The Argentina volcanoes: Payún Matrú, Tromen, and Domuyo

There is a group of volcanoes that I’ve always wanted to talk about. It is a surprisingly little known, little studied location. However, about a decade ago, thanks to advances in technology, one of the volcanoes jumped from being practically uncharted to becoming moderately famous, when using satellites scientists were able to detect inflation around a very remote lake of the Chilean Andes. Laguna del Maule. But Laguna del Maule is far from the only interesting volcano here. In fact, I find some of its obscure neighbours to be even more fascinating.

Volcanic setting

Subduction zones tend to have a line of volcanoes that run parallel to the trench above the subducting plate. What is so special about the area of Laguna del Maule is that instead of a simple line, you have three different volcanic provinces with different eruption styles, and lava chemistries. There is the typical arc, with mostly intermediate andesitic magmas and stratovolcanoes. Then, behind the arc, to the east, lies another chain of volcanoes, these are dominated by felsic magmas, rhyolites, and rhyodacites. And even further into the backarc another volcanic province appears, made up of mafic magmas, mostly alkaline basalt, that form massive shield volcanoes and vast plateaus of lava.

I marked important volcanoes of the area in a topographic map from

The back-arc mafic province is known as the Payenia Volcanic Province. Its landscape is spectacular when seen from above, in Google Earth. Countless monogenetic shield volcanoes crowned with steep-sided cinder cones tower hundreds of meters above the deserted plains below. The land is covered by either basaltic lava flows, ashes from Calabozos and Laguna del Maule, or worn down granites and rhyolites from a Permian-Triassic silicic large igneous province. Grey ash, black scoria, pink granites, and a harsh, remote, human-deserted landscape stretch for 400 kilometres of the Payenia Volcanic Province.


The Payenian volcanism

The oldest Payenian volcanism forms extensive lava plateaus about 24-20 million years ago, which form a platform on which the later Payún Matrú shield volcano was built, and also extend north to Sierra de Palaoco. There are no visible central volcanoes that erupted these lavas in the Payún Matrú area, unless it was a volcano buried under Payún Matrú itself. In the Palaoco area there are three radiating dike swarms with a radius of 5-10 km, and also a separate laccolith, Bayo de la Batra, which is 3 x 2km in size and surrounded by updomed sediment layers. Each of the swarms and laccoliths may have been a small central volcano. Their age is not known, but because of their extensive erosion, that has completely removed their volcanic edifices, they might be 20 million years old or so.

Next volcano was Sierra de Huantraico, a spectacular radiating dike swarm, with a radius of 24 km, located at the southern end of the province. Dikes radiate from the ancient, deformed, and eroded summit of what must have been a huge shield volcano, probably similar to Auca Mahuida, given the great extent of its dikes. The dikes seem to follow a triple rift configuration. The age of its lavas is 18-17 Ma.

A second volcano, Cerro Bayo, formed to the NW of Huantraico, and was active a little later, around 16-15 Ma. The radiating dike swarm only reaches to 8 km. Cerro Bayo was possibly more of an explosive stratovolcano, I suspect, although it hasn’t been studied in detail. The intrusive core of this ancient volcano makes a small conical hill, whose nature makes me intrigued.

The Payenia was largely quiet between 15 Ma and 8 Ma. Although some activity did take place in the Cerro Nevado Volcanic Field, building small central volcanoes. Around 8 Ma there was a resurgence in activity. Both in the area of Sierra de Palaoco, and in the southern part of the volcanic province, in Sierra de Chachahuén.

At Chachauén volcano, the main activity lasted 7.9-5.6 Ma. This volcano has a small dike swarm, mostly less than 4 km in radius. The swarm is highly exceptional though, most of the dikes are white coloured, probably felsic composition, unlike typical dark dikes, and some are very thick. The thickest dikes are over 50 meters wide. I have spent a lot of time looking at intrusions from Southern Andes volcanoes, and these are probably the thickest dikes I’ve seen. This volcano produced large volumes of dacite volcanism, including abundant pyroclastic flows. My guess is that Chachauén was a field of fissure-fed dacitic lava domes, and was also highly explosive, producing ignimbrites fed by the lava dome collapse and/or by plinian eruptions. The composition of its dacitic and rhyolitic lavas are interesting. In a potassium versus sodium plot, the lavas match closely with that of Laguna del Maule, Puelche, and Tromen, they share the same slight sodium depletion and alkalinity. The lavas of Chachauen are different from the more alkaline (higher in both sodium and potassium) trachytes of Auca Mahuida and Payún Matrú, which are also more towards the sodic side of things, even though Chachauen is right between these two giants.

Around 2 million years ago, a major resurgence of volcanism started across the Payenia. Since then, practically every volcanic area in the Payenia has seen effusive eruptions, consisting of cinder cones and monogenetic shield volcanoes, of alkali basalt composition. The first major activity constructed the shield volcano of Auca Mahuida. The major shield erupted mostly from 1.8 Ma to 1.2 Ma, and has a total volume of roughly 900 km3. Lavas range in composition from alkali basalts to trachytes. But the evolved types seem very minor. There are only a few minuscule lava domes near the summit. A crater sits at the peak of the volcanic range, with a diameter of 1.5 km. It was probably the site of explosive eruptions with evolved compositions. Two rift zones extend to the east and west of the summit in the shape of a butterfly`s wings. Numerous cones and a few monogenetic shield volcanoes erupted great quantities of basaltic lava from its rift zones.

The E-W direction of Auca Mahuida’s rift of is the same as that of Chachauén, Payún Matrú, and Llancanelo volcanoes to the north. It is also perpendicular to the subduction. The orientation of dikes perpendicular to the volcanic arc and subduction zone reveals that the stresses during the volcanic activity have been compressive, the subduction pushes against the continent and squeezes the rock. The compression would close cracks that are parallel to the subduction and only allow for intrusions to be perpendicular to the arc. Like the rift zones of the shield volcanoes, that are perpendicularly oriented.

Volcanism during this time reached into every corner of the Payenia. It reactivated the Chachauén volcano, although with minor volumes. Cinder cones erupted from the east and west sides of this mountain. Palaoco also reactivated. Three clusters of cinder cones and shields formed next to each of the ancient radiating dike centres of Palaoco, and another cluster next to the Bayo de la Batra laccolith, all of them together amounting to 100 km3 of alkali basalts. This young Palaoco volcanism is known as the Llancanelo Volcanic Field. The last Llancanelo eruptions look very young and I guess must have happened less than 100,000 years ago. They consist of massive flows of pahoehoe lava formed in very long-lived effusive eruptions.

Around 1.3 Ma, an explosive stratovolcano grew near the centre of the Cerro Nevado Volcanic Field. This heralded the most spectacular phase of Payenia Volcanism, when monogenetic shield volcanoes started erupting all over an area 150 km across. This activity took place around 1.3-0.8 Ma judging from the few ages available. Some of these monogenetic shields have individual volumes of up to 20 km3 and are up to 700 meters high. Isolated conical mountains or chains of dark cinder cones and shields dwell in these forsaken lands. Lava flows descended their flanks and inundated the surrounding plains. They probably formed in single long-lasting eruptions, like the shields in Mexico and the Cascades.  The composition seems to have been alkali basalt. Total erupted volume is difficult to estimate, maybe 900 km3 or less.

After 0.8 Ma, activity migrated away to the distant northern reaches of the Payenia. During 0.7-0.4 Ma activity was seemingly restricted to the Northern Mendoza Volcanic Field. Small-volume volcanism took place, building mafic lava domes, scoria cones, and a few small shields. About 50 km to the NW of the Northern Mendoza Volcanic Field lies Caldera Diamante, a massive circular collapse of 16 x 20 km wide, formed during a VEI-7 eruption at 0.45 Ma. It is probably not coincidental that the Northern Mendoza Volcanic Field was active next to Caldera Diamante during its build-up to the caldera-forming eruption.


Payún Matrú

Following this 400,000 year vacation to the north, the southern portion of the Payenia reawakened, with the construction of its most impressive central volcano yet. The great shield of Payun Matrú celebrated this resurgence by making the longest known lava flow during Quaternary times, the 180-km long Pampas Onduladas flow. To reach this length, the flow benefited from a continuous gently sloping ground, a high fluidity, and a very large volume of 7 km3. The eruption was long-lived, with low but sustained eruption rates, making inflated pahoehoe lavas. It was probably erupted somewhere from the east rift zone of Payún Matrú, but the original vent is buried under the shield volcano. Pampas Onduladas is the oldest dated eruption of Payún Matrú, around 370,000 years old. Since then Payún Matrú has grown into a 1200 km3 giant, a massive pile of lava flows erupted from an E-W trending rift zone system.

Payún Matrú is a fun volcano. It erupts variable types of lava simultaneously. Mafic alkali basalts and trachybasalts from its two long rifts, and highly evolved, viscous trachyte from the summit. It has done all kinds of eruptions.

Around 270,000 years ago Payun Matru grew a satellite stratovolcano, Payun Liso. As is typical of stratovolcanoes, Payun Liso erupted intermediate composition lavas, trachyandesites and basaltic-trachyandesites. It built a beautiful symmetrical cone. Its summit crater must have produced vulcanian explosions and subplinian eruptions.

Payun Liso volcano. Image from Wikimedia, by rodoluca. Link.

168,000 years ago, the top of Payun Matrú volcano collapsed in a massive VEI-6 eruption of trachyte composition, making the Portezuelo Ignimbrite, and making an 8 km wide circular caldera.

Trachyte eruptions have continued to issue from the caldera. The eruptions happen through circumferential fissures around the west rim of the collapse. Because the fissures have opened outside the caldera, it shows that they are fed by cone sheet type intrusions, this type of intrusion, cone sheets, can be pictured as the petals of a flower, inward dipping sheets of magma that radiate from the magma chamber towards the surface. Lava issued from many vents along these fissures.

Payún Matrú. Basaltic fissures and vents in orange and red. Trachytic fissures and vents in light blue and dark blue.

