The Snake river

Shoshone Falls, Snake River, Idaho

Shoshone Falls, Snake River, Idaho

Every child likes rivers. The constantly changing surface, the movement, and of course the water are irresistible. From floating sticks to building dams, they offer entertainment and learning. But rivers are also important to geology. Rivers feel the lay of the land, accurately showing the tilt. They cut away the surface and reveal the rocks below. And their sediments build the land, as well as show what is upstream. A lot can be learned from flowing water.

The Snake River is a good example. It bends its way through volcanic history, traversing a rich landscape, from the alpine plateau of Yellowstone to the arid lands of Idaho, until its end at Burbank (near Kennewick), Washington where it meets its superior, the Columbia river. Everywhere it flows it reveals a deep geological history, of plumes, rifts, and even lost island arcs. Mountains obstruct the passage in places, but elsewhere the river flows through wide plains. Nowadays, dams have added their obstructions, more of a problem for the salmon than for the water. The river begins in some of America’s youngest mountains; as it flows towards the Pacific, it cuts through progressively older rock. But even the aged rock isn’t old. This is a dry, wild, young land, build by massive eruptions and shaped by biblical floods. The river is recent; it seems out of place in this semi-desert.

The Snake river. Source: Wikimedia. Click for full resolution

The Snake river. Source: Wikimedia. Click for full resolution

Although recent, in a way the Snake river began before the landscape. It follows a patchwork of pre-existing channels, formed by older rivers, which were slowly captured by the growing Snake. The river evolved with the land, with uplift and tilt even changing the direction of the flow. This is a river as could have been devised by Escher.

For those who like statistics, the Snake river is over 1700 km long, and typically discharges 1500 m3/s, the 6th most voluminous US river. If you like history, the many different names of the river come from the diverse native communities who depended on it. But for volcanoholics, this is the river that trailed the Yellowstone hotspot.

Colombia river basalts

A dam across the Snake river in Washington. Note the layering of lava flows in the hills. Dams were natural for the Snake river, due to lava flows

A dam across the Snake river in Washington. Note the layering of lava flows in the hills. Dams were natural for the Snake river, due to lava flows

The geology begins at the end. Between the river mouth at Burbank, Washington, and Ontario, Oregon, where the river defines the Idaho-Oregon border, the Snake river flows over the Colombia river basalt, the youngest flood basalt on Earth. Most of it was erupted within a 1-million year period, 16 million years ago although some residual volcanism continued until 6 million years ago. These were not a few isolated lava flows: the never-ending outpourings covered an area the size of the UK to a depth of a kilometer.

The Snake river follows the fissures which created the Colombia river basalts and which erupted huge, sheet-like flows. No hidden lava tubes here! The wide lava sheets reached the Pacific Ocean, hundreds of kilometers distant, and continued on the ocean floor. Some 300 separate flows have been identified, each on average having a lava volume of 500 km3. Each separate flow appears to have been short lived: the rocks show that there was very little cooling along each sheet. To avoid cooling, each flow could not have lasted for more than one week, and the flow must have laminar, not turbulent. To get to the ocean in that time, the lava would have moved at perhaps 20 km/hr: if people had been around, they would have seen the approaching lava front, 50 meters tall and coming twice as fast as they could run! But this model is disputed. Other scientists argue that the flows could have taken years, in spurts, where the real flow occurs underneath a solidified layer with break-outs at the front. The large depth of the flow could have kept the interior hot and flowing. In the fast model, each individual flow would have been as large as 20 Laki’s, and erupted 20 times faster, at a rate of 50km3 per day. Toba was worse, but there it happened only once. In the slow model, each flow would have been only a few times worse than Laki but continuing for far longer. As real eruptions tend to show decaying eruption rates, with much of the lava erupted early on, the Colombia flows may have combined aspects of both models. Toba has shown that the fast model should not be discounted.

300 flows over a million year amounts to one every 3000 years, and gives an average eruption volume of 0.1km3/year. This is not far from what Iceland produces. However, these numbers are only an average – at times the flows followed each other much more rapidly, perhaps less than 100 years apart. And just the sulfur in each eruption could have wiped out life hundreds of kilometers away. The devastation is hard to imagine.

 The Colombia flood basalt. Source: Click for full resolution

The Colombia flood basalt. Source: Click for full resolution

The Colombia river basalts are among the first outpourings of the Yellowstone hotspot. The Yellowstone hotspot is currently near Yellowstone. It was stationary while the continental plate drift west-southwest. At the typical rate of 4 cm/yr, 16 million years ago the hotspot would have been underneath Oregon, 600 km southwest of Yellowstone. This puts it near the Oregon-Nevada border. The Snake river flows 200-400 km north and east of there. At such distances, was it really the hotspot triggering the local eruptions?

The oldest eruptions are from southeastern Oregon, but flooded a huge area, including that of the current Snake river. The eruptions which formed the Colombia plateau, further north, occured between half and one million year later, and covered the northern extend of the older flows. The flows became progressively younger towards the north. It seems volcanism traveled north, away from the hotspot.

The region show swarms of dykes, roughly aligned north-south, and many close to the Idaho-Oregon border. The swarms don’t quite point in the same direction: there is a bit of a rotation. Allowing for continental motion. it is possible to identify a centre from which the dykes radiated away. This central spot turns out to be Steens Mountain, southeast Oregon. This is also the location of the oldest dated flows, at 17Myr. It seems that Steens mountain is where the Yellowstone hotspot first erupted on the scene. Shortly after, 15 million year ago, a number of large caldera eruptions occured to the south, around McDermitt on the Nevada border.

 Steens mountain, southeast Oregon, place of the first place of the Yellowstone hotspot.  Image from Oregonlive

Steens mountain, southeast Oregon, place of the first place of the Yellowstone hotspot. Image from Oregonlive

So what happened? One model is that the mantle plume first came up underneath Steens Mountain, generating multiple magma chambers. The plume and the early eruptions build up a large bulge on the surface. The weight of the bulge pushed the magma outward: it followed a ‘downward’ trajectory (in so far as that makes sense underground), a path of least resistance. The Holohraun magma did the same: at each point the dyke followed the steepest contour of the land above. The Steens magma chambers thus migrated north and caused eruptions far from the original source. The Snake river still follows the path formed by these dykes. In this region, the rivers originally flowed towards the south. But the uplift from the hotspot reversed the incline of the land, and the rivers stopped, and began to flow the other way.

While the main volcanism migrated north, eruptions also started to move towards the south, forming the McDermitt calderas, and west, with the most recent outpourings as fast west as next to the Cascades. The latter is opposite to the track of the presumed hotspot! How is that possible?

Camp and Ross, in 2004, suggested that the thick lithosphere underneath Idaho stopped the plume head in its tracks. The plume itself is a fairly narrow channel; underneath the crust it stops and widens, forming a bulbous head much wider than the channel that fed it. This wide head was sheared off from the plume channel underneath by the deep Idaho crust. Tied to the crust, the head was forced to follow the continental drift. The plume and the head were now moving in opposite directions.

V. Camp and M. Ross, 2004, Journal of Geophysical Research, vol. 109, B0820

V. Camp and M. Ross, 2004, Journal of Geophysical Research, vol. 109, B0820

Hells Canyon

The Snake River in Hells Canyon. The dark rocks on top are the  Columbia river basalts. The light rocks underneath are the older, accreted   terrain. Source:

The Snake River in Hells Canyon. The dark rocks on top are the Columbia river basalts. The light rocks underneath are the older, accreted terrain. Source:

Along the Idaho-Orgeon border, the Snake river passes through a high plateau, which reaches far above the level of the river. The river does not go around it, as other rivers in the area do, but enters a deep canyon which disects the plateau. By some measures this is the deepest canyon of the US. The Snake river runs more than 1.5 kilometer below the level of the plateau, and compared to the mountains east of the canyon, the depth is almost 2.5 kilometer. 80 kilometer long, 15 kilometer wide, and 500 meter deeper than the Grand Canyon, this is Hells Canyon, inaccessible, and roadless.

