are many melt pockets here, some which are in an advanced state of fractional evolution. Most cones are less evolved magma and the whole landscape echoes Chaîne des Puys but the climate is even milder and huge cryptomeria trees dot many of the cinder cones. The landscape is as beautiful as it is everywhere on the island, with cow pastures and tree filled cinder cones.
One of the most magical sights in the monogenetic Vulcânico Fissural do Congro field are the hidden forest lakes that you can find inside numerous cinder cones and one such lake in a maar crater. Just as in the Furnas and Sete Cidades lakes it is a private enclosed and slightly mysterious atmosphere where subtropical forests drop into green anoxic looking waters. The easiest of these hidden gems is Lagoa do Congro (lagoon) which occupies the base of an explosion maar crater maar. It is 500 metres of diameter, with steep walls emplaced in basalts and trachytes and a maximum elevation difference of approximately 120 metres. This crater, formed about 3800 years ago, is associated with a hydromagmatic eruption. There is even a trail to it and you walk along laurel and cryptomeria rainforest on the way down to its shores. There are three other monogenetic cinder cones that have such magic lakes here, but they have no trails up to them. One is named Lagoa do Arieiro, which is another very peaceful place where misty forests loom over a lonely cone lake. One of these other cones just north of Lagoa do Congro is likely almost never visited by any tourists. Another similar one is found just west of the Congro maar but seems more accessible.
The area seems dead silent with only birds song and wind, but in 2005 and 2011 – 2012 there was intense seismicity and some ground deformation an indication of magma rising and stalling at shallow levels in the crust. The area has been quite active in the Holocene, but it is nowhere near as large as the Pico’s fissural monogenetic system close to the main city, where you find 100 s of cinder cones (well green as always). An interesting note is that CVFS is one of the most seismically active regions on the entire island.
The dangerous Auga De Pau volcano
Lower Photo: Kiko Jimenez, upper photo Google Earth
Driving west from Congros monogenetic cones, I came up into more hilly terrain and a gentle slope was right ahead, a huge cloud cumulus castle hovered right ahead in the highlands. The massif right ahead was the Agua De Pau stratovolcano, the tallest active stratovolcano on the entire island. The volcano is, just like Furnas, dangerous for the local populations which face threats both from pyroclastic flows, tephra falls, and even fast-moving lava flows, due to its bimodal nature, meaning it has erupted both mafic and sillicic magmas before. Since the island was settled, two eruption events have caused problems for villagers.
Agua De Pau is hardly a magnificent stratovolcano like Etna or Fuji, it is lumpy and its summit is strongly eroded by the subtropical rains in these latitudes. Auga De Pau’s lumpy upper parts are a combination of factors of erosional rainfall in pyroclastic deposits and all trachytic lava domes and coulees (short stubby viscous lava flows ) that have been extruded around the nested caldera complexes. The road upwards to the summit snakes through the eroded trachytic domes. The summit crater provides the Lagoa do Fogo lake, one of the 3 caldera lakes on the island and its highest.
Much of the land surrounding the crater lake is occupied by large parcels of median 283 hectares (2,830,000m2) in size, 61 hectares (610,000m2) of forested cover and endemic Macronesian Azorian species. Among that is the everpresent japanese cryptomeria trees that dot the grey trachytic pumice beaches. The caldera lake was formed 15 000 years ago and that was the last really large eruption, but there been numerous trachytic explosive eruptions since that. The last one in 1563 erupted one km3 of trachytic materials.The caldera also contains very eroded pumice cones and remains of lava domes. Agua De Pau, like Furnas and Sete Cidades, is an excellent example of a mature Azorian central volcano that have developed a sillicic central magma system and bimodal flank eruptions.
This volcano has like furnas a strong geothermal activity and hot baths and springs can be found in the jungles on its flanks. Caldeira Velha (thermal baths ) have wonderful jungle trail and hot baths. A geothermal power plant can also be found on the volcano’s north slope. Agua De Pau shows the typical evolution of an Azorian central volcano from basaltic to silicic magmas.
Auga De Pau has a long and studied history. It began to grow 200,000 years ago as a basaltic shield or basaltic stratovolcano that grew out of the ocean, during this time São Miguel was not one island but perhaps a series of islands. The oldest basaltic rocks in this region have an absolute age >250 ka – most of them were formed in a submarine environment. The volcano then grew and grew forming a tall structure that rose above the sea. The oldest materials from this volcano in cores are about 280,000 years old and consist of alkaline basalt trachybasalt lavas. The volcano later developed into a evolved explosive stratovolcano with bimodal flank behavior. The volcano is draped with tephra and pyroclastic deposits and tephra chronology have been done on available outcrops. The volcano has a long history of explosive tephra rich eruptions, that have draped the edifice in deposits. Some events will be very briefly described here.
Since 40 000 years back the volcano’s eruptive history is much better understood with many layers of trachytic pumice materials emplaced from pyroclastic currents that have formed a series of dated formations. The Porto Formoso sequence is a series of pyroclastic deposits dated to 21,000 years back from a series of trachytic events; ignimbrites with fiamme stones can be found in road cuts. Another eruption formation is the Cha Gatas sequence that forms a whole series of pumice flows and ignimbrites some with syenitic xenoliths in that outcrop. (Syenite is the plutonic version of trachyte.) The Coroa eruption is another one which laid down a single trachytic formation dated to 18,000 years ago. In its later phases it formed a pumice cone and dome visible 2.5 km south east of the Ribeirnha village. Obsidian fragments and coarse pumice blocks can be found in abundance in this deposit in exposures. Roida da Praia formation is an impressive formation almost 100 meters thick in roadcuts from Agua De Pau. Rodia is the product from a group of 65 explosive trachyte eruptions. Five of these eruptions were very large. The older member eruptions have a lot of light coloured pumice and lapilli from subplinian activity which is dated to 34,000 years ago. The middle member of eruption groups is dated 14,000 years ago and has darker materials than the older unit. Lapilli and pumice are mixed with syenitic mantle xenoliths like in earlier deposits.
The Ribeira Cha eruption formation is a particularly spectacular one, from a very violent short-lived eruption that has been dated around 12,000 years ago. Other dating methods yields up to 16,000 years ago for the formation. Syenitic xenoliths (plutonic magma pieces) are common in this deposit too. The ignimbrites from this eruption show many deposits from the same eruption repeated pyroclastic flows. Ribeira Cha is generally agreed to be the culprit behind the larger outer summit caldera formation. The Ribeira Cha eruption is overlaid by smaller deposits from the Pisao formation that contains bubble rich lapilli and pumice stones. The Fogo A eruption overlies this and is one of the most studied in the island. The eruption was very violent and laplli pumice rained down over the entire island and the layer is the best age key in stratography because of that. Another younger unit above that is Lombadas formation that spans 3000 years with three eruption events over that time.
The last major eruption from Agua De Pau was on 28 June 1563 and that was witnessed by the locals. It had a very interesting explosive first plinian trachytic phase in the summit. The 1563 eruption was on the northwest interior flank of the summit caldera and took place after days of tremor in the surrounding towns. It likely started with a loud phreatomagmatic detonation. The Fogo 1563 plinian eruption formed a set of more than 70 stratigraphic sections were documented, allowing to establish eruption layer correlations and to understand the internal structure of the deposit. The 1563 eruption layers is characterized by alternating ash and pumice lapilli layers and it was possible to discriminate two deposits defined by their dominant lithofacies and stratigraphic position, which are representative of two eruption phases. Eyewitnesses reported late at night June 28 1563 an intense glow over the summit and thunderous booms that would be the hot base of a plinian column. During the first night, grey lapilli and pumice fell on the eastern and northeastern parts of the Island. By the 29 June changes in wind directions meant that ash began to fell on Ponta Del Gada leaving a 10-centimeter thick layer.
Photo: Stromboli Online website: the 1563 lava flow buried the whole town Ribeira Seca under fast-moving lava, a fountain can be found half-buried, while the new town was later built on top. Today 100 s of years later pretty much no fresh surfaces of the lava flow can be found.
Four days after the trachytic eruption stopped, on 3 July there was a final very interesting effusive flank event caused by fluid basalt emerging from the deeper parts of Aguas plumbing system. Fast-moving Nyiragongo-like mafic lava burst out at Pico Do Sapatiero, an older trachytic dome through the western tectonic fault, and very fluid lavas rushed down the slope towards the villages below. The locals saw a column of steam and a mean glow litting it up, and reading from accounts from diffuse sources. A fast-moving lava stream ran straight trough the Ribeira Seca settlement where it crashed into the ocean waves. The priest Gaspar Frutuoso wrote down the event as did others,in the ”Phoenix of Angra” Fénix Angrense account. The lava was described as very thin and fluid and flowing like a river in flood, a good sign that it was from deep and primitive materials. Some of these lava flows contain both alkaline basalt and pieces of evolved trachytic materials, a clear sign of magma mixing in the central volcanoes, in a magma system with a zoned composition.
Picos Fissural System
Picos
Driving west from Augua De Pau’s eroded pyroclastic hills and trachytic domes, the landscape opens up as you heads down its slope towards the next volcano Sete Cidades. On the way to Sete Cidades you are driving through the youngest part of the entire island, the Picos Fissural system. It is named Picos Volcanic Fissural System and it is the largest monogenetic field on São Miguel. Here you visit more than 200 cinder/scoria cones which dot the landscape and are beautifully green. It’s a beautiful green landscape with lush gardens, pastoral fields, hedges and flower gardens and small towns. Some cinder cones are covered with small subtropical rainforests, others are crop fields with intense blue hydrangea hedges making interesting patterns with the green pastures and crop fields.
Picos Volcanic Fissural System is young, the most recent addition to the island. Before its formation Sete Cidades and Agua De Pau volcanoes were not joined. The whole region is young and I saw almost no signs at all of erosional valleys or rivers. Still eruptions are infrequent enough to allow the subtropical greenery to flood everything leaving no fresh barren lava surfaces. Monogenetic cones are everywhere here, some are half crescent shapes while some others are true cinder, scoria cones. The geological youth is also shown by the coasts not having very steep cliffs, with frequent lava flows called Fajãs ”lava shelfs” extent out in the water making it easy for boats to make landfall. These were almost definitely the cause of why Ponta Del Gada was built in this part of the island. Picos Fissural system is young and compared to the rest of the island is very active. Any new monogenetic eruptions could cause mayhem in this densely populated area. Most messy woud be a fissure eruption upslope of Ponta del Gada sending Aa lava flows steaming through the city.