I was personally surprised to see how variable the thickness of the trachyte lava is. Some of the trachyte flows are 5 meters thick or less, while other flows are over 100 meters in thickness. Sometimes the same vent erupted lavas with dramatic differences in flow thickness. Because of this, I started to doubt it was a compositional difference. After some exploring, I found that the thicker flows were associated to longer more complicated flows, usually with multiple lobes, while the thinner flows were usually found next to vents that only erupted a single sheet of lava, and usually for a short distance. Because the more complicated flows must have formed during longer eruptions with waning eruption rates, I think the thickness is controlled by the eruption rate, and distance flowed by the lava. It might be similar to the pahoehoe aa duality of basaltic lavas, pahoehoe is thinner, while aa is thicker although they have the same composition. The trachytes of Payún Matrú formed very thin flows when they were erupted rapidly during the opening of circumferential fissures, which would be a form of evolved sheet pahoehoe, but formed thick flows during slower eruptions, which would be the evolved equivalent of aa. The reason these flows grew thicker is likely because of increased crust thickness damming the flow and holding up the melt.

The trachyte fissures not only follow circumferential directions around the caldera but also a slightly radial pattern from a large crater on the west side of caldera, which might represent some kind of central vent of Payún. This crater erupted the most voluminous trachyte flow, which I estimate has a volume of 2 km3, is also the thickest flow and one of the most complex ones, with multiple lobes. The eruption that formed this flow seems to have started highly explosive, maybe subplinian, and built a large pumice cone around the vent. This flow is dated at 7000 years ago. Some other trachyte fissures seem to me that they overlie the pumice from this 7000-year-old eruption and are probably younger. Overall, it looks like trachyte eruptions at Payún are increasing in frequency, most of the flows being very young looking.

The youngest eruptions of the shield volcano are basaltic. They happened on the west rift and showered black scoria on top of the big flow and the other circumferential trachytes. The basalt events were fast and remarkably explosive. Multiple vents erupted from fissures producing tall curtains of fire and pitch-black scoria. Some of these eruptions concealed the earth in a mantle of darkness, of black basaltic pyroclasts, for up to 10 kilometres downwind from the erupting cones.  Floods of aa lava rapidly spread over the landscape around the fissures. One of the latest Holocene eruptions happened offset from the rift, to the north, at low elevations, and because of this it effused a particularly large lava flow with a volume of 0.85 km3. Although the other eruptions were also very substantial.

Holocene scoria cones of Payún Matrú, snow-covered Domuyo volcano towers in the background. Image from Pablo Flores, link.



Tromen volcano is located at the intersection between the Payenia Volcanic Province and a north-south chain of volcanoes that includes Domuyo and Laguna de Maule rhyolite systems. This chain starts at Tromen and continues north to Laguna del Maule, including numerous stratovolcanoes, mostly inactive and eroded, but the way that the edifices are partly preserved means they probably date to the last few million years or so.

They are two other similar chains that run parallel more to the north, one ends at Calabozos volcano, the other at Overo volcano. Their significance seems enigmatic to me. Some authors believe that the subduction was shallower during recent times, ~5 million years ago, and led to the formation of many volcanoes further inland, then steepened drawing closer to the ocean, to the trench. But to be true, evidence indicates the volcanic arc has actually shifted inland since 15 million years ago. The 16 Ma Melado batholith near Laguna del Maule is actually closer to the trench than any of the present-day active volcanoes. In the area of Diamante Caldera, several dated plutons show a progressive inland retreat of volcanism from 15 Ma to 5 Ma, and seemingly continuing to present, since present volcanism has receded even further than these plutons. This retreat amounts to 80 km in the area of Diamante Caldera.

Widespread uplift that has brought up these underground pluton intrusions to the surface, and has formed tall mountain ranges, intense intra-arc seismicity, and evidence of a compressive stress from perpendicular-oriented rift zones in the back-arc, are all signs to me that the subduction is gradually shallowing, and is pushing up this area of the Andes. Some of the tallest mountains in the Andes are here, including Aconcagua (6961 m) which is 170 km north of Diamante Caldera and located within the Pampean flat-slab, a volcanic graveyard of the Andes. The Pampean flat-slab seems to be eating into this region from the north at Tupungato volcano, to the south at Lonquimay. This whole 570 km section of the volcanic arc having experienced some retreat from the trench since Miocene, most intense near the northern end. The lineaments of volcanoes behind the volcanic arc must have been erupted in back-arc positions, Including Tromen.

Tromen has seen multiple stages of activity. First stage between 2.3-2 Ma involved rhyolite eruptions, lava flows, domes and widepread pyroclastic deposits. It is not impossible a caldera collapse may have taken place, although evidence is not clear. If the rhyolite magma chamber collapsed, it would explain why rhyolite volcanism suddenly vanished. Following this stage, from 2 to 1.8 Ma, there were eruptions of andesites and trachyandesites which built a complex of overlapping stratovolcanoes. At present this stratovolcano complex is deeply dissected. A prolonged dormancy came until a new episode of volcanic activity happened in 1.2-0.8 Ma. This episode involved only minor eruptions, rhyolite lava domes which were erupted from the lower flanks of Tromen over an area 20 km across. Then Tromen entered another prolonged dormancy. Some basaltic eruptions happened to the north of Tromen during this time, but these seem more closely associated to late activity of the Wayle and Los Patos stratovolcanoes to the north.

Very recently there was a reactivation, building a small stratovolcano on the north slopes of Tromen. Using topographic contours I’ve done a rough estimate of this new cone’s volume. I was interested because the cone seem to be made of multiple overlapping structures, erupted from several vents. I pictured the edifice as multiple overlapping cones and shields of lava and estimated their respective volumes. The map below shows the results of this investigation of mine. Phase of activity 1 constructed a conical stratovolcano of 10 km3. This phase was the most explosive, with likely vulcanian and subplinian activity. The lavas from this phase are relatively well preserved and I think they must be very young, maybe post-glacial, less than 16,000 years or so. If that’s true, then the whole edifice is postglacial. Afterwards eruptions happened from peripheral vents around the cone. Each eruption was long-lasting and effusive, building shield like structures, built of many overlapping tongues of relatively viscous trachyandesite lava. Some eruptions may have lasted several years or decades.

The last activity of Tromen was within historical times. Eruptions are reported in 1820, 1822, 1823, 1827, and 1828. The 1822 event, is described as a great eruption, and the 1827 event as a smaller one. No more details seem to be known. The youngest lava flows of Tromen are 5, 6 and 7, the three are extremely young looking of a similar dark-brown colour, and perfect preservation. My speculation is as follows. Flow 5, with 0.1 km3, formed in 1820. Flow 6, which has 1.1 km3, was the grand eruption of 1822-23, gas-rich ashy explosions from an upper vent of the fissure seem to have showered the flow 5 cone in fine ash, but do not cover flow 7. Flow 7, with 0.3 km3, would have been the eruption of 1827-1828, which stratigraphically overlies flow 5. The three eruptions were sustained effusive eruptions. 7 and 5 had strombolian activity at the vent. Flow 6 partitioned gas and magma, gas blew into ashy explosions from an upper vent, and lava issued from a lower vent.

Tromen volcano. Black lavas are from left to right the 6, 5, and 7 flows of Tromen, presumably formed in the 1880s. The large conical structure is the 10 km3 unit 1 stratovolcano, and on the right is the remains of the Old Tromen stratovolcano complex. Image link.



Domuyo is a huge mountain. It rises to 4,702 m. There is no other peak anywhere near as high around it, so Domuyo is the ruler here. Hence is it sometimes called the “Roof of Patagonia”. This is a volcano enveloped in mysteries and an awful lot of misconceptions. Domuyo is often described as a caldera or as a stratovolcano. There is no stratovolcano here. There is no caldera here either. But if it is not stratovolcano, and it is not a caldera, then what is it? The mountain is mostly made of Mesozoic marine sediments. But how can a volcano be made of sediments? Let’s first start with how we found out Domuyo was an active volcano.

Domuyo seen from the south, the rugged surface in the foothills of Domuyo on the left side is one the rhyolite lava flows. Image by Angel Valdez, link.

Some volcanic rocks do happen in Domuyo. A series of rhyolite pyroclastic flow deposits mantle the lower western flank on the mountain. Lava flows then erupted on top of the pyroclastic flows. The eruption history is not known in great detail, but the last eruption had been roughly dated at 110,000 years ago. As such, it was natural to assume the volcano was extinct.

The first clue that there was something special going on with Domuyo came from a 2014 article which looked at Domuyo’s hydrothermal system. The western flank of the mountain, the same area of the lava flows, has several thermal springs and small geysers. There were also hydrothermal explosions in 2002, 2007, and 2012. Three of the thermal springs continuously discharge boiling water, which is thought to have been at 220ºC before emerging to the surface, while other thermal springs discharge colder water. The article measured the thermal energy released from the springs at ~1.1 GW, which the authors believe is the second highest measured heat flux from a hydrothermal system after Yellowstone. As such, they proposed Domuyo might not be a dead volcano after all.

Second clue came from a 2019 article where, using the satellite-based InSAR technique, they found that Domuyo was inflating.  The uplift was roughly centred at the peak of the mountain and spanned an area ~20 kilometres across. The roof of the Patagonia was going up! It rose for five years, starting in 2015, and stopping by the start of 2020, reaching a total of 60 cm of uplift. Models show the source of this deformation to be somewhere 4-7 km under Domuyo, probably a sill-like magma chamber.

But there is more. As I’ve mentioned, the rocks of Domuyo are mostly sedimentary, with some interbedded igneous intrusions. The rocks are mapped as marine sediments of Jurassic and Cretaceous age. One may wonder how these marine sediments ended up at the top of the highest peak in the whole region and at the very epicentre of a magma driven inflation. I have been inspecting the mountain in Google Earth, and it is quite clear that Domuyo is a very rare structure. Sediment layers are exposed in the various glacial valleys that cut into the massif, and they always dip away from the summit of Domuyo at very steep angles. It seems as if the whole mass has been uplifted into a huge dome about 15 kilometres in diameter, which matches very well with the area that was inflating in 2015-2020. I assume that even its very name alludes to this shape. Domuyo likely comes from “domo”, which means dome in Spanish.