The high plateau was formed in the flood basalt epoch. The canyon slices through this, down to the much older landscape which the flood basalt covered. Originally, this was the west coast of North America. About 120 million years ago, a volcanic island arc accreted on to the continent, extending it to the west. The Colombia flood basalt covered an ancient, volcanic landscape, now uncovered again by the erosion from the Snake river. Several dams have been build in the canyon, harvesting hydroelectricity from this monument to eroding lava.

Western Snake valley and Lake Idaho

In western Orgeon, the Snake river follows a low plain, an old rift valley or graben, from about 17 million years ago. The river flows close to the southwestern edge of the 50-kilometer wide valley. The valley diverges from the track of the Yellowstone hotspot, turning towards the northwest. Only at the eastern end of the valley does the Snake river join the central track of the Yellowstone hotspot. The graben formed when rising heat from below pushed the crust sideways, extending it. The central area dropped down in response, forming a rift valley. In a less resilient land, perhaps it would have split the continent. But in Idaho, no chance of that. Eruptions and a layer of sediment over a kilometer thick covered the valley and surrounding lands, but the valley is still here. The last eruption was less than 1 million year ago. The valley is still subsiding, in response to the loss of the heat from below. Why no flood basalt here? Perhaps the hotspot took too long to reform its magma chambers, after losing its head. Or perhaps the much thicker lithosphere here only allowed a little magma to travel through.

Volcanic eruption started explosively, rhyolitic, 11.5 million years ago, followed by basaltic eruptions 7-9 million years ago. A second phase of basaltic volcanism happened much more recent, 2 million year ago. Later, alternating layers of sediment and basalt formed. The vents include maars, cinder cones and shield volcanoes. The shield volcanoes are 200-300 meter tall and fairly steep, suggesting viscous lava. Most flows came from the edge of the rift and flowed towards the centre.

10 million years ago, Hells canyon wasn’t deep enough to drain this valley. The Hells canyon river, not the modern Snake, instead flowed towards the south and drained into the valley. Large lakes formed, eventually becoming one huge lake, extending to close to Twin Falls. This was Lake Idaho. Perhaps 2 million years ago, it first began to overflow into the deepening Hells canyon. The result was a biblical flood. It deepened Hells canyon and flash erosion widened it. This widening was completed by the Bonneville flood, 15,000 years ago.


The Bonneville flood came from Utah. During the ice age, a huge lake had build up, dwarfing the Great Salt Lake. When the dam gave way, a flood came, north, entering the Snake river valley, and created the 200-meter deep Snake river canyon, formed the Shoshone falls, and crashed through Hells canyon. At its peak, the flood flow was a million m3 per second. Sediment from this flood covers much of the Western Snake valley, all the way to the mouth of the river.

The Eastern Snake Valley, the great American rift and the Craters of the Moon


Snake river canyon

Snake river canyon

Beyond Twin Falls the land begins to rise, and the valley now closely follows the hotspot track. It is no longer a graben but became a valley because of the weight of volcanic rock, perhaps aided by the emptying and cooling of the magma chambers below. The volcanism is overall a bit younger than that of the western valley although it started at the same time or a little earlier. Basalt is everywhere. There are also five major rhyolitic domes: Big Southern Butte, Cedar Butte, Middle Butte, Unnamed Butte, and East Butte, but these are young, from within the past million year.

The eruptions started as massive rhyolitic explosions, forming five overlapping calderas. Rhyolitic magma is silica-rich, and form from melted crust. In the eastern valley, there is a deep layer of rhyolite (in places 4 kilometer thick), with a 1-2 kilometer layer of basaltic (silica-poor, mantle melt) magma on top, showing that both types of eruptions occured, in that order. As the conduit through the crust became wider, the mantle magma was able to reach the surface without requiring to melt more crust. Underneath the entire valley is a sill of intruded basalt, 10 kilometer thick and 90 kilometer wide.

A lava river in the V-Craters of the Moon

A lava river in the Craters of the Moon

East of Twin Falls, on the northern side of the Snake river plain, are three complex lava fields, together called (slightly misnamed) the Craters of the Moon. They were formed in a series of 8 eruptions, between 15,000 to 2,00 years ago. More than 25, often nested, cinder cones dot the desolate landscape, with over 60 individual lava flows. Each eruption started with gas-rich explosions, building the cinder cones, becoming effusive as the gas ran out. The southern-most flow, closest to the Snake river, is the Wapi field, a shield volcano that formed from a single eruption 2300 years ago. The volcanic activity here is dormant, but not dead: new eruptions are likely within the next 1,000 years.

The rifts of the Craters of the Moon run SE to NW, perpendicular to the Snake river plain, and clearly have a distinct origin. The orientation is the same as that of the largest geological feature of North America, the Great American Rift. Also called the Basin and Range Province, it runs from Mexico to Canada and covers much of the mountainous west with series of flat, low-lying basins and narrow, steep mountain ranges. Famous Death Valley is one of them. The basins are due to crustal extension. The volcanism along the Snake Valley plane is in part due to this extension. The Craters of the Moon are one expression: crustal extension in one direction, crossing a crust weakened by a passing hotspot are a dangerous combination. The western Snake valley, Hells canyon, and the Colombia flood basalts fissures all follow this orientation.

Teton Mountains

Ansel Adams: The Tetons and the Snake River (1942)

Ansel Adams: The Tetons and the Snake River (1942)

The Tetons are perhaps the most impressive mountain range in the US. One of the ranges of the great American rift, steeply rising more than 2 kilometer over the surrounding plains to over 4 kilometer height, they form an immense barrier, just south of Yellowstone. The Snake river runs along and around the mountain range, flowing into and out of Jackson Lake, one of the most scenic locations in the US. Here is paradise, of the overwhelming type. The Teton mountains formed along an active fault, with uplifting on one side. Although quiescent in recent times, the fault is subject to large earthquakes, but it is not volcanic.

The Teton mountains began to form 9 million years. Jackson Lake fills a basin next to it, making it a fairly typical structure for the western US.



Going up the river, we finally come to the end, its current beginning. Yellowstone is a wonder. Over half of all the world’s geysers are here, powered by the modern Yellowstone hotspot. The hotspot may not have found its last resting place, but it has lingered here, even in its current phase of quiet creating an unworldly landscape. The hotspot has uplifted the land, and captured the continental watershed which originally was much further west. On the east of the divide is the Yellowstone river which carries its water to the Gulf of Mexico. The Snake river, starting in the south of the park only 5 kilometer from the Yellowstone river (which starts far to the north), feeds the Pacific.

The hotspot has done immense damage here. Massive eruptions took out the heart of the region, leaving a broken ring of mountains surrounding the plateau. Three times the world exploded, 2.2, 1.3 and 0.64 million years ago, each eruption perhaps lasting only days or weeks. Numerous smaller eruptions added their mark, from rhyolitic eruption to basalt depositions. The eruptions followed a cyclical pattern: slow uplift as the magma chamber build, with minor eruptions, the explosion followed by caldera collapse, post caldera eruptions, and resurgent doming within the caldera. At the end of the cycle, volcanism ceases and the geysers become the main outlet for the magmatic heat underground. After a period of quiescence, the cycle begins anew. The cycles may have finished now. Perhaps in a few million years the hotspot will pop up further east.

The Snake river in Yellowstone National Park. Source: Daniel Vorndran (Wikimedia)

The Snake river in Yellowstone National Park. Source: Daniel Vorndran (Wikimedia)

Hotspot or not?

The Yellowstone hotspot, with its massive eruptions that repeatedly devastated a continent, is legendary. Still, its existence is not universally accepted. The evidence in favour of a hot spot is twofold. First, the large melt volumes and the fact the region has been pushed up by kilometers shows the effect of heat from below. Second, the linear progression from west to east shows the effect of the continent traversing a stationary spot. This is strengthened by the fact that the distance between this spot and Hawaii has remained the same – as the Hawaiian spot is known to be deep and stationary, it suggest Yellowstone may be too.