The Picos fissural system has been estimated to have emerged from the ocean around 30,000 years ago with monogenetic eruptions using tectonics faults, forming cinder cones along fault lines in the crust. Eruptions have been more frequent along the middle of this fault system, forming a distinct ”spine” where the cinder cones been heaped up. More than 270 scoria cones have been mapped in PFVS, they are so abundant that the landscape is almost saturated, they also have buried each other under a thicker and thicker pile. At Miradouro da Reserva Florestal de Recreio do Pinhal da Paz its possible to peek out over this cone filled young landscape. Over the past 5,000 years there have been 19 monogenetic eruptions and that gives an average of one cone forming eruption every 260 years in this region. There may seem to be few other volcanic features to see here, but below the surface there are lava caves scattered about, as is often the case with basaltic volcanism and near Ponta De Gada you can visit Gruta do Carvão lava tube system. The largest lava tunnel on the island of São Miguel. The cave is located on the western edge of Ponta Delgada and extends for 1,650 metres, I visited it last in May 2023. It exceeds expectations with well formed fluidal features and staligmites and well preserved surfaces. The last eruption here lasted from 19 to 26 October 1652 and broke out north east of Ponta Del Gada. It was rare for this area, being an evolved eruption with very tall fountains and explosive likely vulcanian detonations building up cinder cones. Two viscous short almost ”pancake” like dome-like lava flows were also emplaced. Today the eruption site is a forested hill. The eruption was seen by locals who described it in writings as a dark cloud of ash and hot black stones being thrown high in the day skies. The night scene was described as a fire with shooting fireballs going up into the night skies.
Sete Cidades volcano
Photos: google earth, Ivankyryk lush scenery inside the Sete Cidades caldera
The last volcano on our tour is also the most famous and scenic one on the entire island. Sete Cidades at the western point is one of the most spectacular sights on this island and is a major reason tourists visit São Miguel to hike its awe striking caldera landscape. I had the huge luck of being able to visit this collapsed bimodal stratovolcano just a few years ago. Sete Cidades rivals Furnas in terms of scenery and beauty. Both calderas can be called comparable in natural beauty, but Sete Cidades maybe could be called more scenic and its caldera walls are much sharper than Furnas and Aguas due to young age. This is the youngest central volcano on the island so has the sharpest features and sharpest edifice.
This is one of the worlds best examples of an explosive caldera that can be visited and be walked inside, although the green framework shows it is certainly not frequently active. Sete Cidades edifice is visible as a shield-like bulge if seen from Picos or Agua’s summits on a clear day. Visiting the caldera was a spectacular sight for me. It is an area that evokes awe and also a soothing calm. It is a captivating landscape that is perfect for an explorer who wants to take a long hike and return to same starting spot. There are many trails here one around the caldera rim and many paths to stroll in its lush interior. This is its own little world just like Furnas that is kind of enclosed and hidden away from outside by the caldera walls around. I found this green subtropical caldera immensely peaceful where the subtropical forests crowd the caldera walls and interior pumice cones and where their lush greenery hangs over mystical lake shores of Lagoa Verde and Lagoa Azul thats two peaceful (if slightly overfertilized lakes) that can be found in the caldera. When seen from up at the caldera rim the two lakes can under ideal light conditions get two colors, one green and one blue, lagoa verde and azul, and this is one of the most photographed spots in the caldera. Photographers often add extra saturation and sell them to media advert sites, but on closeup inspection lagoa azul appears just as green and mucky as lagoa verde: the cattle pastures are a source of too much fertilizer. The two lakes are connected but a scenic bridge runs over their narrow connection.
There are four lakes in the caldera. The other two can be found in a very large pumice cone complex, lagoa santiago and lagoa rasa. The caldera rim is often windy and breezy yet it is not cold. The subtropics make a great place to run around in it, which you cannot do in warmer places without overheating. When you hike down into the caldera’s interior after having done the caldera ring road, you are greeted with a scenery that exceeds expectations. I myself found it lush and scenic, scenic pastures and small villages mix with subtropical forests and the trachyte beaches provide scenic views over the lakes. It is a peaceful scenery and during cloudy days with mists, it becomes just as mysterious as Furnas to walk these lake shores during a misty day. The lush subtropical forests rise into misty caldera walls and tree branches hang over mysterious green waters. The caldera floor feels humid and hot compared to the cooler windy caldera edge which was noticeable when I did my hike. Observing it from the shore of the lake, the surrounding caldera looked like a giant green football stadium. The caldera has four enormous post intra caldera trachytic pumice cones whose postcaldera growth has filled the eastern and southern part of the caldera. The pumice cones are named Caldeira Seca, Caldeira do Alferes and Caldeira Santiago, with the last having two smaller freshwater lakes. It’s a serene place where you can stroll the beaches and the cones through the numerous hiking paths that are often lined with blue hydrangeas.
Between Caldeira Seca and Caldeira do Alferes pumice cones is the town with same name of the volcano. I spent quite some time walking its streets which were just as peaceful as those in Furnas. Here man has carved himself a peaceful pastoral existence inside a time bomb. Today almost 800 persons call the caldera home. The beautiful neogothic church of São Nicolau can be explored when you walk around the town. In such a green lush place there may seem to be no evidence of any recent volcanic activity, but the lake beaches have grey sand that turn out to be pumice and the hiking trails and sandy outcrops are littered with trachytic pumice stones. Other more clear signs of ongoing deep volcanic activity at Sete Cidades can be seen if you drive to Ponta da Ferraria tidal hot springs at the volcano’s south west coast. Here geothermal hot water wells up in a bay where you can swim in warm tidal waters that are heated by magma. Close to the geothermal pools is Pico Das Camarinhas, a very nice mafic scoria cone whose viscous looking Aa has formed a little lava delta that can be explored. Interaction between hot lava and seawater has also formed a well formed littoral pseudocone that is one of the best preserved examples on Earth. Such features don’t last very long so this one is an exceptional preservation 100 of years after the eruption.
Sete Cidades just like the other central volcanoes on São Miguel began to grow on the seafloor as a basaltic shield volcano, later evolving into a bimodal caldera. It began to grow before the Picos fissural system emerged. The start of construction of the submarine edifice is not known but its thought to be many 100 000 s of years ago, although it is not as old as the other volcanoes on the island. Sete Cidades emerged roughly 210 000 years ago from the sea as a separate island. Since then the complex above water has grown to about 70 km3. Doing some simple maths 70km3 in 210 000 years that gives us an estimated rate of 0.02–0.03 cubic kilometres (0.0048–0.0072 cu mi) per century, so 20 to 30 million cubic meters of erupted materials per 100 years, which is a lot less than than Hawaii that may do 10000 – 15000 million cubic meters per 100 years. Still the supply is certainly enough for one or two eruptions per century. Eruptions here since settlement have happened on submarine flanks, the Sabrina ephemeral island 1811 being a famous example. Sete Cidades have a long history of both trachytic and basaltic eruptions, flanks mostly produce mafic eruptions making mafic scoria cones, while the trachytic caldera produce explosive pyroclastic eruptions whose pyroclastic flows and tephra falls have laid down pale lapilli and pumice over the entire peninsula, seen in cliff exposures at the coast. The caldera has had no historical eruptions since people came to the island.
The volcano’s chronology for the past 36,000 years has become better known. The Risco formation consists of well-preserved pyroclastic flow deposits and can be found as meter-thick deposits around the coast. It consists of many members as units and some have well-developed charcoal deposits in them. It has been dated to around 35,000 years old. Above that is the slightly younger Ajuda formation that has been dated to around 28,000 years old. That is in turn overlaid by the massive Bretanaha Formation that covers the entire volcano and reaches 6 meters thick at the volcano caldera rim. Pyroclastic flows raced all over and carbonized forest remains have been dated to around 28750 years. The lower layer consists of yellow pumice and fine lapilli, the upper layers consist of block and ash flow deposits. Some of the ash flows were so hot that they almost behaved like lava flows after being deposited. That is in turn overlaid by the much younger Lombas Formation which happened 15,750 years ago, so 13 ka after the Bretanaha tephras. It consists of 12 eruption units of mostly pumice fallout. Not all of these are trachytic, some eruptions were mafic.
One of the most significant pyroclastic formation deposits at Sete Cidades is the Santa Barbara formation, that has a three step chronology. Pyroclastic flows raced down the edifice laying down hot deposits and some of these have fossilized carbonized tree trunks in them. The caldera itself has formed through repeated collapses in the late Pleistocence. After the last Ice Age ended the Sete Cidades caldera had assembled its current form after numerous explosive caldera ”re collapses” that laid down all these trachytic deposits. The present caldera developed in three phases associated with massive paroxysmal eruptions which occurred approximately 36,000, 29,000 and 16,000 years before the present. Post caldera activity are associated with more trachytic tephra layers, such as formation of the large pumice cones in it. In the last 5000 years there have been 17 smaller trachytic eruptions inside the caldera laying down pumice and lapilli. Many deposits have hydromagmatic features. In the same time span there have also been 15 radial, rift alkaline basaltic eruptions on Sete Cidades flanks. These eruptions happened as either mafic monogenetic cone forming, evolved dome forming events, forming cinder cones and domes on Sete Cuidades flanks. Many monogenetic flank eruptions where also submarine, some forming tuff cones leaving behind palagonized cone remains offshore.
If we do the maths 15+17 = 32 thats thirty two eruptions in 5,000 years so once every 156 years for Sete Cidades. There is no timetable and the evolved caldera has not been active since 500 A.D when the Seca pumice cone formed. The last eruption that was well documented on Sete Cidades happened in 1811 offshore in the sea, when a mafic flank eruption burst the ocean surface forming a temporary island that grew. The newborn island was given the name Sabrina Island. The first person to land on the island was commander James Tillard, captain of the British warship HMS Sabrina, who hoisted the Union Jack on the erupting island and claimed sovereignty for Great Britain. Tillard’s great discovery was to be short lived, the islet made of loose tephras was soon washed away by the sea.
The lost sabrina Island formed by the 1811 flank eruption of Sete Cidades. Source wikipedia
Sete Cidades is the youngest and historically (in terms of geology) the most active volcano on the island. It is possible or even likely that it will erupt during our lifetime. A very likely eruption scenario is a flank eruption that happens offshore in the sea. Most of these likely only form warm water plumes and discoloured seawater. The larger ones in shallower waters break the waves forming Surtseyan eruptions and short lived tuff islands. Even larger eruptions offshore may form Surtsey-like islands leaving behind palagonized islands and lava towers sticking up from the blue. An ocean eruption would be a good tourist eruption. A flank eruption on land woud be more problematic and would perhaps resemble Canaries eruptions. Sete Cidades is densely cultivated and small towns are everywhere. A flank eruption will destroy roads and homes and fields and the area won’t be usable for agriculture for well over 100 years due to loss of soil.
The flank eruptions can have numerous compositions. Flank eruptions of alkaline basalt will form fluid Hawaiian style eruptions with fast moving lava flows causing material damage. Slightly more evolved lavas (trachybasalt) may form strombolian eruptions and more slow ”basaltic” flows. A flank eruption of trachyte could either form a pumice cone with explosive action destroying entire flank communities, or if gas poor the extrusion of a slow lava dome or blocky flow ”coulee” with only local minor damage. The evolved caldera is most problematic, here the residents face similar hazards as those in Furnas. Any eruption in the caldera will be highly explosive, and even a small hydromagmatic eruption will cause damage to valuble land. A larger intra – caldera pyroclastic eruption puts the entire caldera population at lethal risk.
photo by Marco Medeiros. A Hydrangea road in the caldera of Sete Cidades
Summary
São Miguel is an excellent example showing that even sleepy volcanic islands can have a fascinating and varied volcanic geology. The fact is that most volcanic islands are like this, peaceful and green serene spaces where volcanic activity is infrequent and mostly a past memory. São Miguel is a good spot for a geology student to see almost all types of volcanology phemomena preserved as depoists in certain spots. Even a sleepy volcanic island have a lot to offer and see and because of that it has become a popular spot for geological field trip
Jesper, July 2024
Literature sources: https://www.amazon.com/Volcanic-Geology-Archipelago-Geological-Society/dp/1862397317
Sun’s up and the fog is lifting. Webcams are working. Ball’s in your court, Tutu Pele!