The coloured lines show particular contacts between sedimentary units that can followed around Domuyo. The elevation of these contacts increase towards the mountain.

One of the traceable contacts between rock layers rises up from 2200 m elevation to 3600 m as you get closer to the summit. However, the contact can’t be traced all the way to the peak due to erosion. I expect that the total amount of uplift at Domuyo is of at least 2 kilometres. Doing a simple area per height calculation, I get that a rough volume of 150 km3 of magma would have been responsible for this making this dome. This kind of deformation is seen around or above many ancient plutons, where erosion has dug down to the level of the intrusions and has exposed concentric layers of rock arranged around the fossil magma chambers, much like a cut onion, which were displaced upwards by the intruding magma. This is also seen in resurgent domes at calderas or whenever a volcano inflates. A volume of magma that intrudes into the crust must displace the rock away to open up space. This is usually upwards, although it can also be sideways in places where there is extension, such as divergent plate boundaries, or volcanoes that are falling apart sideways. As such, it is likely that a very large shallow magma chamber underlies Domuyo, probably capable of a VEI-7 eruption, which makes this system a dangerous one. Hopefully, this volcano will get abundant research in the future, although its remote location and challenging mountainous terrain doesn’t help much. However, it hasn’t erupted in 110,000 years, so it doesn’t seem like much of an immediate threat.

It is surprising though that Domuyo’s dome nature doesn’t seem to be discussed in scientific literature much. There are only a few passing mentions of this uplift. I’ve read one article that refers to Domuyo, and also nearby Cerro Palao volcano, as granitic laccoliths, while another article speaks of it as an structural dome.

Next to Domuyo lies another smaller uplift structure, called Cerro Palao. It is possibly about 11 kilometres in diameter and with an uplift of about 1 km or more. It is not as spectacular as Domuyo, but you can still see the concentric marine sedimentary layers arranged around the mountain.

Purple areas are lava domes, probably rhyolites or dacites. The two major uplifts of Domuyo and Palao occupy roughly the red circle areas.

It is unclear whether Cerro Palao is active or not. There are numerous lava domes scattered over the landscape to the north of Palao. They are bright, probably rhyolites or dacites, and heavily eroded. They seem considerably older than the last flows of Domuyo. The domes are found along a number of red scoria cones of probably basaltic or basaltic andesite composition, which time has beaten down to irregular mounds of oxide-red scoria.


Closing remarks

There are a lot of interesting volcanoes in this region. So far we’ve seen much of the province already. But a few important volcanoes are lacking. In the future I will do an article where I look at Laguna del Maule, Calabozos, and the nearby systems.



Ramos, V. A., & Folguera, A. (2011). Payenia volcanic province in the Southern Andes: An appraisal of an exceptional Quaternary tectonic setting. Journal of Volcanology and Geothermal Research201(1–4), 53–64.

Dyhr, C. T., Holm, P. M., Llambías, E. J., & Scherstén, A. (2013). Subduction controls on Miocene back-arc lavas from Sierra de Huantraico and La Matancilla and new 40Ar/39Ar dating from the Mendoza Region, Argentina. Lithos179, 67–83.

Kay, S. M., Mancilla, Ó. F. M., & Copeland, P. (2006). Evolution of the late Miocene Chachahuén volcanic complex at 37°S over a transient shallow subduction zone under the Neuquén Andes. Geological Society of America Special Papers eBooks.

Litvak, V. D., Spagnuolo, M. G., Folguera, A., Poma, S., Jones, R., & Ramos, V. A. (2015). Late Cenozoic calc-alkaline volcanism over the Payenia shallow subduction zone, South-Central Andean back-arc (34°30′–37°S), Argentina. Journal of South American Earth Sciences64, 365–380.

Dyhr, C. T., Holm, P. M., & Llambías, E. J. (2013). Geochemical constraints on the relationship between the Miocene–Pliocene volcanism and tectonics in the Palaoco and Fortunoso volcanic fields, Mendoza Region, Argentina: New insights from 40Ar/39Ar dating, Sr–Nd–Pb isotopes and trace elements. Journal of Volcanology and Geothermal Research266, 50–68.

Espanon, V. R., Chivas, A. R., Phillips, D., Matchan, E., & Dosseto, A. (2014). Geochronological, morphometric and geochemical constraints on the Pampas Onduladas long basaltic flow (Payún Matrú Volcanic Field, Mendoza, Argentina). Journal of Volcanology and Geothermal Research289, 114–129.

Germa, A., Quidelleur, X., Gillot, P., & Tchilinguirian, P. (2010). Volcanic evolution of the back-arc Pleistocene Payun Matru volcanic field (Argentina). Journal of South American Earth Sciences29(3), 717–730.

Llambías, E. J., Leanza, H. A., & Galland, O. (2011). Agrupamiento volcánico Tromen-Tilhue. Congreso Geológico Argentino18o Chapter: 51.

D’Elia, L., Paez, G. N., Hernando, I. R., Petrinovic, I. A., Villarosa, G., Bilmes, A., Bodaño, M., Guzmán, S., Borzi, G. E., Varela, S. S., Manzoni, C., Outes, A. V., Delménico, A., & Balbis, C. (2014). ERUPCIONES HISTÓRICAS DEL VOLCÁN TROMEN: ANÁLISIS GEOMORFOLÓGICO Y GEOCRONOLÓGICO EN SU SECTOR NOROESTE. Revista De La Asociación Geológica Argentina71(3), 444–448.

Lundgren, P., Girona, T., Bato, M., Realmuto, V., Samsonov, S., Cardona, C. A., Franco, L. R., Gurrola, E., & Aivazis, M. (2020). The dynamics of large silicic systems from satellite remote sensing observations: the intriguing case of Domuyo volcano, Argentina. Scientific Reports10(1).

Chiodini, G., Liccioli, C., Vaselli, O., Calabrese, S., Tassi, F., Caliro, S., Caselli, A. T., Agusto, M. R., & D’Alessandro, W. (2014). The Domuyo volcanic system: An enormous geothermal resource in Argentine Patagonia. Journal of Volcanology and Geothermal Research274, 71–77.



116 thoughts on “The Argentina volcanoes: Payún Matrú, Tromen, and Domuyo

  1. Very nice indeed Thank you!

    Im also writing on my articles as well

  2. Have always come over to this area to look at on google earth, Payun Matru is one of my favirite volcanoes to view, the contrast of the recent basalts with the brown surroundings. 🙂

    I was not aware that the eruptions there were so big in the Holocene though. GVP has some info but nothing specific, but it seems like this is a volcano that is very much alive just one that also takes its time between eruptions of large scale.
    It isxI think a very good comparison to what some if the old east Australian shields were like, like Mt Warning/Wollumbin volcano, and maybe also the much more recent Undara volcano, maybe representing what it looks like before a central volcano forms

    And aby place that has felsic magma making fluid laca flows is always interesting 🙂

    • Yes, this whole region is absolutely spectacular on Google Earth. It has some of the most impressive best-preserved silicic lava flows on Earth, piles of ignimbrites, monogenetic shield volcanoes, and a number of radiating dike swarms. The arid landscape makes it really easy to appreciate all the details. And Payun Matrú is the most spectacular to me. Such a massive volcano with an 8 km caldera. Basalt, trachyandesite, and trachyte. Shield, stratovolcano, and caldera volcanism. It has everything. It is probably similar to some of the old Australian shields. It is also similar to volcanoes like Newberry, Medicine Lake, Edziza, or Changbaishan. However, Payún surpasses all of these four in either volume, eruption rate, or both. It’s a very special volcano.

  3. Subduction has been going on for a long time here, the subduction likely becomes shallower due to plate coupling (until the slab eventually breaks off) in cycles. Payenia could be entering another ignimbrite period.

    From Atlas of the Underworld:
    The Rio Negro anomaly (Figure A72) is located in the upper mantle below western Patagonia, southern South America. It is N-S trending and partly flat-lying. It has previously been interpreted to represent still-subducting Nazca lithosphere below the Andean margin (Aragón et al., 2011). We interpret a break in magmatism in the overriding plate between ~30-15 Ma to correspond with the gap between this slab and the deeper San Matias slab. Aragón et al. (2011) estimated that subduction was re-established by ~23 Ma ago. Arc magmatism was re-established at around 15 Ma (Munizaga et al., 2002). We adopt the 23-15 Ma age range date the base of the slab.

    • The Nazca Plate is huge and will subduct for a long time to come. It is like Cocos believed to be a remnant of the Farallon Plate. Nice model of the break-up of Farallon in here:

      Really. It is called caribbean tectonics. This is about the west coast though.

      I wonder what will be then. Will South America have a spreading ridge next to it in the west like Antarctica? Or will the East Pacific Rise fail? Will there be a new plate from the plumes suspected there, like growing from Galapagos i.e.? Or three new plates?

      Will the volcanoes of South America and Antarctica be one long subareal chain, some of the peaks growing as high as Mount Everest being inactive by then? With a corresponding chain on the Pacific’s other side? With a Pacific Ocean becoming a small inland sea, North America and Russia having completely joined by then? With a new ocean, by then already considerably large in East Asia? Or two oceans, the Japan Sea and the area of Lake Baikal?
      Suspense pure, the shenanigans of the plates. Me thinks. And for this I hope for some form of eternal life to sit in heaven first row and see it happening.

      • “And for this I hope for some form of eternal life to sit in heaven first row and see it happening.”

        You and me both. I’d be floating above in my immortal bubble endlessly rewinding and fast forwarding like some firmamental Tivo.

  4. Great Piece, Héctor which I will give more time tomorrow, many details.
    Famous Aconcágua is on about the same longitude as the Payenian volcanoes, about 500 km further north as the crow flies, but stopped erupting around 10 Ma.