 The hotspot trail and its calderas. From  this paper . Click to enlarge

The hotspot trail and its calderas. From this paper . Click to enlarge

But this has not convinced everyone. There are three basic problems with the hotspot model. (1) Along the Snake river valley, the basaltic eruptions are about 2 million years after the passing of the hotspot; (2) Much of the volcanism is far to the north of the hotspot track; (3) The seismological evidence does not clearly show a deep plume. On this last point, there is agreement that there is a warm region here, but how deep does it go? Underneath the western US lies a subducted plate, the Farallon plate. Seismological mapping has traced the remnant of this cold plate, but little trace of a deep warm bubble penetrating this plate has been found underneath Yellowstone. The heat maps are shallow. It is possible that the plume is not in fact underneath Yellowstone, but is further west, deflected at shallow levels towards Yellowstone by the sinking plate. There are indications for a deeper plume 200 kilometer to the northwest of Yellowstone.

And why did the hotspot and the great American rift, which should be unconnected events, start or intensify at the same time, 17 million years ago? Where was the hotspot before this time? Edge convection related to the Farallon plate could explain both. But to me, the Ayes have it and the case for the hotspot is too strong to be dismissed. The hotspot was affected and perhaps energized by the great rift. In fact, the extension of the first flood basalt outpourings to the northwest follows the orientation of the rift. Elsewhere too, the northwest trending rifts provided pathways for the magma to travel long distances. The rift feeding Holohraun may provide a good model for this. But the heat came from below and the magma from the mantle. Still, the depth is disputed, the origin unclear, and immovable opinions make the arguments as heated as the ground below.


The Snake river, on the trail of the hotspot, follows some of the most impressive and geologically fascinating scenery in the US. It is a young river, which took its current shape only within the past million year, stitching together beds from many pre-existing rivers and flood beds. As the hotspot uplifted the land, the river beds tilted and the Snake, while following the hotspot, started to slither west. The river is not yet finished: when the hotspot moves again, so will the Snake. At that time, as the continental divide follows the hotspot to the east, it may capture the Yellowstone river. The Snake river is an ever evolving, living heritage. Entertaining, educational, and fascinating.

/Albert Zijlstra

173 thoughts on “The Snake river

  1. Thanks for this great american time adventure! I had to read several times to capture all exiting details! Hot spots, if they exist, are realy strange phenomenons!

  2. A very large earthquake in the South Sandwich islands. At this size tectonic, but it is a highly active region with many frequent volcanic eruptions. An earthquake tis size could easily trigger eruptions over the next few days. It is winter there and probably noone closer than South Georgia. Only satellites could pick it up.

  3. Wow Albert! I was engrossed with this and learnt so much – thank you very much for a great read. It must have taken you a lot of work to put it together.

  4. Thank you Albert – that’s a fascinating article. Sheeee-it – what’s going on? You publish this great article at the same time as VH publishes a feature on Craters of the Moon! And just a few short weeks before I’m going to the SRP/Cr-o-t-M (while desperately trying to understand what I will see). Serendipity!

    • That was pure serendipity! And I must admit not having seen the VH article – I do normally read their posts. Great brains (VC & VH) think alike?

  5. I Live in that big, high and lonesome country.
    Informative, and accurate. I have flown the Snake
    drainage many times doing snowpack flights with
    the US Army Corps of Engineers and fighting fire
    in DC-6/7 airtankers. Two minor things-one the the
    Snake meets the Columbia at the town of Burbank
    named for the same Burbank that the town in
    California was. Two,Ontario is on the Snake but in
    Oregon. Kennewick is just slightly north of the confluence,
    on the west bank of the Columbia.
    Here is a PDF of the local Grande Ronde Basalt flows
    and others…
    Great job.
    Here is one of the my favorite Cowboy poets about the feeling
    of living (and working ) in the “big High and Lonesome.”

    • Another thing the Snake rive got its name from the Shoshone
      Indians.My wife and I have a good friend who is a Shoshone went to a wedding of her son the other day to honor her, we wore our Native american stuff, my beaded belt with my Pop’s
      Indian themed buckle and wife wore her Turquoise. She wore
      her dancing outfit and buckskin jacket.. Sacajawea was a
      Shoshone-the guide for Lewis and Clark..
      Here is a bit about the Confluence and the history.:

      • FYI, someone whacked the ex CEO of Patriot Coal. Gentleman by the name of Hatfield. How’s yer alibai? (They’ve already made an arrest btw… not a mccoy)

    • Thanks for the corrections! I fixed them. Comes from relying on sketchy maps.

  6. I love what some call synchronicity !
    After a long hard day in my shop yesterday I came home , kicked off my shoes and sat back to read the article here. (Thanks Albert, and ALL contributors. The work put in is plain to see).
    As is unfortunately my idiom, I slipped into a series of narcoleptic sleep attacks, whilst occasionally waking, and re-reading to understand and keep up with the material about the river and these flood basalts…and I remember (I’m not re-visiting it as thought association tends to bring on further sleep attacks) reading about some huge outburst of water…which may or may not be (really sorry about this…) the same event that was related to the sequence of events leading to the formation of the Great Lakes.
    Such is the way of things with narcolepsy I’m afraid…. tenuous links formed in hypnogogic transient states tend to merge things into something which is often only a vague and distance relative of empirical reality..
    But sometimes this can be interesting and creative.
    Eventually I realised that the episode was not going to pass, so I called it a night.
    This morning whilst waiting for the rest of the household to rise, I channel-hopped until I stumbled across a re-run of a Time Team (British archaeology-based tv) special on the British tsunami of circa 6000bc ..
    This focussed to a large extent on Dogger Land, which is now the submerged area of the North Sea, Dogger Bank. The presenter explained how this large tsunami swept through the area, and I must say that it sounded very similar in many respects to the way in which water swept across vast tracts of Northern USA .
    It seems it is mooted that the cause was slippage of a submerged bank of sediment off the coats of Norway.
    Ok…sorry for the ramble, but here’s my point.
    I think a great many people are now aware of El Cumbre Vieja, and (correct me if I’m wrong here), I believe that researchers are now actively looking for similar potential hazards around the world.
    Has anyone looked for unstable banks of sand, gravel and so forth? Because it seems to me that this event probably rates as “mega” tsunami ?

    • Cumbre Vieja is not considered a major problem at the moment, but landslides are an important cause of local tsunamis and should be taken seriously. They are not easy to predict though (unless opposite a calving glacier – than they become pretty predictable). Any steep-sided volcano near water is a potential danger. It was one of the reasons for selecting Chiltepe in Lake Managua as number 2 of the most-dangerous-volcanoes list. Note that the landslide does not need to begin above water: an underwater slide can be equally dangerous.

  7. Amazing to learn so much about what is essentially “my backyard”.
    Thank you immensely for this report and your analysis.

  8. Thank you very much, Albert. I feel the “Snake River” name should carry all the way to the Pacific and the shorter “Columbia” should be the tributary, much like the “Missouri” is the larger of the two rivers joining and called the “Mississippi” downstream after the smaller of the two.
    Although it’s not a major tourist attraction, the immensity of the Craters of the Moons makes it worth a visit if one ever visits that region.

  9. I’ve noticed SakuraJima has been really quiet recently, even on the webicorders. It’s a bit interesting to see how there has been a much lower output since the seismic crisis occurred there a while back.

  10. Possibly of interest – there have been quakes recently in the Herdubreid region, which isn’t particularly uncommon. But what is slightly strange today is that the quakes are north east of the ridge and tuya, kind of in no man’s land. I’ve never to my memory seen any quakes here.

    • Would be interesting with some gps data from Herdubreid region. I wonder if there are any stations around?

    • Quakes around Herdubreid continue. From 25 km to 0.1 km deep. I have also watched the region for several years and cannot remember a similar pattern.

    • Quick plot, hope you can find your bearings but shows quakes in the area of curiosity, last 2 weeks in red, since Aug 2014 in black

      Great article once again Albert, now I know more about the Snake River, before it was just a place Evil Knievel jumped.