Really? I can’t see jack on the Hagafell camera …
Eek! I was being Hawai’i-centric!
The show is over for now: “Localized earthquake and ground deformation rates in Kīlauea’s upper East Rift Zone decreased significantly following the burst of intense activity at approximately 3:30 a.m. HST on July 23, 2024. Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW.”
https://www.usgs.gov/observatories/hvo/news/kilauea-volcano-activity-notice-kilauea-upper-east-rift-zone-unrest-has
But I expect it’s very likely that Iceland and Hawaii do something volcanic during the Olympic Games. Who will be first?
Can we award medals for the best eruptions?
Either the medal for the fastest eruption or the most beautiful Olympics Flame?
Tilt meter ESC had a second big jump down. There is (has been) ground movement in the area
Earthquakes continue to migrate east on ERZ. They have crossed through Mauna Ulu territory. Are they a tectonical consequence of the magmatic intrusion?
ESC is still moving… so the dike is still going, albeit very, very weakly.
UWE looks a bit…wonky.
?fileTS=1721776564
SDH has a little dip too although its hardwr to see. Seems there is definitely an intrusion of some size although it isnt big.
Its very interesting how the ERZ connector is where things are going yet there doesnt seem to be any easy way to either erupt or intrude. The terrain is very elevated even for a long way either side of the magma.
Might still be a few more months of magma accumulation with small events until either the ERZ unblocks and everything shifts there (not immediately I imagine) or the SWRZ connector can be pressurized back down to a lower elevation at Kamakaia area. Or maybe enough pressure exists to have another large summit eruption, which I imagine will be of a very high intensity with so much pressure now.
The situation reminds a bit to the intrusion on December 2nd 2020. Two weeks afterwrads the eruption on December 17th began.
Now we have a similar situation of overall increasing activity before the probable eruption. The location and style is a different to December 2020. But 2020 showed that an eruption can happen in short time after an intrusion.
Maybe UWE finally has found out that a dike intrusion is going on.
KOSM GPS station (SWRZ) has strongly moved west since June 3rd eruption. This shows that most magma has accumulated east from KOSM:
At the same time PG2R (southern flank of Mauna Ulu) has moved south and east. So the magma accumulation must be somewhere north and west of this station:
Big shallow quake at Torfajokull just now. Biggest I’ve seen there anyhoo.
>M3 is not unusual there. They happen about once every year or so.
Trouble is there’s no GPS or cameras there so if anything was occurring it would be difficult to spot. The quakes are around where the 877 eruption was, but as you say probably regular tectonic-induced.
Looks like Yellowstone had a pretty nasty hydrothermal explosion.
https://x.com/NomisRensiew/status/1815810415844368518
Small eruptions like this are the most realistic and dangerous risk at Yellowstone. We can forget about the VEI8 risk during our lifetimes there.
No magmatic eruptions but the hydrothermal explosions get WAY bigger than this. Mary Bay is a crater that is 2km wide and 40 meters deep, the same size as the crater left by the Castle Bravo test…
I dont think a VEI can be assigned because there isnt any magma involved but a crater that big probably has a volume around 100 million m3 which is a VEI 4. But the explosion was probably not unlike a nuke, and much more powerful than a VEI 4 eruption.
Lucky tourists. Could easily have been like the similar White Island disaster.
(Btw thanks to Jesper, I read your post last week with keen interest. The scoria cones reminded me of an old SF short story called The Railways Up On Canis by Colin Kapp. Not many science fiction stories have nice volcanoes.)
There was what appears to be a phreatic explosion in Yellowstone today
IMO are predicting an eruption in around 2-3 weeks. They say there is an equal likelihood of it occurring in the Sundhnuk crater riw and around Hagafell, seemingly preparing people for Grindavik being cut off.
https://en.vedur.is/about-imo/news/volcanic-unrest-grindavik
The Svartsengi GPS station shows that each eruption moved the station irreversibly towards the north and west until now. Deflation during the eruption doesn’t reverse this trend. Does this show the rifting of the plate boundary or the continuing magma accumulation of Svartsengi volcanic system?
From memory, the NA plate is moving WSW. The sill is close to due south of Svartsengi. I would think therefore a combination is the most likely, although the dyke would push the station broadly westward and possibly also slightly north.
Richard:
I am concerned about a south breakout of the fissure eruption and the possible damage that could be done to Grindavik.
IMO also seem to be concerned and are emphasising the blockage of escape routes within hours of an eruption around Hagafell, as well as the possibility of flowing of java through previous channels to reestablish the site that erupted inside the barrier in January. The previous article on tge 16th mentioned a general tend to the southwest also.
I volunteer for any effort to divert the flow of java … so long as it’s right into my mug. 🙂
Maybe divert arabica instead?
https://youtu.be/SBNf2W3pXY8?si=8bygwB3jCqphIpD8
Seems that intermediate mass black holes actually are a thing and there are lots of them as expected, just not randomly distributed.
Its interesting they are not crazy bright though. Of course there are quasars and AGN (maybe same thing) but there are also stellar black holes so bright you can see them intergalactic, so one would think a much more massive black hole in the dense galactic center would be very bright, not quite an AGN but probably visible.
Actually that makes me wonder, would an active Sag A* be visible? It was active a few million years ago and actually the Milky Way might be an AGN to an observer in Andromeda or Triangulum. But the galactic plain is very opaque so it might be invisible as a distinct object. Maybe Australopithecus got to see a vast diffuse luminous entity in the sky. With an IMBH close to Sag A* maybe it wont be too long to get that again. Or maybe it was a bright object that cast shadows at night and was bearly visible in the day. Maybe it is why we are so obsessed with looking up and out.
Kilauea seems to be taking a different approach to this intrusion. Its been going on for a while now, usually it is basically done in a few hours.
Still, there is no really long dike, the whole thing seems to be only maybe 2-3 km long. A 3 km long and 3 km deep at 1 meter wide would be 9 million m3 and reach the surface along all of that. The deflation at the summit would suggest 5 million m3 has left. So might be around1 km deep for the magma, but probably less unless this model is completely wrong. As long as this keeps going an eruption seems inevitable 🙂
Should be a new interferogram soon too.
MOUNTS project’s interferograms do not reach the Pauahi Crater area, though. Only hope is for HVO to release something. It’s pretty clear that a dike is very slowly growing east of Pauahi, pressure is probably low so it doesn’t unzip rapidly, while the accumulated spreading forces the intrusion to keep going.
If you look on the red earthquakes (last two hours) you clearly see an eastward movement. They have reached the Mauna Ulu area today. There still might be some intrusive activity between Aloi Crater and Mauna Ulu Crater. Aloi Crater was one which was flooded by Mauna Ulu’s eruption 1970: https://www.nps.gov/places/aloi.htm
1962 was an eruption close to Aloi Crater (two days): https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JZ069i010p02033
There are now quakes further east than Mauna Ulu too, well into the ERZ. The majority are still around Pauahi but the tilting seems to suggest the dike there isnt growing so fast despite consistent deflation of the summit unchanged from before.
But it seems like the ERZ is back now, if the above is the case then we should start seeing inflation at Pu’u O’o and maybe further east too. With the way the south caldera area has inflated recently the ERZ might inflate much faster than it did post 2018 up to 2020…
Based on tilt changes, if an eruption happens it could be very close to the ESC instrument,
Same as 1973 and 1979 then.
Well, seems like the Kilauea unrest is picking up again. There was just a 3.6 followed by a 3.0.
Looks promising.
?fileTS=1721853083
Artists thougths about the Jupiter cloud layers.. rather otherwordly and scary these endless cloudscapes must be with clouds the size of somr entire US states. These cloud towers below woud be kilometers tall. This coud be a view from the lower water condensation deck looking upwards to the ammonia- sulfides cloud deck that sits 20 kilometers above the water clouds I think. Jupiter with lots lots of windshear and very convective weather should be the ideal place for supercells ( spinning thunderstorms) Volcanoes on Jupiter are atmospheric volcanoes so perhaps Great Red Spot is a kind of Atmospheric Hotspot
Thunderstorms are enormous on Jupiter.. they are perhaps analougus to ”air volcanoes” water thunderstorms condensing on the 5 bar level can rise all way up to the tropopause 0,1 bar level so thats a cumulunimbus cloud thats around 120 kilometers high .. their cirrus anvil blowoff may form earthlike halos in the sunlight at high altitudes
Many VC readers likes this photo art so I dropps it here
Jesper, it looks like just an average 40 degree summer day in July in Oklahoma, raining at 100% humidity…
So does this mean the Dragons will allow Yellowstone talk now?
New interferogram of Kilauea up to present, showing relevant active area. Seems either there isnt a dike or this was stopped just before that happened, second option seems more likely.
HVO just confirmed that a dike intrusion is ongoing in the Upper East Rift Zone.
the area of the dike was not visible from the satellite. The uplift near Puahi is presumably part of the larger missing pattern
The focus of the ground movement seems to be east-northeast of ESC. ESC’s tilt is moving at 25 microrad per day
Interesting! The pattern of deformation is complicated and shrouded by vegetation areas were there’s no signal. The area from Pauahi Crater to Aloi Crater seems to be moving away from the satellite and is surrounded by a ring of inflation. The vegetation areas make it hard to get a full picture, but I think that the signal is produced by multiple small dikes producing an elongated graben and a ring of inflation around. Looking at the earthquakes and interferogram, it looks like the areas of Pauahi and Aloi craters have been intruded by meaningful amounts of magma, though I suspect small-scale intrusion also happened uprift. .
Also, the large Kulanaokuaiki Pali fault has gotten involved in the graben formation.
Bezymianny just had largish eruption up to 12 km, hopefully it’ll get bigger
https://www.space.com/mercury-diamond-layer-10-miles-thick-nasa-messenger?utm_content=space.com&utm_source=facebook.com&utm_campaign=socialflow&utm_medium=social&fbclid=IwZXh0bgNhZW0CMTEAAR02FnrdxpmoqaeyUjXf7Iu9OVLboxx5d7cdQjvicTzSmEaXmmQ3rzaGB-k_aem_afP2tSBXZ2ltlQeKocl2QA#lz1a340m0n9oc2rnl4t
High carbon sillicate magmas
Could this happen on Earth as well? It would explain the LLSVPs. If diamond is “snowing” up out of the outer core, and the convection in the core concentrates that into two antipodal regions, and it then mixes into the lower mantle and raises the thermal conductivity of the contaminated mantle material, that portion of the mantle will heat up as it is less insulated from the heat of the core than uncontaminated mantle nearby. You then get explanations for all of the following:
ULVZs — as heterogeneous materials (especially anything dense) dropped onto the CMB (e.g. subducted material the mantle couldn’t easily digest) get swept to the feet of the LLSVPs by convection, then pile up there, heat up, and begin melting;
Hotspot volcanism — from the melt plumes generated above said ULVZs
Rifting and flood basalts — the LLSVPs will become unstable over time and discharge “blobs” upward that detach, like the goop at the bottom of a lava lamp. A blob reaching the base of the crust will bring a lot of heat with it — and diamonds. Africa’s geology is then neatly explained by the large, tall, unstable LLSVP beneath it, from the diamonds to the rifting and the likely geologically-near-future flood basalt at Virunga. This may be how “superplume events” start. They end when the flood basalts have discharged most of the excess heat onto the surface, then the LLSVP lies dormant again for a while before it gets too big and unstable again.