    I read about this that the subduction of the Nazca Plate changed direction.
    I wish you would do famous extinct Aconcágua, surrounded by shallow seas in its history, as well one day. These shallow oceans would probably have been between Aconcágua and the Payenian volcanoes.

    In order to imagine this scenario we should probably look at Indonesia. So, in 50 million years from now Indonesia might sit in South Asia and look like Chile/Argentina today.
    If man is still alive and all writing and papers preserved they will know precisely how these processes work.

    Indeed, these vocanic mountain chains in South America are impressive and hard to decipher as it is such an enormous mass. I have never been there. It must be a gorgeous continent, esp. the west, from Guatemala via Ecuador and Peru down to western Argentina and Chile.

  5. There was just a very shallow 4.2 at the summit of Kilauea. Not seeing an increase in tremor at the moment.

  6. The interesting thing is the linkage between the type of eruption and the depth of the earthquakes in that area.

    Here’s a recent one, it’s only a R4.6 but it’s at 262.5 km close to the location of this volcanic province. The white circles are 300 km. The latter are the most interesting: you can literally see where the plate is subducting, until it finally melts, along a line in mid north Argentina.

    Often those very deep earthquakes are as deep as 600 km. At the final depth the subducted plate gets to before it melts completely. There was even one of these recently that made the newspapers…I was amused since despite it being Richter 7 it was so deep (594 km) almost no one noticed it.

    It sounds like the melt from the subducted basalt from these very deep locations is making its way to the surface in provinces like this Argentinian one. Therefore producing shield volcanos.

    • Oops, something went wrong in that comment. I meant to say “the white circles are [less than] 70 km, the grey circles 70-300 km, and the black circles [greater than] 300 km”. I think WordPress interpreted the less-than and greater-thans as control codes. If you click on the key icon at the top right of the first link you’ll see the depth definitions.

      • Some of the faults in subducting plates still rupture even as it is deep below, and any coupling to the overlying plate must amplify this. It’s like the plate having a last laugh before it is sent into the depths of hell.

    • “At the final depth the subducted plate gets to before it melts completely.”

      Nope. Tomography confirms you utterly wrong in that assertion. Slab walls can be traced most of the way down to the core-mantle boundary. They most certainly do not “melt” at 600 km depth.

      Do not confuase material undergoing plastic deformation, and thus incapable of generating earthquakes, with material melting.

      • The subducted slab is cold and resistant to melting while it traverses the generic melt zone in the upper mantle. The melt instead occurs in the mantle material above the slab, which is warmer and becomes wetted by water escaping from the subducted slab. The water reduces the melt temperature of this material. But the slab does become more ductile while it descends. Some subduction zone have the slabs hanging around at 600 km, and some have the slabs steeply descending from there into the lower mantle.

      • They dont melt in a traditional sense, just becomes so hot over time that their rigid nature dissapear and merge with sourrounding mantle convection

        • Yes, basically just becomes mantle of basaltic composition I guess, only subtly differing from its surroundings. Enough to detect but not really pgysically do anything.

          I have seen a theory though, with some good evidence, that really deep powerful core plumes like Hawaii are caused by subducted slabs reacting with the outer core, which then makes a substance that is more buoyant and is very hot and rich in iron and magnesium.
          Hawaii might be a relatively unusual example of one of these core superplumes in that it is not creating a traps formation, although the volume erupted in the past few million years is very comparable to some more modest LIP provinces. A lot of things about Hawaii are rather extreme compared to many other hotspots, its temperature perhaps most conspicuously, it is the hottest lava known from at least the entire Cenozoic, and possibly even since the breakup of Pangea, if those samples from Puhahonu and Mauna Loa are being interpreted correctly.
          Perhaps if Hawaii was under a slower plate it would be a different story, maybe a great oceanic plateau, like Iceland or Kergualen, more of a basaltic microcontinent than a standard volcanic island.

          Certainly the affect of subduction is going to extend to the whole planet some way or another.

          • Quote: I have seen a theory though, with some good evidence, that really deep powerful core plumes like Hawaii are caused by subducted slabs

            As Hawai’i doesn’t have any subduction which led Wilson and Morgan a bit later to the plume theory I do not really understand where ‘subducted’ slabs would come from.

            Things like these need a reference I believe.

            Aside from that Albert discussed the LIP origin – if I remember right – here:


            Shatsky Rise and Hess Rise might be candidates. As most mantle plumes have a connection to some LIP – believed at least by some authors and OJP plus Louisville serving as an example – this is indeed a strong possibility.

          • The idea was presented on a long video by Hawaii Podd, and a few years ago now, so I dont know really how well known it is of if this was even pear reviewed, but it was an interesting idea regardless.

            But as for the slabs, they could really be very ancient, maybe even from the ocean that surrounded Rodinia, which was something like a billion years ago. At least as I understand slabs can sink very deep. This depends on how long slabs can exist in the mantle without dissolving I guess, which is not something that I am aware we know the answer to but I could well be wrong on that.

  7. I wonder whether you can express it this way:
    “the subduction pushes against the continent and squeezes the rock.”

    as basically the subducting plate disappears in the trench and parts of it in the mantle. The other parts though show up again further inland which causes stress. It is i.m.h.o. not the subduction itsself though as the plate dives under the continental plate.

    • Yes, it would be more appropriate to say that the slab is responsible for the compression. To the north of the article’s area there is flat-slab subduction, the Pampean flat-slab. The plate subducts beneath the continent but doesn’t sink into the mantle, the slab stays stuck right under the continental plate and you get strong compression, uplift, mountain building, hence Aconcagua and all the big ones there. The Pampean flat-slab seems to be extending southward, towards the Payenia. There is very intense intraplate seismicity above where the slabs hits 100-km depth which represents the leading edge of the flat-slab and belt of convergence between the two plates. This intense seismicity encompasses the area of Caldera Diamante and also reaches south to Calabozos. As the slab keeps advancing inland, it will kill all volcanoes in its wake. Maybe it will even reach the Payenia and end volcanism there. The mountains here will probably get much taller in the near-geologic-future as a result of the flat slab subduction. The image below, on the left, illustrates the ongoing seismicity and flat-slab subduction in the area.

  8. Domuyo, your last one: Fascinating.
    As you said it is “challenging terrain”, so probably not very studied.
    Could it therefore be a candidate for some mystery eruption?
    And: If it exploded in a VEI 7 what would be the consequences? 36.638°S · 70.432°W
    Ideas from anybody?

    • The area of Domuyo is completely uninhabited, so no direct proximal impact from a VEI-7. But there would be a global impact, of course. Dangers to aviation, meteo-tsunamis and a volcanic winter. Argentina, and maybe Buenos Aires itself, would get dusted in ash.

      • Domuyo is too far south to significantly affect the entire world. The entire northern hemisphere, inhabited by 90% of people, should be safe.

  9. This goes on in the south, one long line of volcanoes caused by subduction: Deception Island:

    Fortunately, a brand-new paper in Scientific Reports, led by Quebec’s Laval University, appears to have solved that enigma once and for all: it took place 3,980 years ago, give or take a century or two, meaning it shook Antarctica far closer to the present day than anyone realised.

    That matters, because this was undoubtedly the largest eruption in Antarctica in the last 12,000 years. Deception Island’s caldera-forming event ejected 30 to 60 cubic kilometres (roughly 7 to 14 cubic miles) of fresh volcanic debris, the chemical fingerprints of which made it as far as 4,600 kilometres (2,860 miles) from the vent.
    Deception Island has been erupting for the last 8,000-9,000 years, in a variety of ways. Its vents have been active in historical times, and since the 19th Century, it has erupted around 20 times, albeit fairly modestly. The last confirmed blast took place in 1970, but the last few decades of calm certainly don’t suggest that it’s extinct. In fact, it’s considered to be the largest active volcano in the Antarctic Peninsula, which means that it has the potential to impact the regional environment in the future.

    • ~2200BC ‘Major VOLCANIC eruption’. (possibly in/around Iceland, disrupting the North Atlantic and/or Arctic circulations).
      Bitterly COLD winters & indifferent, occasionally poor summers.

      ~1500 – ~1300 BC A possible ‘sharply’ cooler period (the ‘Neoglacial’), when glaciers advanced in Alaska and the Alps. Growth in peat bogs – large fluctuations (inundation) of marginal land around Alpine lakes (implies additional precipitation). [However note that overall temperatures still warmer than current – these are small-scale fluctuations – in fact we are here in a broadscale downturn in temperature from the warmth of the Bronze Age to the chillier late Iron Age.]

      So, maybe Iceland 2.200 BC, or Deception Island, or first Iceland and the DI, afterwards in the same millenium Aniakchak and Thera. Heavy.

  10. Interesting paper by scientists from Cambridge (2) and Plymouth (1) about “Global catastrophic risk from lower magnitude volcanic eruptions”; mentioning that the consequences of the Eyjafjallajökull eruption were costly:
    “This eruption remains the most costly volcanic eruption ever recorded, even when compared to the VEI 6 1991 eruption of Mount Pinatubo, which was the second-largest eruption (in terms of tephra ejected) in the last century.”

    Seven global pinch points:

    I believe that this research is focusing less on the human impact like burns or death than on huge economic losses which, of course, also has consequences for societies.

  11. Any correlation with the tectonic wriggles of the ‘Drake Passage’ ??

    • I’d say yes as it is the same mountain chain, just submarine for this passage. It is the Antarctic Plate there which meets the South-American and the Nazca Plate at the Chile Triple Junction where a slab window has been decribed.

      The distance between the Drake Passage and Deception Island is only 350 km.

      If I am wrong somebody will write his op. about it, maybe Albert.

    • The volcanoes described here are more to the north, near the latitude of Buenos Aires and Santiago de Chile.