      • Thanks. very nice plot! Obviously quakes all around the place before. Pobably there were longer time periods between them so the pattern was not so easy to se.
        Were do you get the raw data from. Somewhere on IMO or do you captureand store continuously?

        • Wish I had a little more time to overlay on a map background but thanks 🙂

          IMO keeps a webpage and posts weekly lists

          One of the links gives a text list which I copy over to Excel, usually I wait a couple of weeks, they often correct or even add quakes not found on the automatics system

          I have over 50000 quakes on the spreadsheet

          • Hi.

            Why not use something like cartoDB, it provides plenty ways of visualize data, one of my favorites is heatmap. Queries are easy to set and to add data is almost copy/paste, since you already have in Excel, just upload or export to CSV and upload using CSV.

            Processing thousands of EQs only takes about 2/3 minutes.

            Usually i take seismic data from here:
   (Iceland Met Office does not update data)

            Some examples i made:

    • Earthquakes are not at all uncommon here, so what we’re seeing at the moment is nothing out of the ordinary.

    • It looks interesting on the close drums, having a double break feature. This could be just another quake M1.5+ occuring quickly after the M3.4 initial break. Also the initial break was not as clean, but for around 10 prior to it, a weaker tremor appeared, whixh could also just be the usual background activity. Will need to wait for IMO to full process everything.

      • Around 10 seconds.

        Forgot to add units after 10.

  11. Soon after, now a 4 minute long low amp tremor appeared, with the signal focused aroubd Bardy. Could be the glacier activity.

  12. All activity seems now on the SE side. There hasn’t been a significant earthquake on the NE side for 10 days.

    • And just like the other recent, shallow 3ish quakes this one is also followed by silence. Or are the seismograph sensitivity automaticly adjusted after a strong quake?

      • But not at the end: it seems a few km closer to the caldera centre than the usual NE/NNE cluster. Well inside the caldera. But that may still be updated.

  13. Japanese documentary (in English), It’s 28 min long.
    “The leading edge, science documentary – Is Nishinoshima’s eruption producing a continent”

    • Posted that too quick, it stops 21 min in, oh well, no harm done I guess.

      GL Edit Add: No prob. It’s a good video. I was at first skeptical that it was nothing more than hype about the island, but they answered the chemical issues about the rock. (high silica magma)

      As for the painting bit at the end with the plaster coated paper, using a base coat on the media is not a new practice. Typically for some canvas work, a titanium dioxide base coat is used to enhance the white that is available. The unique chemical change that occurs with the plaster base that produces a protective coat against oxygen was pretty neat.

  14. IanF, I enjoy your graph in the quakes northeast of Herdubreid.
    That region is a small fragment of a transform zone, you can clearly see the parallel faulting towards the northwest. I wouldn’t be worried about earthquakes there, I think they are caused by the tectonic movements, and eruptions would be very rare there.

    Bardarbunga and Grimsvotn: both are yes increasingly restless. An eruption could occur in one of them in soon. Bardar shows an area to the southeast with deep swarms. This reminds me of pre-2014 behavior.

    Grimsvotn has been showing earthquakes in recent weeks, whereas before it was mostly quiet. In 2011 it did the same before the eruption, weeks in advance. Could it be doing the same now?

    Interestingly connecting all the dots I start to think what if we see a repeat of Gjalp or something in that region.

    Also since Holuhraun, the volcano Oraefajokull has been experiencing almost weekly if not every few day earthquakes, whereas before it had at most a couple of quakes per year! It is a big increase in activity.

    • Great to have your knowledge of things Icelandic on VC again, irpsit.

      iirc, you’ve moved since the Bardarbunga eruption – I hope it’s gone well.

    • Thanks! There does seem to be a lot of activity at the moment, but it is always hard to know what will develop and what will die down. Carl’s overview on is well worth reading. Grimsvotn seems to be not quite active enough for an immediate eruption. i would expect a significant uptick before it goes boom. Bardarbunga, or any of the others – no idea. But with so much activity, a summer eruption at one of these does become more likely. (And dare I mention Hekla?)

      • Oh you can always mention Hekla… which begs a question:

        “Hekla is aseismic until a few minutes before an eruption” is an often-quoted saying. But just how true is it? I’ve seen a few small quakes right on the ridge of Hekla over the last year or so anyway. Maybe once a week or once every two weeks or something like that. Obviously nothing like the M2-3 quakes that are typically quoted as the immediate precursors of the rift opening but still… seismicity.

        Might be worth drilling and analyzing the data on that over a longish period – say the last three or four years – and looking for patterns; see if there have been any changes in behaviour there.

        • True… but the general idea is supported by Hekla 2000. Other quake sets are probably recharging events or are tectonic in nature.

        • From memory, micro seismic activity (not sure how that is defined) was detected in the weeks leading up to the last eruption. I think the group of scientists had setup equipment in the area which detected this activity. I’m not sure for how long this equipment was up and running, so this begs the question how long these micro quakes had been ongoing?

          Perhaps they happen all the time and the small quakes we’ve been seeing on IMO for the past year are actually BAU. It’s just that now there is better equipment (and more of it) to detect these smaller quakes which we’re lucky enough for IMO to share – we could be no where near an eruption.

          Alternatively, Lady H has just changed her pattern and now prefers a good, slow, run up. I eagerly await the first 2+ to see which way she goes. 😀

          I may have remembered incorrectly so anyone out there with a better memory than I, or access to the paper that talks about these micro quakes please feel free to chip in

    • I wouldn’t expect it, but I also wouldn’t be entirely surprised if there were an eruption of Bardarbunga and Grimsvotn during the same year.

  15. An interesting look. The dike or the “elbow” where the deep quakes appear, SE of Bardy, seems to have the activity move a bit southwardly. Perhaps magma at depth is traveling in the Grimsvotn fissure swarm toward Grimsvotn? 😀

  16. …”begging the question”…

    Off topic, but I hope no one will mind if I take on the role of local pedant for a moment or two.

    The distinction between raising and begging the question is helpful (like those between dis-/uninterested, and infer and imply), but fashion seems now to dictate that we ignore it.

    Here’s a brief refresher definition, along with some examples (taken from here:

    The fallacy of begging the question occurs when an argument’s premises assume the truth of the conclusion, instead of supporting it. In other words, you assume without proof the stand/position, or a significant part of the stand, that is in question. Begging the question is also called arguing in a circle.


    1. Erica: “How do you know that the bible is divinely inspired?” Pedro: “Because is says right in the third chapter of II Timothy that ‘all scripture is given by divine inspiration of God.'”

    2. Celibacy is an unnatural and unhealthy practice, since it is neither natural nor healthy to exclude sexual activity from one’s life.

    3. Thoughts are not part of the physical world, since thoughts are in their nature non-physical.

    4. Happiness is the highest good for a human being, since all other values are inferior to it.

    5. Of course smoking causes cancer. The smoke from cigarettes is a carcinogen.

    6. Prosecutor to defendant: So how did you feel when you killed your wife?

    7. This whole abortion debate about when human life begins is ridiculous. We should be thinking about the rights of the baby.

    8. John: “Why didn’t you include Lorena’s poetry in the student publication?” Anne: “Because it was judged as not sufficiently worthy of publication.”

    9. People who deny the truth of Marxism are simply dancing to the tune of their capitalist masters, as Marx understood so well.

    10. The rights of the minority are every bit as sacred as the rights of the majority, for the majority’s rights have no greater value than those of the minority.

      • I hope you’re not begging the question as to whether agreeing to disagree is an option 🙂 🙂 🙂

    • Most of your examples do not involve a question.. Begging a question can be used for a question on the starting point of the argument, and that is very close to raising a question: begging a question is used for raising a question related to the beginning of an argument. So a study on the motion of the locus of the Bard’s earthquakes can raise the question how this locus will continue to develop in the future, or it can beg the question what is causing these earthquakes in the first place.