Blobs of core material, like that odd iron deposit in northern Europe — an unstable LLSVP, and particularly any ULVZ material it has assimilated, may entrain core materials and transport some of them to the surface during one of these events. That odd iron deposit might have accompanied the blob that rifted open the North Atlantic and repaved much of Greenland with lava, and Iceland may be caused by the residual heat from that event, still not fully discharged.
If this is the case, LLSVPs are very important, because they are the ticking bombs that eventually cause mass extinctions. It was an LLSVP that killed nearly everything at the end of the Permian, an LLSVP that caused the Triassic extinction, an LLSVP-asteroid tag team that did for the dinosaurs, and an LLSVP that caused the PETM (but the world was still barely recovered from the Cretaceous extinction, so there wasn’t much of an extinction pulse that time). The Ordovician extinction would likely also have been caused by one, and the next one is geologically soon, to judge by how the African LLSVP has gotten tall and unstable and is already leaking diamonds and magma. Remember how highly alkalic lavas like nephelinites normally come from a very small degree of partial melting, and how they normally show up in small volumes at the starts and ends of the lives of volcanic fields. Nyiragongo produces huge amounts of nephelinites, which may be the “small volume” at the start of something truly colossal. Give it ten more million years and you might not recognize Africa any more … or the planet’s biosphere. The Cenozoic could well be over, from an LLSVP-human-industry tag team.
Activity is picking up at Kilauea again, with a magnitude 3.9 earthquake being the largest so far.
Yes, there is a new intrusion pulse ongoing, this time under Kokoolau Crater. The intrusion seems to undergo short pulses of more rapid growth separated by low activity phases. There’s been like 5 pulses already, I think. Almost as if the volcano is hesitant.
https://www.usgs.gov/volcanoes/kilauea
Or maybe building up to something, trying to break through. Saw some scattered earthquakes further down-rift before this.
Latest rates and cumulative moment
Iceland’s scientists try to compare Svartsengi with Krafla, but the script of Krafla’s 1975-1984 activity reminds rather to Kilauea’s current activity with many intrusions and the open question, when an intrusion will finally lead to an eruption. Krafla had a slow heating up before the main eruptions happened 1980-1984. Kilauea looks similarly since the SWRZ intrusion in Winter 2024.
1975-1979 Krafla did only three one-day eruptions that resemble Kilauea’s June 2024 SWRZ eruption:
– 20 December 1975 small lava flow
– 27 April 1977 fissure eruption
– 8 September 1977 fissure eruption
Krafla sequence was like what Kilauea did in 1961 to 1969, long rift with many intrusions and eruptions growing larger. Only that Kilauea formed a large open vent that created Mauna Ulu. Total volume of the Krafla Fires and Mauna Ulu sequence was similar but of course Krafla is silent now while Kilauea went on to erupt more than 10x more lava starting only a decade later… and now seems it is planning to do a round 3 as we speak. Kilauea is basically an Icelanduc volcano that never leaves its hyperactive rifting stage, or if it does then Mauna Loa takes over and does likewise 🙂
Is it possible that Kilauea is beginning to follow Krafla’s path now? It began with a major intrusion in February and a minor eruption in June. It may slowly increase in activity just like Krafla did (maybe a bit faster)
I’m sticking with the 31st July prediction I made a month ago.
Andy:
I will go with August 4th, but noticed that earthquake activity has picked up, https://en.vedur.is/earthquakes-and-volcanism/earthquakes/reykjanespeninsula/ lately.
Judging by previous episodes, I think we’re in the lead up phase. I think we’re around two weeks away.
Seems like the UWE tiltmeter has stopped going down, after 12 microradians. So about 12 million m3 of magma went into this intrusion, it will be interesting to see what HVO gives as the real number unless it isnt over yet.
I had a look at the leadup to Pu’u O’o, it seems that actually it began in a very similar way to what we see now. 1975-1977 was refilling of the ERZ after the 1975 quake, same timeline as the 2018-2020 ERZ inflation, although the 2020 eruption was at the summit not on the ERZ like 1977. 1977-1982 was mostly intrusive on both rifts, with a few eruptions, compared to today where most of this was caldera filling, and that the SWRZ actually erupted unlike in the 1980s. 1982 is very interesting.
“A major transition in the style of deformation of Kilauea volcano occurred during the period January 1982 through November 1983. Prior to 1983, the deformation was dominated by magma intrusions, rapid extension of the summit, and seaward movement of the south flank. The pattern of activity changed to magma eruption and slowed deformation of the volcanic edifice in January 1983”
https://www.researchgate.net/publication/241319048_Deformation_of_Kilauea_volcano_during_1982_and_1983_A_transition_period
In November 1982 there was strong upper ERZ quake swarm, not unlike the present one, although maybe not a dike.
The next activity was a major dike on New Years 1983 starting at Makaopuhi and involving all of the ERZ magma system up to Kalalua. It didnt stop until a little over 6 years ago…
Its obviously not a direct guide but it is entirely possible now that we are in the final runup before Pu’u O’o 2.0, maybe only months off.
I have the feeling that the slow build-up towards Pu’u O’o already began during the 1960s. There was a Napau Crater eruption 1961 with a 21 km long discountinuous fissure towards the east. Napau is part of Pu’u O’o’s larger complex. It participated in the onset of Pu’u O’o 1983 and occasionally later again with minor eruptions.
The magma which intruded now and in February, still stays and can participate in future eruptions. In June a tiny amount of the SWRZ intrusion erupted. A repeated intrusion in the upper ERZ can possibly mobilize the slightly older intruded magma. Kilauea looks capable now to do frequent intrusions in short intervals with unpredictable outcome.
M4 at Campi Flegrei, Nyamuragira is overflowing, Iwo-jima is erupting, and Yellowstone did a hydroboom. Good week for volcanoes
https://browser.dataspace.copernicus.eu/?zoom=13&lat=-1.38748&lng=29.19411&themeId=DEFAULT-THEME&visualizationUrl=U2FsdGVkX1%2F8lV41FLSBPW2katDMP88tKugJOzcy9YjsM1QPwuSpNrZKugJ3aZxAYFopvYf6iHU6ZJEUFHYVbb5A%2B9k5L7%2F0YvfGU01XtAKFT741SftZHKUm25KxwhjT&datasetId=S2_L2A_CDAS&fromTime=2024-07-25T00%3A00%3A00.000Z&toTime=2024-07-25T23%3A59%3A59.999Z&layerId=6-SWIR&demSource3D=%22MAPZEN%22&cloudCoverage=30&dateMode=SINGLE
Nyiramuragira is going full shield building now
Don’t forget about paroxysms at Bezymianny and Etna.
Lessee … two potential VEI8 progenitors, a potential VEI7/tsunami progenitor, and a potential incipient flood basalt. Good week for volcanoes; maybe not so good for humankind.
I’d prefer more little tourist eruptions in Hawaii and Iceland to increasing unrest in those other four systems, myself.
Not sure that either of the likely eruptions in Hawaii or Iceland are tourist eruptions either. Grindavik is in a game of chance, and Kilauea is likely reactivating its ERZ about a decade before it was expected to… If we get another Pu’u O’o but 10 km downrift of it then flows will be both easily be able to reach inhabited areas and also somewhat inclined to flow towards them…
To be honest I thought only last week this would be something to talk about in a few years but the 1 year leadup to Pu’u O’o was very similar to this past 10 months including very fast uplift of the south caldera, a SWRZ intrusion, a few small eruptions, and 2 months before an upper ERZ intrusion sequence… we are maybe only a few months off, things have moved fast.
Stromboli did an over average eruption today. Does the subduction zone run directly from Stromboli to Campi Flegrei (and Vesuvius/Ischia)? Is there any kind of relation/mediation between the volcanic complexes of Lipari islands and Naples’ volcanoes?
Any thoughts on the M4 quake at Vatnajökull last night? Not near any of the central volcanoes so is it likely to be purely tectonic in nature? It is a little bit east of the more active rift zones though.
There was no M4 earthquake in Iceland.
Though the USGS website doesn’t list it, it does show up on vafri.is/quake/
Look by IMO. https://en.vedur.is/earthquakes-and-volcanism/earthquakes
There has been some swarms of earthquakes in that spot west of Esjufjoll and north west of Oraefajokull. There does look like some sort of edifice there, though it’s not totally clear, entirely possible there is as Grimsvotn, Esjufjoll, Oraefajokull and Thorardynha are all equidistant.
Could equally just be tectonic and I’m talking out of my rectum.
There’s actually a hotter area above this:
https://www.windy.com/sv/-Meny/menu?temp,64.201,-17.633,8,m:fsPafHd
Okay this may be fake news. It’s cold.
Lol I thought you were trolling when I opened the link and saw a cold patch of weather! 🙂
Today was a chain of earthquakes all the way from Eldey to Hekla. Maybe a sign for tectonical rifting?
I’m more thinking about the calm at Vatnajökull last years. It was/is said that there is no negative causal relation between Vatnajökull and Reykjanes Peninsula. But all major volcanoes both at Vatnajökull and outside (Askja, Hekla, Katla) have stayed calm since Holohraun and the onset of Reykjanes Fires. Can there be a shift of volcanism to the west of Iceland during the Reykjanes Fires? If I remember the historical eruptions, during the last Reykjanes Volcanic Zone cycle, the neighbouring western systems of Snaefjalls and WVZ were also more active. How active was Vatnajökull during the Medieval Reykjanes Fires?
The List of volcanic eruptions in Iceland (Wikipedia) mentions the following Vatnajökull eruptions during 10th century (first RVZ Fires century of Medieval Age):
– 900
– 905
– 940
It doesn’t describe the quality and quantity of the eruptions, also location is unkown. It can be one of Grimsvötn’s eruptions or anything else. It is likely that the records of eruptions during these centuries are bad, there might be missing minor eruptions.
Most of the volume of lava erupted by Vatnajokull is erupted in the massive fissure eruptions. If you include Laki it makes Grimsvotn look like a heavyweight that compares to Kilauea in output but removing Laki it barely stands out worldwide. And Laki type eruptions have 5000 year recurral times in the Grimsvotn system, or only an extra 3 million m3 a year added to annual average to be able to do Laki. Reality is Grimsvotn just doesnt live up to the reputation, which should be obvious that a supposedly Kilauea competitor isnt erupting almost constantly or a 5 digit km3 shield volcano or even small LIP. Tallis may be disappointed…
Bardarbunga is more impressive but is even more controlled by rifting and seems it almost doesnt erupt at all outside of them. We just got Holubraun, I would be surprised if we see abything else from it for many decades. It might be forced into it by Veidivotn snapping in a rifting event due there in the next century. But that might well be just as much a Torfajokull or even Hekla thing depending on location. Hekla and Torfajokull are both inflating and Hekla at least has proven itself to be a powerful volcano consistently.