  12. M 4.1 just south east of the town of Volcano.

    2023-04-23 00:23:47

  13. Apparently the last eruption of Payun Matru was about 515 years ago, at the Morado Sur cone, or between 1385 and 1485, nominally in 1435. This is according to Wikipedia, which gives many dates derived for flank eruptions as well as caldera eruptions, GVP only gives a date for the pumice cone in the caldera, however.

    I am not sure which cone is Morado Sur, presumably it is the one offset to the north. The frequency of eruptions in the Holocene according to the Wikipedia dates seems to be at least one or two per millennium though, so it is certainly alive although unlikely to erupt in the next few centuries.

    It does always intrigue me just how many volcanoes in the Americas seem to have coincidentally last erupted just barely before European contact. North America is abundant in volcanism but nearly all of it js from basically just Alaska, and then St Helens and Popocatepetl. Perhaps I am wrong but the past few centuries seem to have been very empty, only Paricutin and Jorullo, which were from the same field. It would ve fascinating to get another long lived shield eruption, a decades long eruption making a new mountain 🙂

    • I think Morado del Sur is the large horseshoe-shaped cone with a very long black lapilli apron. It does look like the youngest eruption of Payún. It looks like it was a relatively small eruption, with ~0.15 km3.

      There is also the Santa María flow about 1470 years before-present, which is the large 0.85 km3 flow I was talking about in the article.

      A long fissure eruption also happened in the West Rift Zone of Payún, which looks similarly well preserved as the Santa Maria and Morado del Sur flows. Looking closely at this long fissure, the flow is very complex, with a lot of different channels and changing vents which were active at different times during the eruption. This fissure eruption may have been several months long, a bit of an aa shield, probably voluminous.

      Another Holocene eruption is a flow which issues from the uppermost West Rift Zone, it showered all the youngest summit trachyte flows in black scoriaceous lapilli, including the 7000-year-old flow. Made a very long flow which curves north.

      There are one or two other fissures from the West Rift Zone that are similarly well preserved to the one from the uppermost rift.

      As for the trachyte eruptions, there is the big 2 km3 flow that is 7000 years old. There are at least 2 other fissures around the south side of the caldera that I think must be Holocene too, and maybe more than 4 in reality. Its amazing how some of the trachyte fissures of Payún Matrú resemble Galapagos circumferential eruptions. One, probably Holocene, trachyte fissure has at least 11 visible vents over a lenght of 9 km, and issued lava flows down to a few meters thick and without defined channels, a bit like sheet pahoehoe but with trachyte. The lowest vent of this fissure, instead, issued a 100 meter thick channeled flow with a volume of ~1.5 km3.

      • 9,000 years ago, potassium-argon dating.
        7,000 ± 1,000 years ago, potassium-argon dating, Escorial del Matru within the caldera.
        <7,000 years ago, potassium-argon dating, trachyandesitic lava flow in the western part of the field.
        4,760 ± 450 years before present, thermoluminescence dating.
        6,900 ± 650 years before present, thermoluminescence dating on the Guadalosos cones.
        2,000 ± 2,000 years ago, surface exposure dating, young looking lava flow in the west.
        1,470 years before present, thermoluminescence dating on Volcán Santa María although a much older age of 496,000 ± 110,000 years ago has also been given.
        515 ± 50 years before present, thermoluminescence dating on Morado Sur cone.

        This is what wikipedia says about eruptions. I think it is pretty extremely unlikely that the young black lava flows are half a million years old… That date must be from the surrounding sand is my guess.

        A lotof this seems to come from this source
        It is in Spanish, so I can read about 1/4 of it… 🙂

        Seems though that the Morado Sur cone is actually that cone row feeding the big flow field, part of which is clearly overlain by the cone that you mentioned…

        • Interesting. Morado Sur is the long fissure with the complex flow field then and must have erupted very roughly around 1400-1500 AD. The isolated horseshoe cone is Morado, and is younger given it dumped its scoria on top of the Morado Sur flows.

  14. Interesting Argentina volcanoes! Do they have extension/graben zones there behind the Andes? Etna is an example of a basaltic volcano in a larger subduction zone region, where there is a local extension zone.

    • There are articles advocating for both extension, or compression. Compression is more supported by evidence, I think, at least in the belt of Llancanelo, Payún Matrú and Auca Mahuida. Because these three volcanoes have dikes that are oriented in a perpendicular direction to the volcanic arc, which shows compression. The “push” comes from the direction of the ocean. Dikes will need space to grow, but under these circumstances, the rock can only escape sideways, so the dike will grow perpendicular to the volcanic arc and displace the rock to the sides.

      There are no grabens or normal faults in the Payenia as far as I’ve seen. But a large system of folds runs along the western side of the province and has deformed some of the old volcanoes, the Malargue Fold and Thrust belt. Tromen and Wayle have been affected by these compressional structures since their recent activity, according to some articles.

      • How can basaltic magma rise there behind the subduction zone? I’d suppose that this area is an old sea bed between the older (pre-subduction zone) South American continent and the Andes. Maybe the earth’s crust is thinner and weaker there than below the Andes and below the brazilian craton. Soft sediments are easier to crack than granite and gneiss.

        • It is not something uncommon to find basaltic volcanic fields in orogenic areas. Two other good examples are the Anahim and Stikine volcanics belts in British Columbia. Edziza volcano in the Stikine Volcanic Belt is active and is like a small version of Payún Matrú. These are two alkali basalt dominated provinces within the North American Cordillera. If you start looking around, most of the Mezozoic-present orogen areas of the world, and some of the Neoproterozoic orogens, contain abundant intra-plate basaltic volcanism. I don’t think the driving mechanisms are well understood.

          • The Stikine belt has to do with stretching. This is quite common in North America, as shown by the deep basins. Anahim seems mostly likely to be due to a weak hot spot

          • Orogenic areas usually have thick crust with a lot of plutons. Himalaya and Alpes most, but Andes also much. Is the back arc area a territory where the crust is thinner and with weaker sedimentary rock? Maybe there is some magma from the subduction zone which finds a way there from time to time.

        • With the old seabed you are right, btw. Aconcagua, 500 km further north. is believed to have been surrounded by a so called shallow sea.

  15. Good stuff Hector, this just really solidifies the fact the just because you see high levels of resurgence, that doesn’t mean high level eruptions are going to take place in the near future. I am interested in the future of this region, Ignimbrite flare up incoming in the 100,000 years?
    CCN is having it’s largest spike in LP earthquakes that we’ve seen so far in it’s 9+ years of unrest, unfortunately we don’t at what depth these quakes are taking place so it impossible to know what exactly is going on but I got some scenarios. If these are deep rooted LPs like the 2020 swarm, it would mean that more magma is ascending from the deeper reservoir and is making it’s way towards surface and will either intensify the current swarm or cause another one over the next months to a year.
    If the LPs are at shallow depths, it would either mean that magma is accumulating at depth and/or rising to the surface. Magma degassing disrupting the hydrothermal system could also be the cause. In any case interesting development.

    • Tallis,

      What’s your gut say? CCN going to erupt “soon?”

      Of course nobody can say for sure, but you’ve put as much time as anyone into researching its activity. How close is an actual eruption in your best educated guess, whether explosive or effusive?

      • My gut says it’s going to erupt explosively. We’re seeing the most intense swarm take place after 10 years of unrest. Magma is likely accumulating at depth and it could also be breaking through whatever Is inhibiting the magma ascent. The reports are unfortunately not comprehensive enough for me to make a concrete forecast. No more monthly reports from the igepn, and the sgc hasn’t made a substantial report for almost 2 months

        • In fairness to the SGC, they probably have their hands full dealing with the Lucian Alliance, now that those gangsters have been unleashed into the power vacuum created by the demise of the Ori. 🙂

          • Ironically, they released the report shortly after I made my comment…the trend is interesting.

  16. If you have clear sky tonight

    Space Weather Message Code: ALTK08
    Serial Number: 28
    Issue Time: 2023 Apr 23 2339 UTC

    ALERT: Geomagnetic K-index of 8, 9-
    Threshold Reached: 2023 Apr 23 2334 UTC
    Synoptic Period: 2100-2400 UTC

    Active Warning: Yes
    NOAA Scale: G4 – Severe

    NOAA Space Weather Scale descriptions can be found at

    Potential Impacts: Area of impact primarily poleward of 45 degrees Geomagnetic Latitude.
    Induced Currents – Possible widespread voltage control problems and some protective systems may mistakenly trip out key assets from the power grid. Induced pipeline currents intensify.
    Spacecraft – Systems may experience surface charging; increased drag on low earth orbit satellites, and tracking and orientation problems may occur.
    Navigation – Satellite navigation (GPS) degraded or inoperable for hours.
    Radio – HF (high frequency) radio propagation sporadic or blacked out.
    Aurora – Aurora may be seen as low as Alabama and northern California.

  17. Hector, this is one of your best.

    I read this at a glacial pace, absorbing every bit of info. Then I read it again.

    Wonderful piece man, keep it up.

  18. A M 2 long period earthquake has happened 40 km under the summit of Mauna Loa, followed by 2 smaller earthquakes in the same area. Deep-long-period earthquakes under Mauna Loa are very rare. They have often come in small swarms during times of high supply into Hawaiian volcanoes.

        • “Holy Four Seasons Kona, Batman!” Sits right under ‘Big Momma’. Been there!

        • I’d expect something on Hualalai this century, but could be some decades after our short human lives …
          Hualalai is in the longterm much more active than Mauna Kea. It is nearly as active as Haleakala, but with bigger eruptions (as far as I’ve read).

          • I mean, if I get to 101 I will see it, provided it goes this century 🙂

            Hualalai is a monster when it goes, it really looks like basically every eruption there is huge, or is a smal leruption in an episode of volcanism that will typically include at least one big eruption. Actually, the last eruptions, in the 1780s and in 1801, were relatively small, although the Kaupulehu (1780s) flow was erupted extremely fast compared to how most eruptions seem to be there, which is a little more modest. Although, at least from a casual observation, even slow eruptions there are pretty powerful, making tall fountains and large cones that are almost like mini stratovolcanoes, alternating lava and fountain deposits. Probably eruptions are quite long lived at times, at least months in some cases.

            One such vent, at the saddle with Mauna Loa, made a gigantic fountain, something like 1 km tall sustained, and has a volume of almost 1 km3, it made a huge wide pyroclastic cone. Some of that cone even flowed down the slope as a massive viscous flow, right next to some thin fluid lava from the same vent. This eruption was apparently in about 1000 AD, and the cone is actually nameless in Hawaiian, which is unusual.
            There was a similar eruption in 1240 AD at the Waha Pele cone, which started as a fountaining spatter cone with small to moderate flows probably a lot like the Fagradalsfjall eruption in 2021. That was until it suddenly blew itself up to make the only maar in Hawaii, and within that maar the vent evolved into a raging flood lava volcano that then promptly went on to flood 40 km2 of the island downslope, it was an exception to the trend of decreasing intensity as the eruption goes on, which might be a thing to note for a future eruption.

          • After the eruption 1801 Hawaii had a strong intrusion at Hualalai in 1929 with a powerful earthquake swarm: 6,200 earthquakes of which two had magnitude 6.5. Even if we don’t get an eruption at Hualalai, an intrusion like 1929 would on it own make much noise and cause damage to houses.

            Hualalai also makes more explosive eruptions, a bit like La Palma 2022. It has alkali basalt and more water interaction (phreatomagmatic eruptions).

            Unlike Mauna Kea Hualalai still has active rift zones: A NWRZ and a SERZ. 1800-1801 was on the NWRZ, in the Middle Ages (around 1240) an eruption was on the SERZ. Often those eruptions were swarm eruptions with several events over a short time.

          • Alkaline basalt of Hualalai is only alkaline compared to Kilauea and Mau a Loa, it is not very alkaline by world standards, as I understand.

            But yes it does have more powerful eruptions, the magma storage is deep, so all eruptions come from massive dikes racing up, it is actually a lot like how Hekla probably behaves. No shallow system means it is very seismic, although I imagine the 1929 swarm was because it didnt erupt, the presence of so nany xenoliths in the lava probably means it erupts very fast, maybe only days after the intrusion begins. So the lava will be very gas rich, compared to most eruptions at Kilauea and Mauna Loa.

            That being said, a mag 7 quake followed by a flood of lava directly uphill is basically the quintessential volcanic disaster…

          • Indeed, the magma of Hualalai is only “little” alkali, but compared with Tholeiitic magma different. But the main “postshield stage” of Hawaii (Hualalai and Haleakala) is the maximum some medium strong Hotspots can reach. The real shield stage with effusive Tholeiitic basalt is only in the big hot spots like Hawaii, Reunion, Iceland and Galapagos.

            Hualalai is Hawaii’s possibly most expensive volcano. There is a lot of tourist infrastructure like Hotels and airport which can be destroyed by lava, earthquakes, explosive events. Mauna Loa can also send lava to this area by radial eruptions (1859) or can do Surtseyan eruptions offshore to the southwest of Hualalai (1877). But those eruptions are supposedly a smaller threat than a Hualalai eruption.

          • Kona area is complicated, because it is at risk from both Hualalai and Mauna Loa. In theory Mauna Loa is more dangerous, but then in reality the actual number of flows from it that have gone near inhabited areas in north Kona is basically just 1 in 1859, major radial eruptions like that seem to be very rare, maybe a couple times a millennium. ‘Minor’ radial eruptions that are basically shallow drainage from a vent elsewhere seem more common but are usually on the smaller side, although 1877 was of this type and one of the largest historical eruptions, it is all complicated when the vents are down low…

            Hualalai though, it is hard to see it not being a major event, no matter what it does, and though it is not frequently active it has covered more of this part of the island than Mauna Loa has since settlement, at least at the coast where people live Kilauea and Mauna Loa are mostly harmless in their common eruptions, only eruptions at low elevation or rare explosive activity at Kilauea is a real hazard to human life. Hualalai though I can see being much more dangerous, and probably will have a body count. Its like Nyiragongo but its eruptions are like 50x bigger and it throws a mag 7 quake as a warning before it opens the gates of hell… maybe it can be argued a pyroclastic flow is more dangerous but you arent outrunning fluid lava on those slopes anyway and most stratovolcanoes arent known for pre-eruption seismicity of any serious magnitude…

            Its also that the Koba area in general might only get lava once in a century on average and maybe even less, so the lava is much more scary, the small flows southwest of the summit last year caused evacuations, a proper SWRZ eruption would be much worse.

    • Seems like this is the most Mauna Loa important swarm since that of 2016. So far, three catalogued 40 km deep LP earthquakes in 2 days. The 2016 swarm produced 8 catalogued earthquakes in 3 days. The 2016 swarm did not precede any obvious increase in supply, though. A swarm of 11 earthquakes in mid-2014 did precede a major pulse of inflation at both Mauna Loa and Kilauea, as did larger DLP swarms in 2002 and 2004-2007. Some swarms in the 1970s and 1980s were also linked to pulses in the activity of Hawaii.

      So far, it is very small and probably nothing important. But if it continues or escalates in strength it could get interesting.

      • There were also two very LP-looking M 1.9-2.4 earthquakes from several hours ago hours ago, 6-8 km under the summit of Mauna Loa. I didn’t know Mauna Loa could do long period earthquakes at that depth.

        • Seems HVO afjusted the deep quakes now they are all showing as being small, still interesting activity and probably means it wont be another few decades before the next eruption.

          Surprised you havent commented on that 4.1 just east of Kilauea Iki though, very unusual quake and quite big too for being so shallow.

          • Seem like a fault slipped near Kilauea Iki. I have no idea what a fault is doing there though, very odd location. But I don’t fully understand the Namakanipaio swarms either. Kilauea somehow creates strain that makes earthquakes west (Namakanipaio and east (Kilauea Iki-Volcano). I get the feeling that the eastern area has intensified recently, and there weren’t many earthquakes there before, so maybe it has something to do with the growth of the magma chamber, but I will need to look more into this.

          • I have done a quick search in IRIS. This is how Kilauea seismicity was distributed in 1982 during a time of intense presurization, earthquakes only in the connectors and nowhere else:

            This is how it looks now, with swarms east and west of the summit, and also within the caldera:

            The Namakanipaio swarms west of the summit first appeared with the aftershock sequence of the M 6.6 earthquake of Mauna Loa in 1983, and since then there have been earthquakes in that location every year. Seems to have to do with sliding of the flank.

            The caldera earthquakes and Kilauea Iki swarm appeared mostly after the 2018 collapse. Partly due to the formation of new faults, I expect.

            The M 4.1 a few days ago produced the first swarm of earthquakes that has been registered in the Volcano Village area in the past few decades. It will be interesting to see if this was just an isolated event or if earthquakes will keep happening there.

          • It is pretty clear how much more widespread the quakes are now, there was basically nothing actually in the caldera before but very much not the case anymore. The SWRZ conduit is still there, maybe even a bit longer than in 1982, although not as many quakes. But the ERZ is completely quiet, there might be a bit down at keanakako’i but it all stops at the outer caldera fault, so really the rift is basically dead at the moment. And then there is Kilauea Iki…

            It would be great if there was a detailed record of the seismicity of the 1950s. 1955 was much smaller than 2018 but in the same area, a LERZ eruption, and it was obviously followed by the eruption in Kilauea Iki in 1959, and then in short order by a much more powerful LERZ eruption. There are differences, the caldera floor was solid and much higher then, so the whole eruptive episode basically started at a high point and perhaps this is why the ERZ was so active. But then, nowdays the caldera floor is not all that much lower already, 900 meters elevation vs 1050, so things could well be more comparable than it seems. The 1959 eruption was unusually seismic compared to typical summit eruptions, and the intensity was sustained for the whole thing, not just the first couple hours. The lava was also variable chemistry but included some really primitive stuff, at least all of this to me says that the lava was not erupting as a satellite of Halemaumau but was its own thing, possibly with some fairly deep roots. There being quakes in the same area might be something of an early sign of future activity at Kilauea Iki.

          • Kilauea Iki 1959 began as a unique eruption with an own rise of magma from deeper reservoirs. I don’t think that something like this is likely. We would need to have more deep swarm quakes there.

            The present quakes show that we should expect something in the summit region and upper rift zones. There is a big variety of possible eruptions. Maybe we get several short, but exciting ones with more dynamic behaviour unlike the longterm and more steadily active lava lakes.
            During Mauna Ulu’s eruptive period there were at the same time several smaller eruptions in the summit region. F.e. 1971 Kualapele (summit caldera and SWRZ, 1973 Hi’iaka Crater and Pauhai Crater (UERZ), 1974 fissure eruptions in Kualapele and the upper SWRZ. Over a short time there can be a big variety and change of eruptions.

          • There actually have been swarms deeper under Kilauea, about a month and a half ago there was a set if at least 6 mag 3 deep blue quakes at the same depth as the Pahala quakes, all more or less right aroubd Kilaueas summit. And then only last week there was actually a clearly visible stack of yellow depth quakes going down about 13 km directly under the summit, and then not long after was the surge in shallow quakes we see. At the time of the 1959 eruption supply was relatively low, actually this eruption was probably when Kilauea actually got its high supply of recent years, not least because it then all drained out east and that only created a feedback loop.

            So a new pulse if magma from deep down like 1959 might not be easily visible now. That is why these quakes at Kilauea Iki are so interesting 🙂

          • The lavas of the 1959 and 1960 eruptions are the most alkaline Kilauea has erupted, and are also among the most magnesium rich. I think it is related to how Kilauea had low activity from 1850 to 1960. The alkalinity of Kilauea’s magmas had been increasing and peaked in 1960. Since 1960, the magmas have become increasingly tholeiitic, and have also leaned towards having less and less magnesium. Additionally, 1959 and 1960, were large eruptions that after draining some of the lighter magma probably started tapping into magnesium-rich melts in the deep rift. Both eruptions were exceptionally gas rich and produced huge fountains even though they were “normal” fissures, not caldera-forming events like Hapaimamu, Panaewa, or Puu Kaliu, and not satellite shields either, like Mauna Ulu or Pu’u’o’o.

        • There were M2.6, M2.9 and M3 this morning, all slightly above sea level, south of ML’s NERZ. I’m going to guess a dike contraction, or maybe compensation for the activity around Volcano Village and Iki.

    • Over the past 2 days, Mauna Loa inflation has practically stopped, after some days of more vigorous rise, and now we have a surge of inflation of Kilauea in the past day or so. We will see how the graphs look in a few days’ time, but I’d say there’s a correlation. It would be the third time this happens since the Mauna Loa eruption.

      Also, the deep long period earthquake swarm of Mauna Loa might be ramping up. Over the last three hours, there have been rhythmic signals in Mauna Loa seismometers that look like repetitive LP earthquakes. The past week graph of Mauna Loa shows 16 earthquakes deeper than 30 km, although only 4 have been catalogued and manually located. This is exciting. I’ve always wanted to see one of these swarms unfold. The 2004-2007 DLP swarm of Mauna Loa preceded a very important period of activity that involved increased CO2 emission rates of Kilauea by a factor of 2.5, sped substantially deep rift spreading of both volcanoes and shallow inflation rates, possibly doubled Pu’u’o’o effusion rates. It might also have been involved in the eventual birth of the lava lake in 2008, and the start of frequent DI events. So far, it’s an insignificant swarm compared to the one that started in 2004, but who knows.

      • Looks pretty much like the eruption earlier in the year was just a temporary diversion to the long term trend, the deflation was much less than the eruptions in 2020 and 2021.

        Also the ERZ is still showing the downward trend, but there is an interesting pattern. Back when Mauna Loa was active the contraction also stopped, as it did recently. Not sure what this could be exactly but it is interesting.

        • Also pretty incredible that even with eruption ongoing for half of the time the cross caldera distance has increased by almost 50 cm, and 10 to 15 cm up since I was there today last year 🙂

  19. This paper cpould be interesting, Héctor and others:

    The occurrence of a Neogene shallow subduction stage, as well as, a Pliocene slab-tearing, and steepening of the Nazca plate in the southern Central Andes are well established. However, a satisfactory explanation for the origin and connection between these complex processes is still elusive. In this contribution, we revise the late Cenozoic tectonic and magmatic evolution of the southern Central Andes between 35° and 38° S and discuss different proposals for the Miocene slab shallowing and its Pliocene destabilization. Recent plate kinematic reconstructions show that Neogene arc-front expansion linked to slab shallowing, fold belt reactivation in the main cordillera and intraplate contraction in the San Rafael Block correlates with the subduction of the ancient Payenia plume, a deep mantle anomaly potentially rooted in the lower mantle. Also, the Nazca slab tear determined from tomographic analyses and subsequent slab steepening may also be a direct consequence of this plume subduction process. Considering the westward drift of South America and the presence of several neighbor hotspots over the Nazca plate, the Payenia plume overriding could be the first of future episodes of plume–trench interaction in the Andes.

    • Thanks Denaliwatch. I think I have read these authors before. There exist many inactive stratovolcanoes in the present-day back-arc, most of them probably less than 2 million years old, which suggests maybe there was flat-slab subduction over the area until very recently, reaching at least as far south as Puyehue. But 6 million years ago subduction was steeper than it is at present, given that a very well dated pluton formed at this time west of Laguna del Maule, and two other plutons west of Calabozos and Caldera Diamante are dated at 5-7 Ma. So the timing of flat-slab subduction given in those articles is not consistent with data, I think. ~6 Ma was a time of steep subduction.

  20. I just had a random thought regarding the P/T extinction, not sure if anyone in here has an informed opinion or thought on it.

    We know from various sources that the P/T extinction was essentially a gigantic episode of climate change spurred by the eruption of the Siberian traps (and subsequent cascading changes throughout the global climate). One item that has been fairly well studied is that part of the reason this was so extreme was that the Siberian traps erupted through a carbon layer, basically causing massive fossil fuel burning, forcing the enormous co2 spike that raised average water temperatures to as high as 100 degrees.

    With that out of the way, do we have any evidence whether this caused mass forest fires as well? That would make sense as a natural tipping point given the heat increases as well as the fact that you would get more aridity in a lot of regions. This likely would have also been yet another item that contributed to the mass extinctions.

    • I’ve read lots about The Great Dying as it’s such a remarkably extreme event that we’re very fortunate the earth was able to re-calibrate from, with life intact.

      I can’t answer your question directly and am sure others more informed can probably offer more, but it does seem logical that as global temperatures began warming as the eruption persisted, that incidence of large wildfires would increase and could act sort of as a secondary warmth forcing.

      I see a tipping point more as a system that switches between states like the AMOC, or as a trigger for a relatively short term highly impactful event (methane clathrates, etc). I would think fires caused by the traps would be more of a randomized but still high impact event, unless an enormous % of forested areas ultimately burned.

      • That describes conditions going into the late Permian, stressing most life, but the actual extinction event was caused by a second shoe dropping: basically, Earth had a heart attack.

        The paleoclimate has all kinds of variations, but in the end you can group these into two major overall states, with various sub-states.

        One of these is the zonal flow state. This happens when landmasses are patchily distributed and there are east-west ocean circumnavigation routes that stay in the low and mid latitudes. Under these conditions, the ocean currents mainly flow east-west and do not mix heat, or oxygen, into the deeper waters. The oceans become stratified, with a stagnant lower layer and a circulating upper layer. The lower layer may go through anoxic episodes, as occurred during the Jurassic. The upper stays well-mixed and well-oxygenated, but tends to be nutrient-poor. Sea life is dependent for nutrients on outwash from rivers from land. The overall climate is a hothouse, but a fairly even one from pole to pole and (from the Carboniferous onward) typically most of the land is lushly forested; there is a vigorous hydrologic cycle. The last time Earth was in this state was in the Eocene.

        Zonal Earth is well oxygenated at the surface by land plants and by algae feeding off river effluents. The deep oceans tend to be hypoxic and undergo episodes of outright anoxia. Before the Carboniferous, there was little plant cover on land and little land-based oxygen production. Earth was much more oxygen-poor: the oxygen partial pressure at sea level 400 million years ago was like that in Denver now, if not higher. If you took your time machine back there without acclimatizing first you could get altitude sickness.

        The other major ocean current state is meridional, occurring when land forms one or more continuous north-south masses from pole to pole, or nearly so. The closing of the Tethys caused the Earth to enter the meridional state geologically-recently, and it is in that state now due to the Eurasia/Africa land-mass. It was also in that state in the late Paleozoic, through into the Triassic, due to Pangaea. During meridional circulation, ocean currents run mainly north-south, and they also run up and down. At high latitudes cooling water sinks, bringing oxygen to the deep ocean, and where it rises again it dredges up nutrients from the deep, which fuels massive algae blooms that can produce oxygen. Much oxygen comes from this source during these times, with less coming from land. The climate is far more variable, susceptible to ice ages as well as hot periods, and it is overall a drier climate. Land is less forested (especially during ice ages) and produces less oxygen.

        Sufficient warming during meridional periods can be extremely dangerous. Heat and/or freshwater from melting ice can prevent water from sinking near the poles, and the entire ocean current system can seize up. Land blocks a zonal current regime from taking over from it. So, the oceans as a whole stagnate. With the formerly main mechanism for transferring heat poleward shut down, the atmosphere must take up the slack, which means strong upper-level winds. That, in turn, means shear that kills off hurricanes. Land, already undergoing widespread drought, loses another source of rain, while one mechanism for stirring oxygen into surface waters is lost. The current shutdown also stops the nutrient upwellings that fueled algae growth, the major oxygen producer at sea, and the major oxygen producer on land, forests, has long since been decimated by drought. The planet has, for all intents and purposes, had a heart attack. Nutrients and oxygen are no longer flowing because the pump has shut down.

        When this happens, almost everything dies, and the planet only recovers when enough greenhouse gas is scrubbed from the air by various processes. The lack of plant growth to draw down CO2 means this is largely dependent on weathering of rocks and similar abiotic processes. It takes a while. A major orogeny can speed it up, as (ironically) can volcanism, by exposing fresh rocks for weathering.

        The PETM didn’t cause a major extinction because it hit during a period of zonal flow, when Earth is more resilient to such shocks. Note the lack of major mass extinctions from the Jurassic through the Eocene. On the other hand, there was meridonal flow during the Permian and Triassic, and flood basalts at the end of each of these did cause mass extinctions. There was a smaller extinction at the end of the Eocene, when the zonal flow was becoming weak and the hothouse was ending.

        Our current warming spike, dangerously, also comes at a time of meridional circulation. And that circulation is vulnerable. Some think there was a brief shutdown at the start of the Holocene, caused by freshwater flooding the northern sea, but as we were just coming out of a glacial at that time the land was in a comparatively wet and lush state (away from the high latitudes that is), maintaining one source of oxygen, and the shutdown was brief as the melting glacier causing it was soon gone. A shutdown happening now, with a much warmer and drier climate than then (there was grassland where the Sahara is now), would be vastly more dangerous, especially if it was prolonged. Melting ice would likely be the initial trigger, but if the air and surface water in the polar regions got warm enough, it might not be able to restart until a lot of CO2 got scrubbed.

        The Younger Dryas was a planetary angina episode, a warning. If we do not heed that warning and make some lifestyle changes, next time it might be the real deal, and we could end up going the way of the trilobites.

        • This was a super thorough and interesting response. Thanks!

        • This might all be right, albeit complicated. It needs to be noted though that the reason might be mainly mechanical. The creatures at the end of the Perm were marine creatures, huge ammonites i.e. As the shelves were rarified at the time of the closure of Pangaea and the sea levels very low, contrary to today!, many of the marine creatures lay bare and dried out, helped by the volcanism of the traps which was huge.