      Arguments/reasonings can be settled by detailed questioning (as is stilll the case in PhD vivas), or they can be subject to debates (popular in anglo-saxon cultures). Begging a question is used for different things in these two approaches.

      but can I ask whether the possible southward movement of the elbow is related to the depth at which the quakes occur?

          • Under further consideration, I have determined that the question is still is there. So, has a question been asked or should it still be considered a request? I am begging the question

          • I’d say that Down Under’s diagram (and the earlier one by Ian F) certainly raises some questions, and I am glad that Albert has asked them.

            I am begging the answer 😉

      • I agree, not all the examples given on the website I quoted from (obviously) involve a question. But that is where the phrase “begging the question” can be a bit misleading as a translation of the Latin original = “petitio principii”. There’s an well-informed etymological discussion here:

        However, if we take the Latin to be accurately translated as “Assuming the initial point” or “postulating the beginning”. Then the fallacy of petitio principii in the examples given is more obvious. To take one of the examples from the website: “Thoughts are not part of the physical world, since thoughts are in their nature non-physical.” The “principium” that is being assumed here is that “thoughts are not physical”, when it is precisely that that has to be established if I am to be warranted in asserting that “thoughts are not part of the physical world”.

        I’m not sure I understand your distinctions and the example in your first para, but I think we’d agree that there’s a difference between someone’s raising the question of why Bardarbunga erupts and someone else’s begging the question if they were to answer “Because it’s a volcano”.

        A slightly different example of petitio principii would arise if, in a PhD viva, you (as an examiner) raised the question with me “Why did Bb erupt in 2014?” and I answered, “Because the dragons were restless”. In this case, I’d be begging the question of the existence of dragons. And presumably you would not fail me if, under close questioning, I were to prove the existence of dragons in the bowels of Bb, and to prove that they stirred from quiescence on August the 16th 2014. QED!!

        • Like when Bart and Lisa prank called Moe’s bar and asked for Al Coholic. Moe kept on asking if an ‘Al Coholic’ was in the bar and if they’d answer the phone please. (QED. Begging the question)

  17. Thanks everyone for the warm welcome.

    All is fine. I have left Iceland in early 2015, right during Holuhraun but not because of it 😉

    I will miss the volcanoes from Iceland!!! But earlier this year I travelled to Indonesia and had my good dose of volcanoes.

    Many of them steaming. Climbed a few, but while trying to seek an ongoing eruption there (there were a few at the time), I had bad luck.

    First I travelled to Flores, as it was in my plans, and Egon was right in imminent eruption warning, but nothing happened, despite the fact I was sleeping just 20km away.

    Second tried to catch the eruption of Mt Bromo, in eruption between Dec 2014 to Feb 2015, but when I travelled there the eruption just terminated 3 days earlier! Still, the plume was very thick and beautiful to photograph, as I hiked to 2km when gas became unbearable.

    Lastly I tried to catch Dukono. And I said “this one I will not miss, as it is always erupting since the thirties” .But while I took 3 days to stay at an village just 10km away, the weather was unbelievable overcast and I could only barely see a bit of a plume through the thick clouds one evening. Two tourists however went camping at the crater and had an amazing sightining!

    I couldn´t wait more because the days following would have the total solar eclipse which was just some 100km south (the eclipse was a unique unmissable event, but eruptions are nothing new for me). Guess what? Right after the eclipse, I catch a major eruption episode from those 100km south because the weather was clear, and that was unusually large for Dukono.

    One last note, was that during my trip there, a M8.0 happened in Sumatra. But thankfully no tsunami ever happened, and I was unaware of it, as I was right in the coastal jungle of Borneo, when it happened, and on a boat.

    Despite the trivial experience volcano-wise in Indonesia, I had unforgettable experiences in which it regards the friendliness of people, the beauty of the landscapes and the incredible wildlife of the country.

    • Irpsit, so on which plate do you now reside? Where is your nearest triple junction?

      • After Iceland I had some time in the tripple junction in the Azores, visited the subduction zone between India and Australia plate,and now I am slightly north of the collision of African plate into the the Eurasian plate. I live in the Alps now. Nearby tripple junction is I think somewhere in Greece or Turkey, between African, Eurasian and Anatolian plates.

    • Thank you Albert for your writing!

      Irpsit – Good to see you are well!
      I am glad to see you are experiencing interesting things on your travels.
      If I remember correctly you were pretty close in your predictions regarding the Holuhraun event.
      I would be interested if you have any further thoughts on the current and future events in and around Vatnajokull.

      • What’s my thoughts?

        Well, to start I put things into the greater context. There is a cycle every 130 years or so, with increased volcanic activity in Iceland.

        Therefore I expect much more eruptions in Iceland, big ones, and also unexpected ones, and especially an increased in Vatnajokull activity and also a couple of rifting episodes.

        Holuhraun and Grimsvotn 2011 were two manifestations of this. As well as the events in Hamarinn in 2011, and the awakening of many volcanoes previously dormant, such as Kverfjoll, Tungnafellsjokull, Hofsjokull, Oraefajokull and also more activity in Askja and slightly more activity along the dead zone.

        I expect that we will see eruptions at some of these spots in the next 15 years. Kverfjoll is one of which I think it will erupt in the next few years (if so it would most likely be an explosive VEI2 or VEI3). My rationale is that this is a volcano that erupted regularly in the past, and after Holuhraun I tend to expect that it got under stress.

        Tungnafellsjokull is another possibility but less likely one (most likely it would be an efusive VEI1 of a small rift). A fissure around Askja is another guess.

        Then, I am pretty confident we will either see an eruption at Hamarinn or Thordarhyma, but unsure whether it would be just in the central volcano or a major rifting event.

        I see with interest the pick-up of activity at Oraefajokull. Despite that I still think we might still be years from it, the fact that activity is becoming almost daily has raised my eyebrows a bit.

        I think also that we will see an eruption offshore in Reykjanes.

        The other two spots which I tend to pay attention to, is one north of Geysir, belonging to the volcano Prestahnukur and another south of Hekla (fissure near Vatnsfjoll volcano). I think we will see an eruptive fissure opening in the vicinity of Hekla.

        My guess for next eruption is one of these: fissure near Hekla, near Askja or in the southern or western part of Vatnajokull.

        • Guessing next Icelandic eruption is like Russian roulette.
          Very hard to say.

          Prior to Eyjafjallajokull 2010, that volcano was one of the areas in Iceland with the deepest quakes. Same happened prior to Holuhraun 2014. Even with deep swarms both in the caldera and north of Bardarbunga. What about now?

          (This rule does not apply to Hekla or Grimsvotn)

          So our answer is mostly with Askja, Katla, the area near Hekla and Torfajokull, Hamarinn, and vicinity of Bardarbunga.

  18. off topic – but is Down under around ? I seem to recall he’s the top weatherforcast modelling chap (?) was wondering if he had software recommendations 🙂

  19. Shallow earthquakes under Bardarbunga.

    Is there a possiblity ice (movement) is causing them? Or ‘just’ hydrothermal events?
    Does someone know what number on the M-scale ice movement can cause?

    Wednesday01.06.2016 10:55:28 64.654 -17.539 0.1 km 2.3 99.0 1.6 km NNW of Bárðarbunga
    Wednesday01.06.2016 08:46:18 64.683 -17.507 0.1 km 2.3 99.0 4.8 km NNE of Bárðarbunga
    Wednesday01.06.2016 08:44:18 64.661 -17.506 0.1 km 3.1 99.0 2.5 km NNE of Bárðarbunga
    Tuesday31.05.2016 21:29:22 64.674 -17.461 0.2 km 1.6 99.0 4.9 km NE of Bárðarbunga
    Tuesday31.05.2016 12:24:53 64.619 -17.447 0.1 km 3.4 99.0 4.5 km ESE of Bárðarbunga

  20. Wow – how that’s done is completely beyond me. Thank you.

  21. Ian. Thanks for the map.

    Now we can see which areas have been seeing deep earthquakes in Iceland (>14km depth), probably related to magmatic movements more than tectonics.

    These include:
    – Holuhraun dike
    – Tungnafellsjokull volcano or actually Vonarskard caldera (right next down to Bardarbunga caldera!)
    – Askja, slightly northeast, and also at Herdubreid!
    – Katla!
    – Reykjanes offshore
    – Tjornes offshore
    (to a minor degree, some quakes also at Kverfjoll, Oraefajokull and Torfajokull)

    So to answer your question, Ohr:

    Magmatic movements have occurred consistently in Katla, Askja-Herdubreid, Reykjanes and Tungnafellsjokull.

    I think these are the most likely volcanoes to erupt within the next 10-20 years (other than the rather asseismic Hekla and Grimsvotn and the already awakened Bardarbunga)

    Of these I am rather confident to see an eruption at Katla, Askja and Reykjanes, because I think the events at Tungnafellsjokull were mostly connected to the Bardarbunga caldera collapse.

    How would they be?
    – An explosive VEI4-5 eruption at Katla, statistically more likely to occur in summer, and with months of many more earthquake swarms like in 2011, but now deeper, and with rapid inflation (this was what missed in 2011)
    – A fissure eruption somewhere northeast of Askja. The magma is there, the tectonics have been greatly changed since Holuhraun. I think we only need to see a sequence of events similar to Hioluhraun, a couple of weeks of serious earthquake activity (or even quicker) and then an eruption, most likely efusive and like 1961. Askja was greatly awakened after its major eruption in 1875, so an eruption there is quite likely to occur again.
    – Surtsey eruption at Reykjanes or Eldey. Most likely begins suddently with a swarm of earthquakes, as we have no more data about it. Eruptions at that region have been quite common since settlement of Iceland, so I expect to see another one again.

    • Askja 1961 apparently showed major changes 2 weeks prior to the eruption, so this gives us plenty of time to book a flight to Iceland, except that the area is mostly very remote, and only accessible by jeep in July to September, or private airplane if weather allows.

      A small VEI0 eruption occurred in Reykjanes in 1926 but data is scarse about how long it lasted and how it was. A suspected eruption underwater occurred in 1966. Larger explosive eruptions occurred the century before in 1884 and 1830. Also an explosive VEI3 happened at same time as Laki in 1783. Eruptions have occurred once or twice a century on average and range VEI1 to VEI3, so small explosive to medium explosive, but one in 1226 was quite ashy and caused problems in south Iceland (a VEI4). All these eruptions occurred during periods

      Eruptions in Bardarbunga historically occurred regularlarly at Hamarinn area (Loki-Fögrufjöll) and at the Dyngjuháls ridge, which is 25-50km long, located west of Holuhraun, and both are where deep earthquakes occurred prior and after the Holuhraun eruption.

    • Going back to

      cbus05 30/05/2016 at 18:46
      “Possibly of interest – there have been quakes recently in the Herdubreid region, which isn’t particularly uncommon. But what is slightly strange today is that the quakes are north east of the ridge and tuya, kind of in no man’s land. I’ve never to my memory seen any quakes here.”

      Your memory serves you well

      If you focus on this area on the map you can really see how dramatically the pattern changes after the eruption takes place. Remember the Orange quakes are only 7 months total quakes (Jan 2104 to end of July 2014) and the blacks are 21 months worth.

      • I think it’s also somewhat interesting how much lower the seismicity is directly over the Herdubreid Tuya. It’s interesting to see how visible the quakes are over the ridges. I do somewhat wonder if there is a sizable magmatic region below Herdubreid which is playing a role in deadening the quake noise directly over it.

  22. Ian, it’s an amazing graphic. Thank you for that!

    I have analysed it.
    This is what I found:

    – Obviously after Holuhraun, Tungnafellsjokull caldera was awakened. But before there were two intrusion areas north of Tungnafellsjokull that went quiet. I wonder what happens next.

    – It is obvious that the magma of Bardarbunga jumped into Grimsvotn system, to where Gjálp occurred (deep quakes were already occuring there, after the 1996 rifting). Then, the entire area north rifted afterwards. Interestingly the area south of Grimsotn remains rather quiet, but deep quakes continue to occur at Hamarinn (connected to both central volcanoes) and at Thordarhyma. A new dike at Bardarbunga could travel next time in those directions.

    – A slight increase in quakes occurred towards Oraefajokull also. I start to think that Oraefajokull is a bit of a fracture zone. See the alignment of quakes, many deep, exactly perpendicular to the rifting zone. Same goes into the other direction, towards Tungnafellsjokull.

    – Everything remains similar at Askja, Krafla and Tjornes. I still see the quakes at Herdubreid mostly as tectonics, it seems to show as a fracture zone.

    -Earthquakes at Vatnsfjoll, south of Hekla, are now more localized. A dike could be moving upwards there. More data is necessary to check this.

    – More strinkingly is the dike, which no one ever mentions, at southeast of Langjokull ice cap. The earthquake focus is steady moving southwards, following the ridge and rift direction. I think this is a good candidate for a black swan eruption in Iceland.

    – Also similar activity seems to be occuring at Reykjanes volcano, from the southwest towards northeast, but less clear.

    – Katla: everything stays the same, but again -not ever mentioned – but there is two loci of activity besides the caldera; one is the cryptodome of Godabunga, the other is an area south of the caldera, outside the ice cap. This area has shown deep quakes at least since 2011. Katla can also throw a black swan. Because there are evidence of Holocene efusive fissures all around the caldera, also in the south.

    – Finally, a area west of Hekla, in the SISZ, is showing a more pronounced focus of deep quakes. I think this area could feature a large tectonic quake in soon, and it is a bit “overdue”.

    Any comments?

    • Great analysis Irpsit,

      I added 2013 quakes to the latest map

      What I noticed around Herdubreid, the quake pattern shifted from a North to South looking line to NE to SW line and stretched further North. Maybe due to changes in the stress field once the rifting started?

      The number of quakes surrounding Kverkfjöll seemed to drop off after the dike started

    • Thank you Ian – it is great to have a visual graph like that.

      The graph seems to indicate increased events in quite many areas and is actually quite exciting!
      Its almost mesmerizing to see Katla’s caldera reveal itself as you go forward in time.

      Irpsit, you do not let us down. I find your comment on the dyke southeast of Langjokull quite interesting – I had not noticed this event.
      Do you believe this is a dyke and showing magma movement but not of tectronic origin?

      • I think it could be a dike, because 1) most earthquakes are quite deep, to be just tectonics, and then the swarm has been occuring repeatedly in same spot, albeit with a small migration southwards over time.

        Also in Iceland tectonics and volcano phenomena are just part of same phenomena. Even in fracture zones like SISZ, where most activity is “tectonic”, one can find volcanoes and evidence of volcanic eruptions, although small ones. It is just because the plate movement is lateral, this gives little space for any magma movement upwards. In spots like Reykjanes, with a 45° angle in relationship to plate , most activity is also tectonics and only every few centuries do eruptions occur. In rifting areas, volcanic activity is more frequent and also more large-scale. Nevertheless most dikes never erupt, and just fill the void.

        Southeast of Langjokull seems to be a dike. But it has been confirmed that most plate movement is accomodated at the comparable latitude eastwards over Vatnajokull. As one progresses northwards, we find less plate movement over the west volcanic zone, and more over the east volcanic zone.

        • “As one progresses northwards, we find less plate movement over the west volcanic zone, and more over the east volcanic zone.”

          This suggests that there are two parallel rifts, both widening, and a rectangular chunk of crust between them that’s slowly turning counterclockwise, so the NW-SE diagonal of it stays touching the NA plate at its NW end and the EU plate at its SE end, while gaps widen between the NA plate and the SW corner of the rectangle, and between the EU plate and the NE corner.

  23. Scientists shocked to discover that Earth’s mantle is moving at TEN TIMES the rate we all thought… Massive changes in tectonic plates can happen ‘chaotically’

    A shocking discovery by scientists shows that the Earth’s mantle is moving ten times faster than originally thought, as reported by the Daily Mail. The revelation, which has taken researchers by complete surprise, came after the first comprehensive survey of the Earth’s mantle. In fact, it seems that the surface of the planet is literally “bobbing” up and down “like a yo-yo” on a million year scale.

    This bizarre and dynamic concept means ten times more activity than geologists originally predicted. So what does it actually mean?

    • First… “Naturalnews”? And the Daily Fail?? *facepalm*! 🙂

      Second… in as much as there’s any truth or real science in the reports it means that it’s taken a lot more mantle movement than we thought had occurred to have produced the observed magmatic activity over that few tens of millions of years. It does NOT mean there’s going to be ten times more activity in the future! The effects as observed in the geological record are facts; fixed points. Sea floor spreading occurred at rate ‘x’ as the Atlantic opened etc. If there’s any new data it’s about the amount of mantle activity that was required to make that happen.

    • This now looks more like hydro-thermal activity, both on von and dyn. Similar to what we have seen at Hamarinn prior to the flooding, tho in lesser extent, including the ocasional low freq spikes which are obviously not teleseism (limited to specific region and have a higher freq pulse with it), nor some deep quakes, since IMO isnt listing it, or doesnt bother with it. Bardarbunga is an active (relatively atm) volcano with bad digestion, so this kinda stuff is normal, even tho less likely to occur while the volcano is fully dormant. We are talking subglacial volcanoes here nonetheless.

      • To be clear, some low freq spikes are obvious and know teleseismic signals, but not nearly all. Esoecially lately, the low freq spikes are occuring with a moderate high freq spike aswell, and with a signal on the drums, very short and looks like a deep quake, unlike any teleseism Ive seen before, and its limited by signal to NW Vatnajokull, or Bardarbunga region to be specific.

    • The thickening of the signal, especially mid freqs like on the JOK station is also associated with hydro (thermal) activity.

  24. I’m a dog guy. I always have been. My first dog was a 75 lb Doberman named “Bull”. That was the name that my mom gave him since he would stand at a highspot of the hill up to the house and dare you to approach, until he knew who you were. Fiercely loyal, he saved my butt on more than one occasion when the neighborhood miscreant decided he needed some entertainment. Bull is long gone now, and I don’t have the needed yard space for a Doberman to properly stretch his legs. So, I sort of adopted this Half Lab half Pit that my grandson had. Actually, the adoption was the other way around, and since he is well mannered and as loyal as Bull, I insisted that the dog stayed when my grandson moved out for a while. Recently, I was down hard in bed for 4 days and that dog would not leave my side. At first, I just figured that he was on death watch, then I realized that he knew I was sick and was making sure that nothing could get to me with out him having something to say about it. From time to time I refer to him as “The Tooth Monster” since that’s all you see when he is coming at you out of the dark. Two glistening blue eyes and a large row of teeth. He is quite mild mannered though. This evening when I tossed a doggie treat in the air he, (being part Lab) instinctively went up after it. Upon landing the smallest dog took issue with him landing on his foot or tail and lit into the large dog. The large dog didn’t retaliate, he was just confused why this little furball was attacking him. I interceded before either one could get seriously ticked off and start meaning business. Essentially, they are both Betas. The Pekinese considers himself Alpha, but will capitulate when I talk sternly to him. Yeah, the two little rat dogs are good for alerting, but the muscle is in the big dog.

  25. And well well, the low frequency tremor is rising again in the background, just like a month or so ago. And this time, its the same, with only lowest freq rising without the mid or especially high freqs. And this time, Iceland happens to be directly under a big fat ridge (anticyclonic high pressure area), and the forecast is calling for continuation of calm wind and sea, so its neither wind and especially not sea waves, and neither were the last time this appeared. This is most evident at/around Vatnajokull and S/SW Iceland.
    And with weather effects minimalized, you can really start to see and appreciate the slightly elevated base level tremor at some places, especially Vatnajokull, and Badarbunga area.

    • On DYN I see the opposite, only the high frequency rising and not the low one… Since there is no wind then I think hydrothermal activity is the most logical explanation.

      • Or are you speaking about the very recent rise? In this case I think it’s neither strong enough nor long enough to make it really significant.

          • That was kinda the idea, and why I said “hydro activity”. 😉

            That red line tho, is a story of its own.

        • I have never been a fan of these plots, there is way too much noise and so many things going on that cannot be explained easily, I am sure to someone they mean something lol

          The other thing, by the time something shows on these it is obvious that something is going on

  26. And, we have an M1.1 quake emerging at 10km, in the region of the “elbow”. It might seem to be nothing unusual, but actually, that is in my view a pure MT quake. Look at the drumplot signature, where first there is slight tremor activity and than later, after the tremor amplitude increases, we get the initial break of the M1 quake, and the tremor signal gradually reduces. Not to mention this is a station not so close to the actual quake. It was also registered all the way up to Askja. The tremor is also visible on nearby stations, except on GRF where its probably damped a bit by the Grimsvotn magma chamber or by local characteristics.

    • Caught my eye, too, and I am glad that those more knowledgeable than me give it a similar interpretation. And there was a similar one, but shallower, at 10.25. I wonder whether they’re related?

        • The one at 15:57 was very strange?

          it is now listed as a M1.2 but look how far afield the signal went, I checked USGS to see if there was a large quake somewhere else but it shows on drums a quite a distance. BB is awfully rumbly today

          • This is exactly what I was talking about earlier, about low frequency non-teleseismic pulsing or spiking. Kinda like very deep quakes, but not really quakes.
            It is not teleseism, neither by signal or frequency.
            The signal did came somewhere from Vatnajokull.
            Given the amplitudes, it was somewhere between Bardar and Grimsvotn. And it was deep, because only stronger activity at depth can cause such widespread low-mid freq signal at various station and with similar intensity that far out.
            Something shifted at depth, or it some stronger glaciar activity. Because that wouldnt be listed on the quake list, because as stated by IMO, they do NOT list ice quakes or ice activity on the quake list. Ever. 🙂

            An interesting and also weird day for Vatnajokull or Bardar, I tell you. 🙂

          • I think some of this is maybe heavy melt, there is a great deal of similar noise on other drums and now the puzzle of the 15:57 burst seems to have been the quake Luis posted below which happened just before the M1.2 and the signals run into each other.

          • There were actually two quakes south of Iceland that made up this noise, there was an M4.1 at 15:54 as well as the M4.7 at 15:52, both show on the drums as well

            not on USGS, have to make sure to check EMSC next time

          • 15.38 is an odd looking one, too. IMO haven’t got it up, but there doesn’t seem to have been anything else at that time that it could be.

          • @ Down under: I’m not familiar with the word “teleseismic”. Does it mean the kind of traces left on drumplots by weather, traffic, etc?

          • Thank you, Bjarki. I book-marked that glossary recently, too… Hmm..!

    • Historically we know that Oraefajokull is a giant active and dangerous volcano, but no one would expect other volcanoes in between, in direction to Grimsvotn.

      Now I start to think about whether there could be really something else going on in between them. Because we often see small swarms in there, and geology under the ice cap is mostly unknown!

      Personally I think it even seems like a fracture zone, directly perpendicular to the direction of rifting, that´s why we see the quake alignment towards Oraefajokull. All over the Atlantic, we see these faults perpendicular to the rifting, it shouldn´t be an exception in Iceland too.

    • From the Link;

      “Geologists in New Zealand have discovered a magma chamber being born in a surprising place — not under the country’s most active volcanoes, but off to one side.

      The finding suggests that molten rock can accumulate underground in complex and unexpected patterns, but does not indicate that an eruption is imminent.”

      And, as a side note. The Taupo caldera seems to have been a decendant event to the Whakamaru Caldera. The area of the two chambers spatially overlap a bit. So having a chamber “off to one side” seems to fit the Taupo-Whakamaru relationship.

    • Uplift in this region (along the coast) seems to have been known for a long time. The paper mentions raised beaches dating back as far as 1700 yr. They have done measurement on land, but the main earthquake activity is off shore. Islands of the coast also show uplift (from the paper). So the magma chamber is mainly off the coast, and much larger than they were able to measure. But it is a long way off from becoming a volcano. We are talking thousands of years or more. Taupo seems to have gone dead as a dodo (not quite their words).

      An interesting aside: they find measurable subsidence at the location of a geothermal power plant. That suggests a way to combat sea level rise: put a geothermal plant in your threatened area (Miami, say), invert it to so rather than extracting heat from the ground it puts the heat in, and see the land rise. Don’t turn it off.

      • In what way are they discerning Taupo being “dead’, and why do they believe it’s a long way until this feature becomes a volcano?

        • Dead in the context of not detecting signs of magma movement now and (hopefully) a long time in human lifespan measures before it does wake up.
          I have no idea how they discern / model expected behaviour of the new feature. The rate of inflation has reduced over the past few years, but they don’t really have a reference to how the zone may behave based on past observation of similar events locally. They talk about risk to Tauranga (about 50km from the zone) but point out that’s at risk anyway from ashfall etc from other volcanoes in the TVZ (also Mayor Island, White Island perhaps though that’s had a history of frequent small eruptions rather than large ones). It’s also at risk from local (Kermadec Trench) tsunami – tectonic or volcanic – as well as local large-ish earthquakes.
          The intrusion rate of magma – if it continued at the highest rate they’ve observed, then it would still take many hundreds of years to accumulate volume equivalent to a Tarawera sized eruption. It’s very likely that something else pretty big will happen in the meantime.

        • They find that the entire Taupo area is deflating, consistent with cooling magma. Seismic data also shows that the area is quiet. The combination suggests nothing is imminent. As to a new volcano, they don’t make predictions. But using their numbers for magma incursion (0.01 km3 per year), and a decent chamber for a large eruption being 100 km3 (guessing 10% of the magma would erupt), suggests 10,000 years. Less if they missed a lot underneath the sea.

    • Yes, that was pointed out in one of the comments above. I had missed that one, as it only came out a day or two before our post, otherwise I would certainly have referred to it. It is a good article. Although the region is on the Yellowstone hotspot trail, the current activity there cannot be directly from it as it is now too far away. The NW-SE orientation suggests the Craters of the Moon is more directly associated to the great American rift which affects much of the west of the US.

  27. Something seems to have kicked off under Ruapehu. Semi-continuous low-level tremor started around 10pm Sat. night – and it’s not wind; it’s a beautiful day and not even slightly windy:

    • I agree – there’s almost no wind.and a similar trace is also showing on the Wahianoa drum. Light winds and clear weather forecast for the next few days, so if something happens there would be a clear view on the webcams. It’d be interesting to hear if Geonet have anything to say – there’s no comment on their Facebook page. I guess as it’s been very windy at times since they increased the alert level, similar activity could have been masked by wind noise, but it looks interesting.

      • Actually I’ll be up there tonight and tomorrow. Probably stay in Taupo or maybe in the motel at Waiouru. Not expecting anything to happen; this is an already-scheduled trip. My eldest son has a big geology project at school and we’re going to have a poke around mostly looking at ignimbrites. But I’ll take a camera just in case 🙂 – best way to keep NZ safe and guarantee nothing happens lol.

        Interesting how the tremor kicked off very suddenly. You can see it clearly on the far right of the SSAM plot:

        • Yes I think so – WRT the SSAM plot at about the 5Hz frequency. It’s not showing like that on past data displayed back to May 1 – including when the SSAM chart is displaying data from when it was very windy.
          Have a safe trip – weather forecast looks good.

        • Well I just had cause to speak to a GNS volcanologist on another matter – and they reckon it’s likely hydrothermal; this isn’t uncommon. They think the lake is heating again and this low-level tremor is caused by water moving and circulating in the lake and in the hydrothermal system under the lake.

    • 3.4 seems to be the standard size in that corner of Bardarbunga. This is the third in two weeks.

  28. FYI The next post is planned for later tomorrow. With apologies for the long time between posts: available VC man/woman power has been affected by work, illness, and apparently a misjudged parachute jump. The planned post moves us back from the US to the mini-continent of Europe.

    • Well now we all want to know more about the parachutist!

    • No need to apologize. I think we all understand that all authors have normal lives that sometimes have to be prioritized before the blog. To maintain the high quality of the posts must take an awful lot of time and I am thankful for all the effort that is put in. I have learned a lot from reading this blog, so keep up the quality and never mind the occasional silence.

      A misjudged parachute jump sounds quite serious. I hope all is under the circumstances well for the unlucky one.

  29. Fascinating article, Albert. I would have written sooner, but my family and I were on vacation (Monterey/Big Sur, San Francisco, & Las Vegas) and it put me out of the loop, thankfully, for over a week.

    I have always been fascinated by the American FarWest. North from the Orcas Islands and Cascades of Washington and Oregon; South through the Basin/Ranges into the Imperial Valley of California; East to the convergence of the Rockies and the Grand Canyon and southern rift valleys; and, West to the Big Sur and the Redwoods and Sequoias of the Coastal and Sierra Nevada Ranges of California. All geologic natural wonders.

    I read someplace a few years back that the reason that there isn’t an obvious trench at the Cascadia Subduction Zone was due to the Missoula Floods depositing (basically) all the soil from the channeled scablands into the trench via the Columbia River a few thousand years ago. Makes sense, it is buried.

    However, there are a series of N/S trending ridges on the sea floor beginning due west of Albany, OR extending north to the mouth of the Strait of Juan de Fuca; sitting right where one would expect to see a trench in a subduction zone. The northern and southern extents of the ridges are almost equidistant to the mouth of the Columbia River. Could these ridges be sediment folded by the subducting Juan de Fuca plate, Missoula sediment pinched against the continental shelf as the plate dives from under it? If so, how quickly is the plate subducting to cause a mountain range this large to form in about 10kyrs? If not, what are they? They are oriented incorrectly to be caused by turbidity current erosion – as a matter of fact, the turbidity current has cut through them at the mouths of the Columbia, Chehalis, Queets, Hoh, & Quillayute Rivers. They are not volcanic – that is to the east and west of them. The only dry-land analog I have seen in the region is a single N/S trending ridge north of Black Butte, OR and west of Camp Sherman and Three Fingered Jack. On a larger scale, they appear similar to the Basin & Range Provinces of NV, CA, and UT.

    Anyone know what this is and what geologic actions are to blame?

    • I don’t really know! But the ridges look very much like turbidity flows and that would be my guess. There are two unusual aspects here: the continental shelf is much steeper than normal (so more prone to these flows), and the original sea floor basin has been uplifted a lot – so turbidity deposits are now much closer to the surface.

      • I agree with this -one interesting aspect is the Cape Arago area
        of the south central Oregon coast- You can see the folding of
        the old seabed on the shore. I always gave me pause about the
        forces at work off the NW coast…
        I call it “that ‘ol Demon that lives under the cold water..”
        This is a good paper on that area;

  30. Yeah flood basalts are too awsome! I always trys to imagine how it was like….
    how big where the fountains….and how large where the lava rivers?
    I have been facinated by flood basalts for years

    maybe flood basalts are too huge to imagine?

  31. I always thinks of flood basalts of how it must have been like…

    take the Rahajamundry traps lava flow…a single flow unit from Deccan Traps …the Rahajamundry traps lava flow have a volume of 9000 cubic kilometers and flowed 1500 km across the indian continet! The fissure vent was in the west…

    • There’s always the time factor involved and since it’s 66 mY BP and the dating used is K/Ar with an uncertainty of several %, it could be that this flow, so massive on paper, actually took tens if not several hundreds of thousands of years. The 9.000 km^3 may work out to be no more than an average of <1 km^3 per year which is not that impressive.

  32. maybe that……..or maybe the Rahajamundry flow was like Columbia river basalts erupted at insane speeds and rates….we dont know

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