Only Vatnajokull volcano likely to do a powerful eruption is Oraefajokull, but probably not an actually big eruption, a VEI 4 with high intensity.like it did last time in 1727.
Volcanism in Iceland is going to be dominated by Reykjanes numerically for the rest of our lives.
Added to this the activity of Grimsvötn/Bardarbunga 1996-2014 were very much above-average activity. Many eruptions of Grimsvötn are like 1983 with local ash plume or stay below the surface only with some phreatic steam release and a jökulhlaup. 1972 f.e. was only a Jökulhlaup. 1984 only tremor without visible eruption. 1954 was only a phreatic event (VEI1). It’s possible that next eruption will be like this again.
Don’t forget we had Holuhraun just a decade ago, rather larger than the Reykjnes eruptions so far. That is probably the reason for the quiet times there since
That’s a good reason. How often does Iceland do a whole decade without eruptions of the big volcanoes? On the list of volcanic eruptions in Iceland the 1950s are an example for quiet decade. After the 1947-48 Hekla eruption Grimsvötn did a phreatic eruption 1954 (VEI1) and Katla a subglacial minor eruption with jökulhlaup 1955.
In the 20th century in Iceland,the most voluminous eruption was Surtsey at about 1 km3 or less. Next was Hekla in 1947 at 0.9 km3, so possibly the biggest. Next was either Gjalp in 1996 or Katla in 1918. Then is Hekla in 1991.
Hekla was by far the most consistently powerful volcano in Iceland in the 20th century, erupting combined about 1.5 km3 of lava and maybe another 0.5 km3 of tephra. So about the same as Holuhraun.
I think we have been very spoiled by having a VEI 4+ eruption at Grimsvotn being followed 3 years later by the 5th biggest lava flow in Icelands recorded history. Holuhraun was a VERY big lava flow, there are bigger yes and it was no Laki but to say it was an average eruption is maybe one of the things that should have been fact checked at the time…
I have got a soft bet that Kilauea will do another full volume eruption sequence including caldera collapse before another eruption as big as Holuhraun happens anywhere in Iceland.
Are you including Heimaey in with Surtsey? Some researchers do, but ~5 years falls outside of the three-month metric that HVO uses for Kilauea, for what that’s worth.
No I didnt include Eldfell as a part of Surtsey, but I dont think it would change too much, the area is not frequently active on a large scale compared to Hekla, which will usually at least over 1 km3 in a given century.
‘Cumulatively, the volcano has produced one of the largest volumes of lava of any in the world in the last millennium, around 8 km3 (1.9 cu mi).’
I do think this is being stated in a vacuum though… This isnt a Hawaii topic but really these numbers are baby steps for Kilauea. Even by equally dividing the plume with Mauna Loa and assuming only half of it gets to the surface (actually most likely an underestimate) gives 50 km3 in the last millennium, at both volcanoes. In reality its probably more like 70/30 in favor of Kilauea and more like 90% eruption rate when one of them is focussed on.
From today’s HVO report:
“Tiltmeters in Kīlauea summit region (instruments SDH, southwest of the summit, and UWE, northwest of the summit) started recording inflating this morning around 3 a.m. H.S.T, suggesting magma is no longer moving into the UERZ. Field crews returned to Chain of Crater Road yesterday afternoon observed new cracks near the intrusion, and more deformation of cracks first observed on July 23. “
Here we see a map of Italy’s subduction zone: https://www.researchgate.net/figure/Regional-tectonics-of-southern-Italy-showing-major-subduction-zones-and-faults-compiled_fig2_373429288
Etna is the excemption that it’s a volcano on a local crustal-tearing zone (maybe related to Malta escarpment). The other volcanoes both of Lipari arc and Naples look like back arc volcanoes. Can we call the volcanoes as such? Italy’s subduction zone runs through Sicily, the Ionian Sea and the eastern side of Italy’s Peninsula. The volcanoes sit on the western side of Italy.
I believe the geological term is a “Freaking Mess”. 🙂
Most of the Aeolian island volcanoes are typical subduction zone chemistry, most aren’t alkaline (except for Stromboli and Vulcano) and they have the high SiO2 for a given MgO content that is typical of arc magmas. The mainland volcanoes are highly alkaline, some even foiditic (Colli Albani), but are also strongly potassic meaning they have a very high K2O/Na2O ratio, which is typical of alkaline magmas around subduction zones (like in Tambora, or Batu Tara) and in large caldera provinces, mainland Italy is the most representative location of ultrapotassic volcanism in the world I think (with many calderas dating to the past half a million years, including Vulsini, Vicco, Sabatini, Colli Albani, Roccamonfina, Vulture, Vesuvius, Campi Flegrei and Ischia, all very explosive and very weird, even unique, chemistry-wise). Etna is a bit of a mix between a typical subduction zone volcano and an intraplate alkaline shield, in terms of chemistry and the way it behaves. And lastly Pantelleria is a typical alkaline bimodal volcano, with a sodic alkaline chemistry that’s basically the same as the calderas in the East African Rift or the Azores. It’s one of the most wonderfully complicated volcanic areas in the world.
Is the alkaline chemistry of Italy’s volcanoes linked to the dense continental environment of Europe and Afrika or is there a root in the mantle? On the Pacific ocean and ring of fire we don’t see any comparable alkali volcanism.
Hm…
From Isl. Met. office this morning; “Rivers from Mýrdalsjökull
An increase in conductivity has been observed in rivers around Mýrdalsjökull. The cause is most likely an increase in geothermal water in the affluence from the glacier. A sulfuric smell has been detected in the rivers around Mýrdalsjökull as well higher concentration of gas in the gas detectors by Laguhvolar. People are advised to stay away from rivers flowing from Myrdalsjökull glacier at this moment.”
And now there has been several surface Eq’s at katla, incl. one est. at 2,93.
10:38:18
2024-07-27
MAGNITUDE 2.93 mlw
DEPTH 0.029
(Vafri) Austmannsbunga seismometer plot looks like something is happening too.
Thoughts?
There’s most likely a jökulhlaup starting.
There were several M2 earthquakes a few hours ago. I think there may have been a phreatic event under the ice
Katla webcam has been turned to look at something.
https://www.livefromiceland.is/webcams/katla
Jökulhlaup started at 13:20.
Quoting from IMO:
“An increase in conductivity was observed in Skálm last night and increased seismic tremor was detected underneath Mýrdalsjökull glacier this morning. The Jokulhlaup started about 13:20 today and it is a large event, glacial water now flows over the ring road at 500m – 1000m across by the bridge over Skálm by Álftaver and the ring road 1 has been closed due to the event.
The Civil Protection is now in a uncertainty phase.
People are advised to stay away from rivers flowing from Myrdalsjökull glacier at this moment.”
Source: https://en.vedur.is
Katla has an aviation code of yellow.
Source: https://en.vedur.is/earthquakes-and-volcanism/volcanoes/
Tremor plot for AUS
-Mbl (icelandic news outlet) states it *might* be caused by a minor sub-glacial eruption, but I would argue it is too soon to tell.
-Ruv (icelandic news outlet) states that a bridge has been taken by the water at that the ringroad is closed. People near Sólheimajökull have been evacuated.
https://www.ruv.is/frettir/innlent/2024-07-27-thjodvegurinn-afram-lokadur-vegna-hlaups-i-myrdalsjokli-418473
If it’s the bridge I think it is, it’s always vulnerable and stretches across the whole flood plain.
It looks like a smaller bridge, perhaps more upstream
The tremor plot looks like it could be a small subglacial eruption.
I think I’ve found the bridge, it’s further east. They have evacuated Solheim, which confused me a but, presumably in case that river floods too. The Skalmar bridge makes more sense with the location of the earlier quakes.
It might be because they are worried about the impact on the glacier. Stuff could fall off it?
Struggling a bit with Google Translate.
Large amount of shallow earthquakes. Think it could be a subglacial eruption.
(Olympic?) Glacier hlaup: https://www.vedur.is/um-vi/frettir/hlaup-ur-myrdalsjokli-hlaupid-hefur-ekki-nad-hamarki
Met Office didn’t see any evidence for an eruption. It was a normal Glacier run because of thermal heat. Katla is like Yellowstone with glaciers.
I found a short article on Iceland Review from 2015. There were concerns that the Skalm was getting more water from the usual jokullhlaups, due to greater glacial melting. The local farmers were concerned about the bridge being washed away and the main ring road being closed. It was previously considered to be a small river, but floodwater us now flowing further east.
For a subglacial eruption we would need to observe tremor. If there is no tremor, a hydrothermal subglacial event (comparable to the recent Yellostone explosion) is possible. Katla has an active hydrothermal system, there might be some subglacial “Geysirs” from time to time.
Hunga Tonga caused a light cooling, not warming
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JD041296
On Iwo Jima, since 2011 it has had 2 meters of inflation even out at Suribachi and 10+ on roof of Motoyama (That 5-1 ratio seems pretty typical incidentally long-term for Iwo Jima). Assuming that inflation gradient is similar in all directions, modeling it for math as a platform+dome, Iwo Jima has had 0.45-0.5 km^3 of inflation just inside the caldera since 2011. But of course not all will be reflected on surface and clearly inflation is bigger than caldera…
Iwo-jima is such a beast that it’s not even funny. The total area of Iwo-jima is 1,260 km2, is 2 km tall, and is very flat. Total edifice volume is probably around 1,000-1,500 km3, The inflation we’re seeing is likely the result of shallow magma intrusion from a deeper reservoir. The Magma chamber is likely to have a volume multiple times larger than the edifice volume since this isn’t a shield volcano. It’s unfortunate that we won’t know the true scale of magma intrusion.
Incidentally the eruption that formed the caldera must have been a beast. The thought to be tuft layer has its bottom 500 meters below the surface. Based on the slope as you approach the rim, seems likely there would have been a nice mountain island back in the day. Depending on assumptions, 40-60km^3 DRE seems plausible (Tambora was about 40km^3). Though about 20km^3 of tuft then just fell straight back into the caldera…
On another note, interestingly the inflation bulge is clearly biased toward the southwest side of the caldera. It also helps give a hint how much inflation there has been. My guess is the Suribachi-Motoyama ~1-5 or 6 ratio for inflation goes way back. If you backtrack it, my guess is inflation started from a base 300-400 meters below sea level. Though interestingly that is probably more centered for the volcano than the caldera itself is! Iwo Jima drops off from the caldera rim rather faster to the east than west.