          The beginning of the Triassic (with Pangaea still intact) showed an astonishing proliferation of life in the form of early dinosaurs. So, a very different life began, land life on Pangaea, whereas before, in the Perm, there was mainly marine life.

          So basically, the term extinction might be wrong, also at the KPg-boundary as change might be the better term, change of the form of life. When the giant ammonites said good-bye, the dinosaurs evolved, proliferated into land-, then sea-, and air-species and staid for around 180 million years, a long time. And when the dinosaurs died out, there was a proliferation of the mammal. Life changes all the time and has bell curves of different size.

          The only extinction that I couldn’t call change or adaptation is the killing-off of creatures by man. Maybe the one and only extinction.
          The difference between the PT event and the KPg event is that marine life was hugely shut down and land life began, whereas 65 to 66 Ma the small mammal and the reptile existed together and the small mammal survived in the same surroundings. This seems very different to me.

          PT: The end of the ammonites had come, and that was marine life and only marine life.
          KPg: The end of the dinosaur had come on land, in the oceans and also in the air, but not completely, the shark in the ocean and the mammal survived.

          There might be just an end to like there will be an end to the Solar System and later on to the Cosmos. There might be considerable predetermination.

          • The Permian had abundant terrestrial life, as much as the Triassic. It is older and the average size of animals was somewhat lower than later periods, so fossils are not as diverse, also that a great deal of the sites (including Perm itself) are in Russia which makes access difficult and can present a language barrier.

            The Devonian was when life on land started to proliferate, although mostly plants and arthropods, the Carboniferous saw tetrapods take to land properly, and ever since they have been abundant. The Permian lasted for almost as long as the Cenozoic has gone on for, 50 million years, abd each half was at least 20 million years, life right before the P/T would have been at least as evolved as the stuff around towards the later part of the Triassic.

            Also there was much more than only ammonites, chondrychthian fish were very successful, as diverse in ecology as the marine tetrapods of later times. Things like Helicoprion and Edestus. It was not a primitive world of things waiting to become dinosaurs later 🙂

          • That’s certainly true, Chad, but marine life was probably more significant.
            And it needs to be mentioned that the first proliferation of the Triassic was not Dinosaurs, but Archsaurs.

            Which is not the interesting point. The only interesting point here is whether in the Cosmos underlies laws od predetermination.

          • Dinosaurs are one group of archosaurs, like how mammals are one group of synapsids. So the rise of archosaurs was directly linked with the dinosaurs dominance later on, although it is unlikely dinosaurs would have been nearly so dominant without the later T/J extinction too.

            Marine life has always been overall more total biomass than land life, there is about twice as much ocean after all. I have not seen any study or other data that suggests the oceans of the Permian were significantly different in terms of food webs and cycles, only that there were no marine tetrapods at least none of any significant size or being well adapted as later lineages.

            I can see it being a possibility that the diversity of life in the ocean might have been a bit lower due to lack of coastal areas compared to now. There were probably parts of Panthalassa that were more than twice as far from any land as the most isolated places today, though granted we have no idea of how many islands dotted the thing and it is likely to have been a substantial number. A few larger ones like Wrangellia were absorbed onto a continent but most were not so lucky. I guess this sort of thing will be an unknown question unless an ocean currents map of Pangea exists. But I imagine that a Hawaii of the time, many thousands of km away from Pangea, would have been an extremely exotic place. This is especially as the biggest flying animals were insects, birds today likely increase the colonisation rate of remote islands by multiple orders of magnitude, and even then it is estimated Hawaii was only found by one new species per millennium on average until we showed up. So maybe even large islands would be colonised by just one or maybe two plants and a few insects, possibly also marine arthropods returning to land as crabs do very often today. So many of these lost worlds, gone without a trace 🙁

          • The biomass in the oceans is not a straightforward calculation. Much of the ocean is an unproductive desert. For animal life, the sea does pretty well. For plant life, it doesn’t do anything while that is by far the dominant biomass on land. Bacterial biomass is uncertain. To me, it seems that biomass has exploded since life came to live on land. I once put some numbers in the CO2 post:

          • Thats right most of the ocean is a watery desert, I been in Big island of Hawaii many times, in the middle of the North pacific Gyre thats the worlds most nutrient poor ocean. That means water visibility in Hawaii can in some places be 85 meters! just outside the islands, nowherelse on the planet is there souch clear blue beautyful ocean. It was magical sight specaily the Kona Side, completely dark indigo blue with light blue shallow areas in the water. It was an awe striking sight to see souch a clear blue ocean, infact its one of the highpoints of the Big island togther with Hawaii Volcanoes National Park and the 11 climate zones. Its so beautyful that ocean awe stunning and its like swimming in an destilled swimming pool in some points on the Big island.
            The low nutrient content of the water forms the blueness that we find so very alluring

            Hawaii being the most isolated is also the most nutrient poor ocean and also the bluest., its quite alot clearer than maldives even, in Google Earth Hawaiis insane clearness is very visible

            Hawaii is extremely nutrient poor, yet biodiversity is very high, as the lifeforms have evolved to live in ther worlds most nutirent starved ocean. There is lots of stoney corals of one specific genus, and yellow tang fishes are very common. I have swimmed many times there I call it liquid air

            Here in Baltic Sea visibility is only half a meter and just centimeters near the coast 🙁 green crap soup too much nutrients

          • Its awe stunning just how clear the waters are in Hawaii
            Just outside Big islands west coast you coud see a shipwreck even if its 100 meters down, as a dark hazy blue shadow, still the avarge visibility some distance out the coast is 67 – 75 meters I think

          • Here in Baltic Sea its green pea dog poop soup, with productivity so very high in the waters that its un – attractive to swim here even, its all the countries around it with their agicultural runoff and industrial runoffs that makes my shallow ocean into a terrible mess. Baltic Sea turns dark green even a meter below the surface so I never swims here, the water quality is simply not good enough, even if there is lots of oxygen produced from the algae mess. Baltic Sea is the worlds most polluted over – fertilized ocean, the sea coud be lost soon because of eutrophication

            We dont have Hawaiis Hyper -Oligotrophic beauty

            the old Pantalassa must also have been the ultimate watery desert, perhaps even more so than Hawaii I guess

    • PETM also had over 100 F Sea temperatures. Souch hot seas will evporate enormous ammounts of water increasing humidity and cloud rainfall alot in the world, as well as fueling near hypercanes.

      Pangea maybe was dry even with souch warm humidity since it was a larger landmass

      But most past supergreenhouses been wet and forested, the Equator will become an unlivable 40 – 50 C wet sauna If cO2 gets that high again. Greenhouse Equator was warmer than todays Equatorial, so the ”cool tropics paradox” is acually wrong

      Past Supergreenhouses must have had a quite cloudy Earth because of all water vapour forming clouds, the cloud coverage being much higher than today

      • Jesper, while there is more water vapour due to incresed evaporation, there is also likely greater climate variability. One hallmark of hotter climate is that there is greater volatility in the climate itself, leading to more monsoonal type behavior.

        So while on average, there may be more water, the reality is that there may also be longer or more drastic dry seasons in many areas, coupled with excessively hot weather.

      • Antartica icesheet have a huge drying effect on the worlds climate, I guess as long as it exist we will have deserts or dry areas, its formation 35 million years ago because of dropping cO2 caused a huge change on the other continents

        Australia was paticularly hard hit by the glaciations drying effect, went from tropical rainforest to Savannah in just a few million years and in the late pliocene it was beginning to dry out competely and become a huge series of sand dunes during the Pleistocene Ice Ages

    • Future volcanic supergreenhouses in geology terms will be even worse than previous because the Sun is brigther now and CO2 is because of that even more warming now than before

      A New CAMP or Siberian Traps in 300 million years may kill the biosphere with more greenhouse per cO2 than during Permian

    • A Siberian Traps today is worse than the Permian because cO2 is more powerful now with a brigther sun

      Kind of scary that humans release perhaps about as much as a Mega – flood basalt

    • Many mass extinctions are far away from our times and it is difficult to meaure the whole timescale from the beginning to the end of a single mass extinction. There may have been a evolutionary decline of certain species even before natural disasters occured because some biological developments were dead ends. Added to this the continental drift and climate changes by this may easily change environmental patterns and let some species die which previouly had prosperous ages.

    • That coud be the chase but most supergreenhouses been rather wet with No deserts, but Pangea Greenhouses had at least some deserts yes as moisture dont get far inland

      But it was after Pangea broke up everything became superhumid, and remained so all way until the Late Eocene cooling and drying and became super dry during the Pleistocene Ice Ages

      I can just imagine how dry Pangea must have been during the Permian and Carboniferus Ice Age, must have been rather marsian with cold deserts covering most of the land the Permian Ice Age lasted most of that epoch

  21. Grimsvotn is having notable seismic uptick and on a ironic note, it looks like the deformation has stabilized over the past year with potential deflation on some spots. Thoughts?
    CCN is having it’s most intense swarm so far as magma is accumulating at shallow depths and this magma is either slowly rising to the surface or struggling against a plug.(need more seismic data to confirm) The longer this swarm goes on, the more and more likely an eruption is.

    • The CSM graph is still going steep, bit less as some month back, but still…

      Was going to mention Greip has been a bit dormant lately, but there she is.

      • Grimsvotn and Iceland isn’t my area of expertise, but I am dying for an update on Grimsvton

  22. Tromen has a variety of magmas from basaltic-andesite to rhyo-dacite. Those volcanoes are exciting, because you never know which magma will come next, and the eruption style can change from eruption to eruption. Mount St. Helens is an example of a volcano which does magmas from basalt to dacite. It did hawaiian lava flows 1700 years ago with lava tubes and it did andesite lava domes and flows on other occations. One of those andesite lava caused the disastrous blockage 1980.

  23. Pingback: Laguna del Maule. An explosive rhyolite ring volcano. | VolcanoCafe

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