On a third note, assuming it is anything close to even over the caldera, 200 meters of new material post-caldera is itself fairly impressive in a 75 square kilometer caldera. Though then again pretty on track based on what we know looking at just the last 2700 years. Suribachi is not a small structure, probably >1km^3 including subsurface. I do wonder if the 700BC boom was merely an unusually big explosion during a period of post-caldera recovery. Inflation might well have started before it. Accelerated in recent centuries by the complete termination of eruptions. Maybe Iwo Jima is just a couple thousand years ahead of Yasur…
Also given just how much magma Iwo Jima seems to have been stuffing into its upper magma system I feel really the odd thing about Iwo Jima is how something didn’t decisively break (even if just as a large lava eruption) long ago.
I’m waiting for a study to get reviewed so I can write my next article concerning my big 3. But Iwo-Jima is almost definitely plugged right now and from the look of it is a big one. Most worrying thing to me right now is the fact that Iwo-jima hasn’t stopped erupting since Oct of last year. That doesn’t bode well for the plug.
Do we have any volcanocafe articles that mention snaehetta caldera? I just found out about this feature of Esjufjoll and it’s quite interesting, this is kind of uncharted territory in Vatnajokull, I think it’s probably too difficult to fully explore. Lots hidden under the ice.
I don’t think we do! Do you want to write something, perhaps?
Our best Iceland overview is in https://www.volcanocafe.org/the-woolly-mammoth-guide-to-icelandic-volcanism/
From RÚV:
Eruption getting closer (26 Jul)
Grindavik is the little town that could. I hope this coming eruption spares it again.
Bruce – “Grindavik is the little town that could.”
Reading the Iceland news, I’ve felt quite heartbroken sometimes.
The domestic householders have had the financed opportunity to move out and move on, but it seems not so for the small businesses. Looks rather harsh for those who depend on over-the-counter sales. Their customers have gone.
Lassen Volcanic National Park has been closed due to approaching wildfires, everyone is evacuated. https://x.com/LassenNPS/status/1817333808435200341
Was some quakes northeast of Mauna Ulu just today, further downrift although a bit off the trend of the ERZ connector. Seems like the recent dike might have gone about 8 km downrift. So not huge but if it had a bottom at about 2 km, volume of 12 million m3, and width of 1 meter, the dike might have been only a few hundred meters deep along that whole length. So no eruption but it might have been pretty close in a few places.
The total deflation is also only about 2 weeks of the recent uplift so if the summit starts reinflating we might get round 2 late in the month. If the summit doesnt start inflating then the ERZ might have been opened for business.
Katla has a green star this morning.
Earthquakes over 2 in the last 48 hours:
Source: https://en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/#view=map
Katla was very noisy between 5-8am GMT this morning, seems to have been a large melting event whether or not there was a subglacial eruption. Of course all this weight/pressure shift could trigger an eruption!
All quakes are too shallow (0 to 0.1 km depth) to be a magmatic source. The depth indicates phreatic or hydrothermal activity. Something between the recent Yellowstone explosion and a subglacial maar explosion.
But I think it’s possible that Katla is on a longterm trend to warming up for an eruption next 30 years. Maybe this warming up increases the risk for hydrothermal/phreatic activity below the glacier. Katla’s precursory signs include. Present geothermal activity could be a longterm indicator for a future eruption:
“Expected signals
Expected instrumental signals in the weeks to months before an eruption are inflation, onset of seismicity and increase in geothermal activity manifested in enlargening of ice cauldrons”
https://icelandicvolcanos.is/?volcano=KAT
Could the incident be caused by rifting?
The short term movement in GPS position for AUST station seems very high in the last few days. If eventually confirmed that is.
That might (speculation alert) be due to a rapidly growing lake below the ice. At Katla, it is difficult to tell eruptions apart from normal jokulhaups. Both only occur around the summer months. I think this was most likely caused by increased heat and hydrothermal activity. But with Katla (as with Grimsvotn), the johulhaup can itself trigger earthquake and even an eruption: cause and effect can be hard to separate.
Don’t forget, you have the edifice and ice-cap above sea level.
Not an expert, but I’d expect larger earthquakes to precede a subaerial eruption. I’ll dust off the tin hat if there are earthquakes over 4.5.
I’d assume that Katla gives some longterm signs before a major (Plinian) eruption like 1918. It is likely that once Katla will do its 21st century eruption. If it is 2030 or 2050, it may already begin to heat up a slowly.
One expert has said that this has all the signs of a small subglacial eruption.
Source: https://www.mbl.is/frettir/innlent/2024/07/28/ber_oll_merki_thess_ad_koma_fra_litlu_eldgosi/?origin=helstu
My feeling too. But very hard to prove, and it could ‘just’ be a phreatic explosion, involving heat but no magma.
Just Icelandic said there was change in conductivity of the water measured just prior to the heaviest outflow. Whatever it was was fairly small but melted a fair chunk of ice.
The tremor plots look very similar to the event in 2011. Here’s a paper that analyzed the tremor recordings back then: https://arxiv.org/pdf/1609.00539
Note that Páll is one of the authors.
The paper suggests either a subglacial magmatic eruption, or hydrothermal processes as the source of the tremor. Tremor from the flood water is said to have been recorded only at one station, local to the flood path, and having different spectral content then the rest of the tremor.
If the source was hydrothermal, the hypothesis is that the tremor was caused by boiling in the hydrothermal system, and possibly phreatic explosions, both induced by the pressure decrease associated with the loss of weight from the drained water. The delay between the onset of tremor and the appearance of water outside the glacier margin seems consistent with the expected time for water to flow from the source to the glacier margin. An interesting note is that analysis of the flood water from 2011 showed no evidence that it had been in direct contact with magma.
I think the hydrothermal hypothesis makes sense, but that a small eruption cannot be ruled out.
Note that Páll could potentially be biased to favor a magmatic explanation, since he’s one of the proponents of the idea that an eruption from Katla would follow after Eyjafjallajökull.
A Phreatic “Maar” eruption would work with magma-groundwater contact on subterranean level. Magma doesn’t reach the surface of solid rock to make a Phreatic explosion like this. Maybe there was a minor subglacial Phreatic explosion/eruption of the Maar type.
Apparently the 2011 event was smaller than this one.
In a small eruption, would it be possible for any ice/water that did come into contact with lava to still be under the glacier? It’s a big ice-cap.
Small swarm from 19:25 today near the site of the unconfirmed 1999 eruptive event (earthquakes and jökhlaup, again).
https://en.vedur.is/earthquakes-and-volcanism/earthquakes/myrdalsjokull/#view=map
*jökulhlaup
GeologyHub did a good video on Iwo-Jima, he estimated that the current eruptive rate is 0.27 m3/second. Lava ballons are beautiful
https://www.youtube.com/watch?v=BdP43m2dHHM
Last year’s eruption was an entire order of magnitude larger so I think last year’s eruption was worth of 10-20 million m3 of magma assuming his estimate is accurate
There have been a few quakes at 1.7 km depth. Even with the depth of overlaid ice, would this still be hydrothermal?
Quakes are concentrating around the northern end of the dike today ust south of Stora-Skogfell. Started to really pick up early this morning. I wonder if it would erupt further northeast rather than next to Hagafell as everyone expects.
Today Eldey was active at 8km depth. A slow awakening or normal seismicity?
The quakes of Sundhnukur area have stopped. Is this a sign that the eruption is getting closer? Were the previous eruptions there also preceded by relative calm?
Yes, there were periods of calm in the lead up, but in at least the last 2 or 3 there were many quiet periods with higher activity in between.
About a week ago IMO said that the refill would soon approach 16 million, but they didn’t say how soon. They are expecting another event (intrusion or eruption), at 13-19 million cubic metres. The last eruption was at the upper end. Previously it was filling at a rate of about 200,000, but the refill rate is slightly higher than before the last eruption, perhaps 250-300 thousand.
Could be but the way the rifts have behaved is that the dikes go both ways from near the middle. It is likely that fissures will open further northwards than last time and where it erupted in December but probably also equally distant to the south. The cones active in the last few months are right dead center of the rift, even if the center of the dike initiation is a bit further north than that.
I think if we get an eruption that is significantly northwards of the existing fissures, by that point Grindavik might be a place in name only…
Response to Andy
Since you are basicaly native self expert and ultimate mister know everything: my mother is going to Tasmania this winter to meet some friends and see some other stuff, she should go to the “The Nut” thats an nice old Eocene volcanic plug, the last alkaline volcanism there was mogenetic fields of very alkaline miocene era flows some being Nepehelinitic. How will the weather be like? the fact looks very subtropical maybe even warm in the lunchtime? Tasmania. sourrounded by a warm ocean and Australia being a very small continent sourely does not get the continental freezer of US and Asia on same latitudes in the northen hemisphere. So I guess there wont be any severly cold days at all so no need for real winter clothes. I have always since a small child acossiated the whole Australia with extreme heat, tought its was nearly as bas as summer in Arabia.. but thats only counts for the northen terriotries and interior continent deserts in high summer… seems like the green south is more equal to mild northen Spain than any Qatar like furnace…
You are lucky having much better weather quality than I have, yet the Tasmanian weather seems just as unpredictable and stormy as Iceland and North West Europe… perhaps UK is a good analouge even if Tasmania is closer to the equator?
It is currently 2 degrees as I type this, it is definitely not tropical 🙂 but probably not necessarily cold compared to a cold winter day in Sweden.
It is a very similar climate to England, the east coast of Australia is not the desert that the interior is and most peoples expectations are. Tasmania is very temperate and it is also very elevated, most of the state is a couple hundred meters up although all the cities are at sea level. It also rains a lot outside summer.
The Nut us also actually middle Miocene, 12 million years old. There is a cable car to the top. But if you land in Hobart it is a 5 hour minimum drive to get there if you dont stop at all so best plan at least an overnight stay. Its pretty hard to really tell that it it volcanic really, just a flat top hill. It must have been a tuff cone or maar that filled up with lava.
I have made the drive to not far away from the Nut 3 times this year, its a long drive and it isnt flat like most other long drives in Australia, 110 km/hr speed limit on 2 lane highway through hills that is not unlikely to have ice hazards at this time of year, and a lot of trucks… You want something that can fully accelerate even at the speed limit, otherwise it can get scary sometimes.
Hobart to Stanley where the Nut is, is about 400 km. Would recommend doing it in an EV
2 degrees at night and 11 at day are foercasted for the coasts… thats a near subtropical winter, thats quite warm compared to – 27 c thats typical of swedish interiors in winter I guess more air pressure woud remove the winter but the planet woud overheat in its current orbit
Subtropical doesnt get 2C winter nights. The average temperature is pretty cool but the yearly variability is much less, its basically 20 C all the time in tbe shade. Its very rare to get under 10 C at sea level in a subtropical environment. I have been to Hawaii and New Zealand, as well as a few places on mainland Australia that are subtropical and Tasmania is absolutely not anything like it. Maybe in the summer, but there is snow at 400 meters elevation right now and when I had an early morning job a few years ago at least once weekly in mid year my car window was frozen over at sea level and it has snowed at sea level twice in my life time.
Big Islands giant volcanoes makes 11 climate zones…so hard to say that Hawaii is just tropical, althrough I gives Hilo lowlands an even equatorial climate due to constant rains and high heat looked just like Singapore, Kilauea wont be a warm place for much longer in geological terms as it grows into a Mauna Loa tall beast 🙂 Kilauea at well over 1000 meters elevation can have pretty chilly january nights, I remeber reading reports of episodic snowflakes at Halemaumau sometime in the 1970 s during a cold mountain night
Not until Kamaʻehuakanaloa gets a new neighbor along the Kohala-Maunakea-Kilauea trace to pinch off Kilauea’s ERZ. Otherwise Kilauea’s ERZ will keep doing what it’s doing–growing laterally and sloughing off chunks. IMO, of course.
Yes it got to something like 1 C I think, in 1958 when Mauna Loa had its largest snowfall recorded. So about same as for me now then 🙂
I really want to camp at Kulanaokuaiki campground before it gets obliterated. Google Earth says it’s at 3100′ ( feet) but the link says 2700′. If anyone was camped there during the last eruption, they had a interesting experience! https://www.nps.gov/havo/planyourvisit/camp.htm
The deceptive point in Grindavik’s 1090 year old history was that it was excempted from lava during the Medieval Fires period, but got the direct hit during the Roman Age Fires.
The Vik (=”Bay”) of Grindavik will very probably survive the whole Svartsengi Fires. But the town will be very certainly be buried by lava and tephra. We have to expect more Surtseyan eruptions to happen towards the west offshore of Reykjanes Peninsula. Ash plumes from there can cover the whole Peninsula from Kevlavik to Grindavik and in rare cases also lightly Reykjavik.
Kilauea refilling already fast after the recent intrusion, 1 microrad a day more or less. It fell by about 11 in the intrusion so we should break even in 2 weeks or less.
Some interesting changes to GPS on 3 instruments that are pretty stable. Also seen on several other GPS sites in the area, KTPM and OKIT. Flank moving?
It looks like the intrusion moved further down the east rift, and perhaps tried to surface in this area. Didn’t work – yet
Yes these 3 got moved around a lot. The ground subsided near NUPM abd MMAU, as they both moved west, while MKAI moved south a lot. There were quakes down in this area even a little after the main event and one there just now.
There was also just a cluster of stronger mag 3 quakes on the south flank, could be related.
The deformation that showed during this event I think is too much to be just from a small intrusion of only 2 weeks supply, its very widespread. I think this might have been the ERZ as a whole unclamping, it just did it silently. I guess, before Pu’u O’o there was 1975 but the ERZ did get stuck in 1981, and it didnt have another big quake in late 1982 when it opened up. Althoughit did start flooding out lava 2 months later…
Its going to be interesting to watch the next few weeks and what moves.
https://www.youtube.com/watch?v=gJdwccH37Ss
https://www.youtube.com/watch?v=RFLUuIa8wuQ
https://www.youtube.com/watch?v=AgKfNu8Ht-s
Sooo beautyful! and correct in terms of fluid physics… when planets merges the forces are simply mega collossal! and at large scales Earth thats a mostly solid hot rock is in reality a fluid…
Congo’s twin volcanoes are active. Nyamuragira with 5km long lava flow and Nyiragongo. German volcano blog: https://www.vulkane.net/blogmobil/nyamuragira-mit-langem-lavastrom/
Thanks, Jesper, I’m amazed by this use of technology.
I liked the Theia collision, and the Andromeda/Milky Way meet-up. Which is going to happen in the future!
I suppose that somewhere in the Universe, things like this are occuring at this very moment. “Mind: blown!!”
https://m.youtube.com/watch?v=Grzfz54bVK8
More simulations … well a quick way to kill anything that lives, planetary formation is an incredibley violent process and the young Earth was extremely hot, Earth is around 100 moon masses so gives the chance for more than 70 lunar sized collisions with Earth during its infant growth
Quite accurate in fluid dynamics of large bodies but in real life it happens in slow motion, due to the immense size of these objects, it takes 10 s of minutes and hours before the mess is well mixed the energy is collossal and the animations dones not at all render the blindingly hot rock vapour that woud form a massive nebula around the reborn Earth. Its souch a slow process that you woud be able to stand for quite some minutes on the far side of Earth during souch a merger before the rock vapour envelope incenirates you
Heh. As depicted, the velocity is at least 3000 km/s, enough to completely vaporize both. Most of the debris would escape the solar system.
https://www-mbl-is.translate.goog/frettir/innlent/2024/07/26/nyjar_thrividdarmyndir_syna_rummal_hraunsins/?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp
A pretty 3d image of Svartsengi lava. More on Facebook it says but I don’t go there.
Svartsengi GPS has been lifted 40cm higher than on the eve of last eruption:
AUSV station in Grindavik is close to last deformation:
The graphs are likely too big for upload. Here the websites which contain them:
http://brunnur.vedur.is/gps/thorbjorn.html with Svartsengi station (SENG)
http://brunnur.vedur.is/gps/reykjanes.html with AUSV station
Wouldn’t that be 40mm ?
Yes. Still notable
Appears Kilauea’s south flank is doing some moving today. There’s been multiple magnitude 3+ earthquakes along it.
Interesting longterm view on UWE GPS 10 years:
The station has uplifted as much that it has recovered the 30cm lost by the 2018 collapse. UWE has recovered better than GPS stations on the eastern part of the summit.
Actually 50 cm lost and recovered. Also it is only CRIM that didnt mostly or fully recover, and that might be because it was physically lowered by being on a collapse block.
The SW part of the summit has inflated more than the eastern part. The longterm GPS graph also shows that after a period 2019-2023 with relative slow and stable development, there was a significant change in early 2023 towards more instable and fast development. Since spring 2023 Kilauea summit has been either strongly inflating or deflating, but never really stayed even. It looks as if the volcano is fighting for next eruption unlike the past when it was more easier.
Not sure why exactly but the summit magma system has changed in the last 200 years, probably in 1868. Before that there were actual vents in the central and even northern parts of the caldera, Halemaumau existed but wasnt alone. But since 1868 only the southwest end where Halemaumau is has been active, eruptions apart from 1959 have all been basically either in Halemaumau or radial to it. The area south of the caldera also uplifts and deforms like it is a part of a magma chamber despite not being inside the obvious collapse. The next full collapse of Kilauea will probably consume a large part of the area that is now the upper Kau desert area south of Keanakako’i, and it might actually not go further north than the 2018 caldera cliff. Volcano House might stay put although perhaps not be in one piece after all those quakes.
This also will have one pretty big implication. It will create a low exit southwards, so that any summit overflows will be down that way for a very long time. That area is possibly the only part of Kilauea that hasnt grown in the Holocene, being resurfaced only once around 1000 years ago. The cliff exposes both massive lava flows and even pyroclastic deposits, so evidently it was not always so quiet, nor Kilauea only producing flood lavas from its lower rifts, Pele might have big plans there again soon. Although we probably wont see it unless living to 500 is possible within a few decades…
There was a hypothesis a few years ago that put forth the Koae faults proscribed an old caldera–in that Kilauea’s summit/caldera/focus was moving *north*. I haven’t heard anything about that in a while, but there’s no evidence that it’s moved *south* either.
There has to be a point where each branch of the hotspot plume makes a jump rather than a SE-moving row of overlapping calderas.
I think the caldera location is just regional shallow tectonics nothing to do with the plate movement. The volcanoes stay active for 200 km northeast of Kilauea, and in a century time the volcanoes might only move a few meters which changes nothing.
But the idea the Koae might be related to collapses in the past sounds plausible, there does seem to be magma under the area even if eruptions cant really happen there currently. It would make sense that the volcano would over time evolve to have straight rifts. Mauna Loa is exactly that but Kilauea isnt tall enough to have control yet.
H5N1 made some progress in the wrong direction
https://x.com/rajlabn/status/1818017470592266751?s=46&t=Ox8-l5JlhQi3QBapsjTsVg
The Olympic games seem to have some problems with covid. Fairly mild at the moment but there is a fairly large outbreak in Europe, with perhaps 1 in 100 people affected. It has not gone away but is less dangerous than before, presumably because we have some immunity now.
I don’t think that Covid-19 is ever going away, I think we’ll just have to deal with it on top of the seasonal flu.
There is a theory that the other three coronaviruses occurred as a result of previous pandemics. The jury us out on whether the 1890s pandemic was as a result of influenza or coronavirus. There are papers arguing the case for both. The hypotheses work fir both largely, but there are also gaps in the hypotheses.
Probably a combination of immunity and the usual progression to lower virulence as it mutates.
The Svartsengi/Sundhnukur area lava field is doing the dust devil thing again, right now.
While we’re waiting for the next Svartsengi Fire event, Fagradalsfjall has falsified the law of “11 months dormant period”, that was accidentially working 2020-2023. One year ago the eruption 2023 was during its final days. So we have had 12 months since last eruption. Or did the missed Fagradalsfjall eruption just happen in June at Sundhnukur craters?
From the IMO:
Volcanic unrest in the Sundhnúks crater row.
Yesterday morning an increase in seismicity was measured in Sunhnúksgígaröð. The increased activity lasted for around 50 minutes and most likely it indicates that pressure is increasing in the system. The seismicity in the area has been steadily increasing in the past week.
GPS measurements show that in the last few days the uplift has slowed down slightly. This, along with the increasing seismicity, has been interpreted to indicate that an intrusion event and even an eruption could happen very soon. The likelihood of such an event occurring in the next 7-10 days has increased.
Seismic activity is picking up around Grindavik.
Agreed, I noticed it yesterday on Grindavik seismo and again today. I am guessing Friday or later. Still need a little more pressure increase I think.
Lots of seismicity west of Grindavik next to the transmitter, all at around 5-6km depth.
We have previously speculated that the magma could break out above or closer to Eldvorp.
Looks like sideways pressure from the sill, it must be close to busting by now.
This happened exactly the same before the last eruption and I thought exactly the same as you Andy. I was convinced IMO had it wrong as to where the next eruption would happen, However IMO had it absolutely correct so this time I understand their reasoning. Others were saying it was pressure causing those quakes close to the radio towers and I now think they were correct also and that it will continue to erupt at Hagafel again. How far south or north it progresses though is anyone guess.
IMO were suggesting a 50/50 chance of Sundhnukur and around or slightly south of Hagafell in an update last week. They said if it was at Hagafell, there was a high chance if lava reaching Grindavik, either by reactivating the previous eruptive site or from lava floods. The particular concern was that all escape routes would be overrun very quickly cutting the town off.
Here you can study the eruptive fissures of the Thorbjörn/Sundhnukur area: https://icelandicvolcanos.is/?volcano=REY#
They begin in the swamp west of Grindavik and are spread along a SW-NE line until Kàlffell. It’s nearly certain that eruptions will be bounded to this realm as long as the current “Svartsengi Fires” continues.
The Eldvörp eruptive fissures are a different line than the Thorbjörn/Sundhnukur craters. They won’t erupt this time, but can participate in later centuries. They look like a subsystem of Svartsengi, like Fagradalsfjall was viewed as a subsystem of Krysuvik.
The Plot (lines) are thickening …
Could be weather ..
Was a flurry of quakes at Torfajokull just now. Only a couple so nothing major but quakes in this area are basically nonexistant so it stands out.
The area faround Torfajokull and Hekla is aninteresting zone. Hekla was very active up to 2000, so presumably a high magma generation rate exists here. Both volcanoes also show inflation, and though the central volcanoes are evolved they are both bimodal and major basaltic eruptions have happened adjacent. Not sure that said eruptions really fairly constitute a separate system of Vatnafjoll, the magma isnt distinct, but egardless of our designations to the surface expressions the tectonic regime is common to them all.
Hekla-Torfajokull is also where the Reykjanes transform ends, after going through the south Iceland seismic zone. And it is also the end of the eastern and more important divergent boundary of the MAR that goes to Bardarbunga. Both Reykjanes and Bardarbunga have been active in the past decade, with major rifting and plate movement. There is also Eyjafjallajokull in 2010 showing magma generation is extensive. Hekla-Torfajokull and Veidivotn are inbetween. Its a recipe for a rift at some point I think, maybe not soon but some point in the 21st century. I think we have been paying too much attention to Grimsvotn and Katla doing normal things and ignoring the plate boundary itself.
Let’s not forget Vestmannaeyjar islands that are a kind of newer expression of the rift axis extending south of Katla. Perhaps that becomes the predominant MAR link-up via rift jump in future.
Im sceptical of that, Vestmanneyjar isnt a rifting area, nor are Eyjafjallajokull, Tindfjallajokull or Katla. And with the exception of Eldgja all ‘rifting’ eruptions of these volcanoes are radial, circumferential, or follow the topography rather than the plate boundary. Theres no submaring grabens or even transform structures to indicate anything moving out that way at all actually, so I’m not sure where the idea came from to be honest.
Theres also very little evidence of Reykjanes declining, and it technically is the only part of Iceland that actually grows directly by way of volcanism, its the youngest part of Iceland. I think it could eventually happen but it us something that might take a couple million years not a few thousand. I like Carls old articles, they probably kept this place alive and have generated endless discussions. But I feel as though they were perhaps not subject to the scientific method as much as they should have been for the more infomative and factual tone that was intended, at least in hindsight. Things like Yellowstone being a corpse, Grimsvotn being fed 0.4 km3 yearly, and the idea the huge fissure eruptions were fed by runaway decompression are all pretty questionable with newer evidence but seem to be common topics still.
“… but quakes in this area are basically nonexistant so it stands out.”
There are between 200-500 quakes at Torfajökull every year, so I don’t think you can call them nonexistant. There was some recent uplift in the caldera registered by InSAR, so it is one to keep an eye on for sure, but with that said, I don’t think today’s activity stands out.
I dont look at the area often, its usually quiet so I was under the impression quakes were pretty rare so its interesting to get at least 1 a day averaged out.
Today there are quakes along the whole Iceland rift from Eldey to Tjörnes fracture zone. Maybe there is a peak of “national rifting” which may precede next Svartsengi eruption.
It doesn’t work that way. Even during the largest dyke intrusions, the rifting has not had any effect on faults outside the Reykjanes Peninsula. Iceland has quakes along it’s active regions all the time. Sometimes several areas just happen to shift close in time, but it’s just coincidence.
How do we observe the process of rifting along the Icelandic rift zones?
It’s episodic and happens in bursts over shorter segments, maybe 20km at a time. We are in the middle of one such episode right now with the Reykjanes eruptions. Stress transfer only happens locally. Apart from the 20km segment of the rift that has been involved in the action so far at Reykjanes, only about 20km more on either side is affected, some 60km in total. Look at the triggered quake activity. It doesn’t really extend that far.
The first of the two M6.6 earthquakes in 2000 triggered quakes between M4.5-M5.5 due to stress transfer up to 90km from the epicenter. This is still a small part of Iceland in the sense of “national rifting”.
Unbelievable. They’ve shut down the mbl feed again, this time when the eruption could begin within hours. What were they thinking? How do we get their attention and then get them to walk back this decision? Hurry — time could be of the essence.
https://www.youtube.com/live/YAQzsB9ev9Q?si=gcQgTpkFHZj-eufx
This one’s live.
Thanks, but that looks like it’s pointed north of the cone. A lot of the major activity last time happened at and south of that cone. Is there reason to think it will be centered farther north this time?
Seems to’ve been re-aimed. It’s pointed in roughly the same direction as the mbl one now, but is zoomed out more.
I guess it will do in a pinch.
It is thought that the next eruption will be preceded by earthquake activity.
Unfortunately, that could give as little as 30 mins notice, depending on where the outbreak is. 30 mins could mean the eruption starts before the alert goes out.
If the lava emerges at a new site e.g. to the SW of the recent ones, there may be more seismic activity and more warning but nothing is guaranteed.
Come on, don’t be that guy! I don’t think they have actively shut down the feeds. Here are all mbl.is live feeds:
https://www.youtube.com/@mbl_is/streams
Note that all the feeds up on Thorbjörn are still active. The two that are currently down are the ones on Hagafell and Sandhóll. The ones on Thorbjörn probably have access to fixed power from the grid. The ones that are down have to rely on solar and battery. These are much more likely to fail and they are probably also much more difficult to service.
RÚV has a cam at Hagafell that’s still working:
How long does it take for a study to go through peer review?
typically 6 weeks to 6 months
Thanks, really going to be hoping for the former.
It tends to depend on the number of available reviewers in the field and/or journal. Just like all walks of life though, some are more efficient than others. It’s several years ago now, but from memory it was around 4 months for most of my papers.
My colleague, although a paper in phytopathology, had just one taking over one year. Generally, it takes 4-6 months. As an editor for a journal I can say that obtaining suitable reviewers is the most time-consuming part these days.
I just noticed that map.is has updated the satellite map layer for the area around Grindavik. It includes all of the latest erupted lava and shows the new and improved berms in great detail.
https://www.map.is/base/@332847,378938,z8,0
They have added a small berm at the base of Sýlingarfell so that lava that goes around Sýlingarfell will not immediately test the raised berm in the spot where the last overflow was. I think this is a brilliant move. They have also done a similar thing where the road crosses the berm.
The crack south of Hagafell is also clearly visible, with a dusting of tephra around it from the interaction with water during the beginning of the last episode.
Thanks for the link, Tomas! Impressive is the lava field towards Fiskidalsfjall. Without this fjell, the lava would likely already reached the coast there. Hills and mountains like Fiskidalsfjall and Husafjall were likely created by subglacial eruptions during Ice Age. They sit on a line towards Fagradalsfjall Plateau. Was there a line of subglacial fires during glaciation?
It filled up enough that it can now flow through the gap next to Husafell, which I think will probably happen next time. I will be very surprised if lava doesnt find its way into the ocean somewhere in the next eruption.
It depends on the location of the next fissure. But the likelihood for damage is rising, because the volume of first 24 hours has until now increased with each eruption. If it continues this tendency, the lava flow on 1st 24 hours of next eruption will be very voluminous and fast, where ever it goes. It may reach the ocean in the swamp west of Grindavik or over Austurvegur (=”East Way”). It may also fill up the Blue Lagoon…
The highest danger is a direct hit of the main lava flow. Before Grindavik and the germs were often spared from the main lava flows and rather had subordinated flows.
The Sat image shows that the most mass of lava went NW (Grindavikvegur) and SE (Beinavardahraun) from the fissure.
The south flow of the last eruption only went that way because it was diverted by the wall and the March lava – which was also diverted by the wall first. Without the wall Grindavik would probably be mostly gone already and heavily damaged back in January already.
If the next eruption is as big as the last one and in the same locations then it is very likely to reach the ocean at least somewhere. If a big flow goes towards Husafell and Fiskidalsfjall it will flow down the valley between them into the ocean, probably very rapidly. If lava flows south at similar rates to last time but is diverted around the north side of Grindavik it will also reach the ocean. It also could wel lreach the ocean by flowing over the south flow of last eruption and going a bit further. If the eruption isnt within August then the chances are much higher that one or more of these occurs.
It also could reach the ocean through Grindavik itself, its an unfortunate option but not exactly unlikely at some point.
I fear that the berm doesn’t resist a hard hit by a lava flow and that a possible lava flow will go to the port of Grindavik. Some lava flows of the recent eruptions were as violent as a lahar. Such a lava lahar is impossible to stop, if it arrives with full strength.
How would a ocean entry look like compared with Hawaii’s recent ocean entries? The landscape of Grindavik is more flat than Big Island, and the short life of the eruption is very different to Kilauea’s typical ocean entry eruption.
One thing we should probably be mentally prepared for given how these eruptions are front-skewed and intense, there is good odds that Grindavik ceases to exist nearly instantly whenever it happens. Either a rift extending south of the barrier or one attacking and overcoming. Grindavik at this point is rapidly becoming a pocket of low ground. With how aggressive the flow is, if it overtops in a meaningful way will rapidly erode down the barrier I suspect. It might only be an hour or two from barrier failing to ocean entry. Most of the housing is on the West side so likely out of direct impact either way, but harbor area is another story and that’s why there is any point to having a house in Grindavik anyway.
I have been watching the Sundhnukar cams from livefromiceland a little while now and there is heavy rain that seems to be coming in N -> south. If nothing else it gives a clear image of the crater rows heat signature going from north towards south. I did notice it coming in from north first, but that is probably due to the movement of the rain”storm”.
One could argue there is more surface heat now, but I can not find the link to the thermal camera right now, so not sure. I think it is very close to (hours/days) breaking surface again.
It is actually pretty much right where it zipped open last time actually. And it smoked a bit before it zipped if I remember correctly. Not to say it will now, but a little exiting.
Link: https://livefromiceland.is/webcams/fagradalsfjall
If magma were this close to the surface that it affected steaming, it would probably erupt within mere minutes, if not seconds.
Pretty sure any changes you see are weather related. Humidity, temperature, wind, rainfall, sunshine, even the current lighting situation (we’re watching through lenses) all affect how the steam looks. 😉
I absolutely agree. I have however observed increased steaming/smoking in the hours leading up to a prior eruption. But – I know…
I studied the timelapses from both cameras overseeing the area for the 30. and 31. of July and even with lots of rain and bad winds it didn’t smoke nearly as much as recently today. Again, the wind can be a factor on the last two days, so I suspect it is weatherrelated. The steam is a bit less now, but still more than in the past days. I (obvious speculation) suspect magma on the rise though. Very distinct difference in steam between north and south part of the cone. Quakes today also speak to “something” happening.
Knowing that most material erupted towards the south this is clearly not affecting what areas that steams now.
We will know for sure in a fairly short time.
Are we ready for another round of Reykjanes? 🙂
Counting down from 10 …
Kilauea is starting to have small quakes along the ERZ again already, and now a lot further east than before going down to Napau and Makaopuhi craters. Also now pretty evident that the recent intrusion wasnt just a small dike but also a major flank slip, at least major compared to anything else there since 2018. All of the stations on the south flank from Hilina Pali to near Pu’u O’o show abrupt southwards movement. Its hard to tell if thst happened east of Pu’u O’o without any GPS there but it seems likely. So far in a week is +4 microrad out of about 12 drop total, so the fact there are already quakes at this point is curious.
I really hope this dike doesn’t end up intruding into and causing another LERZ eruption but it can’t be ruled out
Deflation during the intrusion at summit stations was not as strong as the inflation before: