The Wandering Earth: mantle in motion

The Kola superdeep borehole

It is nice to live on the crust. It gives a degree of stability which the rest of the Earth lacks. It is not perfect: the quiet can be punctuated by earthquakes or volcanoes, and lacking those there is still the off-chance of a landslip or flood. The atmosphere may also interfere with our lives. Take Kansas (to UK readers: that is like Milton Keynes without the roundabouts (traffic circles), the people, or the city): it is amazing how much destructive weather a place without an alleged atmosphere can still have. Actually, living on the crust can be pretty precarious. But don’t complain too much. Dig down into the solid rock and below those you’ll find ever-moving currents. We are living on a thin shell above a seething ocean of rock. Do you remember those people of the previous post walking on thin ice? That is us.

The picture above shows the location of the Kola superdeep hole. Over a period of 20 years, the Russians dug down to more than 12 kilometer below the surface. It was an amazing feat. It is near the Norwegian border and there may have some concern that parts of Norway could fall in. After almost 25 years, the project ended in 1994. Since 2008 all maintenance has ended and the buildings are now in ruins. If you have seen the ruins of Chernobyl already, you may want to try this next, although I am not sure that it is possible to get permission to visit it. The Kola project penetrated only about a third of the crust before the increasing heat made any further progress impossible. The scientists complained about the rocks down there being more like plastic than like rocks. It is hard being a scientist.

The previous instalment discussed the pliability (or otherwise) of the material of the Earth’s crust. Cold rock is stiff and immovable. Hot rock, as found in the Kola drill, is more deformable and can creep. Glass stays put while honey runs. We saw how mountains grow and volcanoes sink, on the shaky foundation of the warm rock below. But now it is time to look deeper. A lot deeper.



The crust consists of two very different regions: oceanic plates and continents. They have in common is that they form the top layer of the Earth, immediately below the oceans and atmosphere; also they are the only parts of the Earth broken into pieces (called plates). But if you had found a bit of continent and a bit of oceanic plate, you would not have put them together in the same category. Oceanic crust is dense, thin (almost always around 6-7km), and mafic. Continental crust is thick, light, and felsic (rocky). Continents rise far above oceanic crust: this is because their rocks have much lower density: they float on the denser material below. The thickness of continental crust varies tremendously from place to place, ranging from 20 to 70 km. Oceanic crust, on the other hand, is dense – almost the same density as the mantle below. The density depends a bit on temperature: when it is hot it is a bit less, when cold a bit more. This is the reason that oceans are shallow above mid-oceanic ridges (where the crust is young and warm – if 2 kilometer depth can be considered shallow), but 5-6 kilometer deep where the oceanic crust is old, has cooled, become denser, and therefore lies much deeper. Don’t age oceanic crust too much, as it will begin to sink. That gets ahead of the post, though.

The crust almost everywhere, whether oceanic or continental, is cold and stiff. It acts as a tough solid. Think biscuits. If you flex a biscuit, it will break into two or more pieces. Dunk it into tea first (I have no idea why the British do this), and it now bends with the pressure. The crust is like an un-dunked biscuit, and it too has broken into pieces under stress. Each plates moves as a single , solid entity. Only where the crust is hot (say Iceland) does it become flexible enough to bend. Here, the plate boundaries become fuzzy, and bits can change allegiance and glue themselves to a different plate.

Just below the crust sits the top-most layer of the mantle. The composition here changes: the mantle is ultra-mafic, and so also differs a bit from oceanic crust. The line between the crust and mantle is called the Moho. The top-most mantle is rather cold, at least when compared to the rest of the mantle. The deeper one goes, the warmer it becomes. The bottom of the top-most mantle is defined as where the temperature is around 1600 K. The depth varies between locations: underneath the oceans it is typically at 100 km depth, while underneath continents it can be as much as 200 km. To put this into context: it would have taken the Kola project 400 years to get to this depth, at the rate which they were going!

The temperature is important because higher rocks are below this temperature and are rigid, while below this level they become deformable. The rigid top-most mantle is frozen to the crust and they move together as a single block: plates consist of crust and top-most mantle, combining regions with very different compositions. The crust and the top-most layer together are called the lithosphere.

The bottom of the lithosphere is warm enough that the rocks begin to show measurable creep. This raises the question how to measure their viscosity! The best way is to add a mountain and see how quickly it sinks. Hekla did this, but it is rare to have mountains that grow fast enough for this. The next best thing is ice. During the ice ages, ice caps grew on the continents, eventually measuring 2-3 kilometers tall and thousand of kilometers across. That is a sizable mountain, even allowing for the fact that ice weighs less than rock! The tremendous weight pushed down on the land, and it began to sink. The nice thing for geologists came afterwards. At the end of the ice age the glaciers melted very fast, much faster than even the warm lithosphere could respond. The land started to rebound at a rate set by the viscosity of the lower lithosphere. Even now, ten thousand years later, the recovery is still not complete. The Hudson Bay is an example of a large depression left by the weight of the ice, which is still recovering.

If you don’t like equations, feel free to skip the next bit. Let’s take a look immediately after the ice is gone. There is now a depression where the ice used to be. Let’s assume that this depression is completely filled with water (not unreasonable), as it is in the remnant of such a depression, the Hudson Bay. At the depth of the lower lithosphere, the pressure is equal to the weight of rocks (and water) above it. Outside the depression, the weight is that of the rocks, but inside the depression, the upper rocks are replaced by water. Water weighs less than rocks, and so there is a pressure deficit. The deficit is equal to ( ϱ – ϱw) g d where d is the depth of the water, ϱ is the density of rock, ϱw is the density of water, and g is the gravitational acceleration. The depth of the lithosphere does not come into it.

This pressure deficit gives rise to the buoyancy force: it is what makes the depression rise up. As it does so, material of the lithosphere must be flowing in to fill the gap, sucked in by the same force. It comes from beyond the depression, and so flows in over a considerable distance. But this flow suffers from the viscosity, which slows it down – rather severely because the viscosity is very high. Friction acts as a force which is pulling back. The total friction force is equal but opposite to the total buoyancy force. We know the velocity (from the speed of the rise), and the force (from the equation above), and therefore can calculate the viscosity constant which relates the velocity to the friction force. For the Hudson Bay area, it gives a value of around 1021 Pa s. Even the lower half of the lithosphere is about as stiff as glass. The flow velocity is therefore very slow, about 1 cm per year.

The value of 1021 Pa s is typical for the lower lithosphere, but values can vary a lot depending on local conditions. Values can be as high as 1025 Pa s, but much lower values are also possible if there is a local heat source. This happens for instance underneath Hekla: a normal lithosphere would have had no problem carrying its weight, but a magma chamber does not behave like a normal lithosphere. Mountains and volcanoes both tend to have lower viscosity underneath them.

Mauna Loa is a good example. This enormous mountain has depressed the local lithosphere. If you look at a map of the sea around Hawaii, you will see a trough running along the east and south side of the Big Island (which in spite of its name is a lot smaller than Australia). It is called (no prizes for guessing) the Hawaiian trough, and it is more than a kilometer below the surrounding ocean. Blame Hawaii. Sediment has filled in the trough on the other side of Hawai’i.

So if you feel the ground sink underneath your feet, and you can rule out quick sand, think lithosphere and perhaps consider the need for some weight loss to gain rebound.


Go further down and you reach the asthenosphere, the boundary layer between the lithosphere and the upper mantle. Here something else comes into play. As you continue to go further down, the temperature increases. The pressure also increases, and the higher pressure makes the melt temperature increase as well. But the temperature increases faster than the melt temperature and at the bottom of the lithosphere, the temperature becomes marginally higher than the melting temperature of the pure solid. This layer is partly melted (it is the yellow area in the figure). Go even deeper, and the temperature increase becomes much slower while the melt temperature increases further. Below 200 to 300 km everything again is solid. The whole region has a lower viscosity than the lithosphere, but the partly melted area is particularly low.

The solid lithospheric plates sit on this layer of low viscosity layer, and it acts as a lubricant. This layer allows the plates to slide. And whereas the glass-like lithosphere would only move at 1 cm/yr in response to ice ages, the asthenosphere is happy to allow faster motion. The plates manage to move at speeds as fast as 20 cm/yr. It sounds impressive – but can we put some numbers on this?

Plate power

So the plates slide at their leisurely 5-20 centimeters per year over the lubricant of the asthenosphere. The asthenosphere does not take this lying down, and tries to stop the plates with friction. The friction force depends on the friction coefficient (similar to the viscosity), the weight of the overlying plate (ouch) and the velocity (miniscule). From this you can expect that plates can go faster if they are less massive (small or thin), sit on top of some serious heat (higher temperatures reduce the viscosity), or experience a stronger pull.

The hottest areas are in the southwest Pacific, and indeed Australia is moving towards there at breakneck speed. India is a better example, though. After it left Madagascar behind, it moved across the newly named Indian Ocean, initially slow, than accelerating to 20 cm/year, and later slowing down again to 5 cm/yr (still far too fast). Why the acceleration? A suggested cause is the Deccan hot spot. India encountered it in the middle of the ocean, and it provided the heat necessary to reduce the viscosity. It also melted part of the underplating, thus reducing the weight of the subcontinental plate. The friction reduced, so India sped up. After it left the hot spot behind, friction increased and India slowed down again. People move faster with a bit of heat under their feet.

How much energy is involved in moving a plate? This may surprise you. Consider a continental or oceanic plate as a square of 2000 km on the side, with a thickness of 100 km. Let’s give it a velocity of 5 cm yr-1 and a density of 3000 kg m-3. The kinetic energy of the plate is a measly 1.5 kJ. This is similar to a car driven at 10 km h-1! Archimedes said that with a long enough lever, he could move the Earth. It turns out, he could have done it with his Landrover. India hitting Asia really was like a car crash. Of course there is one basic difference: the Earth kept pulling on India during the collision, and so the energy lost in collision was constantly being replaced. It was like a car crash where the car just wouldn’t stop.

So the plates are constantly being powered. The question is now, where is the engine?

Mantle convection

Below the asthenosphere lies more mantle. The asthenosphere ends at around 250 km deep. Below this the mantle is exclusively solid. There are two layers, the upper layer down to 670 km, and the lower mantle below that down to 2900 km where the core begins. Both consists of forms of silicates: the form changes at the 670 km boundary. Don’t underestimate these depths. The Kola project could have reached the bottom of the crust in 60 years, the mantle transition zone in 1300 years, and the bottom of the mantle in 6000 years. We are really living on a very thin shell.

The mantle consists of a variety of silicates. They are not stone: it is more like compressed sand. (Actually it is nothing like sand but ignore that.) The viscosity increases with depth, reaching around 1022 Pa s in the lower mantle.

The temperature keeps rising as you go deeper. The temperature gradient makes the mantle convective. This is the same effect you see in a pan of heating water, where you can see hexagonal cells of rising water. You can also see it in a growing thunderstorm in the atmosphere. Take a pocket of air. Heat it, and it expands. The expansion lowers the density and suddenly it is lighter than the surrounding air. It becomes buoyant and rises. As it rises, the pocket cools but so does the air around it. What happens next depends on how quickly the temperature in the atmosphere drops with height. If there is a steep temperature change, the rising pocket will continue to rise. If the gradient is shallow, it won’t.

Here is an example in the atmosphere, over the Sandia mountains in New Mexico during the summer monsoon. The convection is driven by the heating of ground by the Sun. The hot ground heats the air above it, and the temperature gradient is now large enough that it will rise – and fast. Later in the day, the ground will cool again, the temperature gradient becomes smaller and the convection stops.

There are two ways to start convection: heat the bottom or cool the top. Both happen in the mantle: heat from the core enters from below, and heat escapes at the top. The escape is mainly through the oceanic crust; the continental plates are much thicker and insulate well. This makes the top mantle warmer underneath the continents and should suppress convection there.

But it is never as simple as this. First, the continents move, and it takes a long while for the mantle to warm up. Heat transfer (‘thermal diffusion’) in the mantle is very slow and can take more than 100 million years. So the temperatures of the upper mantle relate to where the continents were some tens of millions of years ago. Second, if there are different temperatures in the upper mantle, you get sideways flow as well. The hot material at the centre of the continents will flow towards the cooler edges. That will suck up material from lower down, and so you still get an updraft started underneath the centre of large continents. But as there is no buoyancy involved, it will not go deep but instead give shallow convection.

This introduces the first big problem with mantle convection. The 670 km layer acts as an inversion layer, and it is hard for convective cells to punch through. There are two main models for mantle convection, one where the whole mantle acts in unison, and one where the upper and lower mantle convect separately. The two models are shown in the figure (reproduced from

There are more problems. The nice picture with a few cells and well-defined plumes and downdrafts appears optimistic. The problem lies in the Rayleigh number of the mantle. This number gives the ratio of the heat transfered by convective bubbles over the heat transfered by conduction. This number is around 107 for the mantle and that is very large. It means that the ‘plumes’ can form anywhere and be of any size, and it makes the convection highly turbulent. Because the convection is so efficient in transporting heat, the temperature gradient in the mantle is much less than that in the lithosphere. The convection warms the top and cools the bottom.

The whole mantel is vigorously convective, and left on its own the convection can become chaotic. Here is a simulation that begins to show the effect. Initially, the mantle convection is well behaved. But over time, it begins to resemble spaghetti.

This raises questions. Plates are quite large and their motion seems related to the convection below. If the convection is chaotic, the plates should be pulled in all directions simultaneously and therefore not move at all. Also, there are some clear mantle plumes such as the one below Hawai’i and under Reunion. These show that there are large scale convective cells which are well behaved and not chaotic. Such clear cases are actually quite rare. For Iceland we don’t know whether there is a deep source and for Yellowstone there is also still some doubt although its case is stronger. If the convection is caused by heat from below, why are there only few such strong plumes? If it is cooling of the oceanic plates, shouldn’t the updrafts be close to subduction zones where the surface is coolest?

The answer seems to be that the mantle convection is not caused by either. It is caused by those plates. As the oceanic plate cools over time, it becomes denser than the mantle below. Now the plate starts to sink: there is subduction. The subducting plate sinks, often at an angle of around 45 degrees. As it sinks it compresses and warms up but it remains colder than the mantle around it and therefore keeps sinking. The sinking pulls the rest of the plate with it. The drift of the plate is not driven by convective currents in the mantle: it is driven by the pull of the descending plate. This plate descends to a mantle with high viscosity, and therefore also pulls that along with it. The mantle begins to move.

The mantle is very unstable to convection. It would be filled with rising and descending bubbles of all sizes. But the descending plates bring order to the chaos. They induce a large scale pattern. Whether this pattern is shallow or deep depends on whether the plates penetrate the inversion layer at 670 km. There is strong evidence that some do, but plates can spend considerable time near the boundary. This suggests that much of the regular convection pattern of the mantle may be shallow. However, the two regions are not fully separated and some convection does penetrate the layer and combines the whole mantle.

So what is the engine for the plate drift? It is in the plates themselves: the driving force comes from the subducting part of the plate. (This topic is discussed in more detail in the old post The Dancing Earth.)

Mantle plumes

There are 43 recognized hotspot swells, where sufficient heat arrives at the surface to create a notable bulge. That includes Hawai’i where the bulge is visible on the sea floor, surrounding the depression caused by Mauna Loa. Such bulges may be associated with mantle plumes, but not all of these may be deep. A bulge indicates heat, but does not say where the heat comes from.

If we rank these spots according to mass flux, we get the following list. Here the mass flux is the amount of mantle material flowing up through the rising plume in km3 per year. I calculated it from the buoyancy flux. This is not the same as the magma production rate, as only a small fraction (of order 1%) of the material will melt. For instance, the mass flux for Hawaii is 12 km3 per year, but the magma production is only 0.25 km3 per year. The magma may also derive from material arriving near the surface over millions or tens of millions of years: flood basalts obtained their volume by tapping into a pre-loaded reservoir.

1. Hawaii 12 km3 per year
2. Tahiti 7.5
3. Marquesas Islands, 6.5
4. McDonald Seamount 5.9
5. Easter Island 5.4
6. Pitcairn Island 4.0
7. Louisville 3.2
7. San Felix 3.2
9. Samoa 2.6
9. Caroline Island 2.6
9. Juan Fernandez 2.6
12. Yellowstone 2.4
13. Iceland 2.3
13. Reunion 2.3

The numbers are not highly accurate as I have assumed that all plumes have the same temperature. For cooler plumes (with smaller temperature difference between the plume and the surrounding mantle) the numbers may be a bit underestimated. The amount of magma may also differ from this order, as it depends on what fraction of the rising plume melts, and magma may have build up over a longer time.

The plumes themselves are not large: even for Hawaii, the rising column is less than 100 km across. The bulbous heads of the plume are much larger: for Hawaii, the swell that is caused by the head is a 1000 km across.

Knowing the mass flux, we can calculate how much heat they deposit at the surface. It turns out, if we add up all 43 hot spots, the total is only about 6% of the full heat flux from the Earth. The remaining 94% comes out mainly through the oceanic plates, and comes to the surface through normal mantle convection. The plumes therefore account for a very small part of the mantle activity. The plumes are fast though. They may rise as much as 0.5 meters per year, compared to the typical speed of mantle flow of 5-10 cm/yr.

What is causing those plumes? They appear anchored to the core (because those hot spots keep more or less the same position, apart from some deflection, while the plates move over them). They must therefore be heated from below. But the core is liquid and therefore pretty good at distributing heat. There is also some heating inside the mantle by radioactivity, but this cannot be very much because if you heat a material throughout, it reduces or suppresses convection which is not what we see. So why do some areas at the bottom of the mantle have excess heat?

It has been suggested that the answer lies not in the core but in the plate tectonics. As oceanic plates subduct, they dive down and if they can get through the 670 km barrier, they’ll sink to the bottom and may form pyramid-shaped piles on the CMB. It is possible that such pyramids anchor the hot spots. They can be slightly warmer because they are denser, and gain some heat from compression. This model explains the fact that the hot spots appear fixed with respect to the core, and it links their life time to the Wilson cycle of around 200 million years. But it is far from proven. And many ‘hot spots’ are not linked to deep plumes, but to much shallower heat reservoirs, which may have been left by a past continental plate or an extinct plume. The spaghetti structure of the mantle is not conducive to develop many such plumes.

This comes back to the previous problem. If the convective pattern of the mantle is rather irregular, how does mantle convection drive plate tectonics? In the traditional model, the mantle current which is flowing underneath a plate pulls the plate along. That has difficulty to work, not only because the currents don’t easily develop but also because the friction along the asthenosphere is rather low – and this friction is needed to pull the plate. It turns out that these objections are correct. As discussed above, mantle convection does not cause plate tectonics. That should already be clear from the fact that the motion of plates near the well-known hot spots seems utterly unaffected by those plumes.

Instead, plate tectonics is largely driven by the oceanic plates themselves. As they cool, they subduct, as they subduct they change to a denser mineral and sink faster. The sinking plate pulls the rest of the plate with it. It acts on the lithosphere which is much stiffer than the asthenosphere – so the plate moves as a complete block. Don’t blame the mantle – blame the crust.

Putting in some numbers for a typical oceanic piece of crust, based on its over density and size, and assuming it descends to the 670 km layer, you’ll find that is exerts a force of a few times 1013 N/m. Now using the equation for the velocity, v = F/η, with a typical speed of 7 cm/yr, we find a viscosity of 1022 Pa s. This is quite a high viscosity. The asthenosphere has a much lower viscosity. The friction that slows down the plate comes from the most viscous layers that the plate encounters. This may also include mantle acting on the plate that is already descending.

How long does a subducting plate survive? It can be surprisingly long. An oceanic plate is around 7 km thick, and so the question is how long it takes mantle material to enter this, until it fully mixes into the plate. If the plate is stationary, that takes forever. Even helium, normally very mobile, would only have migrated around 50 cm since the Earth formed. But the plate is moving, and the shear at the edge speeds up the mixing. Now it takes 1-2 billion years before the plate is no longer there. The heat of the mantle enters a bit faster, but it can still take several hundred million years before it has the same temperature as the surrounding mantle. That doesn’t stop it sinking, because the oceanic crust is about 5% denser than the mantle (poor in Mg, rich in Al and Si).

The lid-osphere

What happens when a convective cell reaches the surface? It meets the lithosphere, and this is a rather tough nut to crack. The temperature drops a lot over the lithosphere so in principle it too could convect. In practice, it is far too hard for that. The mantle material below which is convecting is not a soft touch, with a viscosity of up to 1022 Pa s. It does its very best to make the mantle great again. The asthenosphere gives way to the onslaught but still acts as a buffer. The lithosphere has an even higher viscosity, though.

If the viscosity of the overlying layer is no more than 100 times higher than that of the incoming convective bubble, the convection just moves on, upward. If it is more than 3000 times higher, the surface repels any attempt of the bubble to move up, and it acts as a stagnant, immovable lid. In between, there is some flow but no convection at the surface, and the surface may bulge and move sideways. On Earth, this in-between situation applies, and the crust is mostly mobile. In many places, an incoming bubble will create a bulge, and this is indeed how we detected the presence of a rising plume. But continental crust, with its thick lithosphere, may respond reluctantly. The sluggish response makes the plume move outward, and the head become much wider than the narrow tail below.

Here are video examples of the two cases

First a mobile lid

and second a stagnant lid

In a stagnant lid, convection completely stops below the lithosphere, and the two regimes remain separated. In a mobile lid, there is some turn-over where lithosphere material descends into the mantle. That makes heat transfer to the surface much more efficient. In a mobile lid situation, the mantle is relatively cool. A stagnant lid insulates, and keeps the mantle warmer. As far as we know, Earth is the only planet in the solar system with a mobile lid. The mantle of Venus may be quite a bit warmer than ours.

It s not entirely clear why the Earth has plate tectonics. The plates are the driving force of convection, heat transfer, mountain building, etc. But the Earth could quite happily have had a stagnant lid. A major question in Earth sciences is when plate tectonics first began. I would put it quite early, because of the change in diamond composition which happened 3 billion years ago, which seems to require oceanic plates to go down and mix into the upper mantle. But others have put it more recently, or argued that plate tectonics has been intermittent.

The tip of the iceberg of mantle convection are the volcanoes. They get their energy from the mantle but the melt from the lithosphere. Without plate tectonics, there would still be volcanoes – Venus and Mars both have them. But they might be quite different from ours.

The Earth still has many mysteries, and hides many secrets. Kola has barely scratched the surface of the Earth’s exoskeleton. Underneath is darkness. Our thin shell depends on the boiling rocks below. Kola has long been abandoned and its buildings are ruins. But the wish to understand more of the world below us remains. Perhaps one day we will drill into the mantle.

Albert, June 2019

153 thoughts on “The Wandering Earth: mantle in motion

  1. My apologies for any typos or mistakes: I have not had time to proofread today! Perhaps tomorrow.

      • I think I fixed the most obvious errors now. Sorry for this but sometimes there just is no time to do a proper job. Otherwise this post would have been two weeks later and the connection between the two Wandering Earth posts would have been lost.

    • This is an absolutely brilliant piece. Actual numbers and a believable mechanism based on them. I’m not sure how much of a maverick Albert is in this field but it makes a change from handwavy arguments that just make no sense. I never could believe that the rising lava at mid ocean ridges powered continental drift, not remotely enough energy, but big cold falling slabs of oceanic crust well they did. Somehow it took decades for this view to become accepted.

      It’ll take hours to give this piece justice but the really important thing is (and has always been) the Reynolds number of the mantle and how that behaves. I presume the computer simulations reflect this (as well as you can do with turbulent flow) given information may be limited/incomplete. If so it makes much more sense of mantle plumes as being real manefestations and I can see that a hot plume would make the rock above more fluid allowing more flow, and positive feedback is what would be required to maintain such a narrow, delicate structure.

      Well done Albert!

      No time gotta go all day!!

  2. Excellent Article Albert
    If you curious how thick my own local litosphere is
    Its around 270 km I think ( Im close to the Cratonic core in North East Europe )
    In Finland and West Russia its extremely thick
    Im in East Sweden
    Not even a huge Asteorid impact woud penetrate my craton. The arera been stable since 2 billion years

  3. Significant eruption at Raikoke, Kuril Islands- ash to 43,000ft, last eruption 1924. Maybe this will be the actual VEI-4 successor to Calbuco… Too early to tell so far, but not a bad bet- both of its last two eruptions were major. Probably the intensity will have to rise a bit more, unless it lasts a while (i.e. Eyjafjallajokull style). Coincidentally, this is the first red alert in the Kurils in 10 years, almost exactly to the day since Sarychev Peak’s big day. Like all but one Kuril volcano, it is unmonitored. It is a large area with many very explosive volcanoes. It really ought to be monitored far better! I would criticise the Russian government but perhaps that is not the best idea! 😀

    • Honestly, as much as I would love better monitoring, there are no people living nearby, and it’s probably extremely cost prohibitive to monitor this.

      I just wish we had access to better info or pictures.

    • 43.000 ft should be enough to reach the stratosphere for it’s latitude. (29kft to 36kft.) But it’s gonna take a bit of work to get up on top of the Hadley cells and I don’t know how that process works. Either way, the sulfate from this event will take about 2 months to peak.

      • I think the term as coined by one of our readers, is “green tomato summer”.

        Though not on the the peninsula, it is a member of the “Bad boys of Kamchatka” gang.

      • The estimated sounding per the “new” GFS (FV3) shows the tropopause around 33,000′ feet (~ 250mb).
        So, yer right that the plume most likely reached past the tropopause.
        In the near-term, I’m wondering what the possible impacts to the cyclone that’s currently entraining the plume at lower levels might be. All Winter long, cyclones near the Bering Straight have been pumping up ridges east of the low’s, with troughing occurring over the Western U.S. on the lee side of the ridges (high pressure). Given that this current low is progged to track “up and over” the ridge in the next week, it’s possible we could see some changes made to our local weather forecasts?

        • Possibly… but any SO2 remaining in the troposphere isn’t going to do much other than make the azaleas a little bit happier. (They like acidic soils, same as super hot peppers)

        • How weird to see a Skew-T chart on a volcano blog!
          I’m always looking for the capped area of potential energy in my storm-chasing interests. (I’m in the UK. So that means sitting on the motorway in eight miles of stationary traffic on a hot, sunny stormless day…)

          • My focus is on surface or elevated duct heights. Inversion layers can really mess up radar propagation.

            Factoid. While doing training ops in the Puerto Rico OPAREA I met the only person ever to be shot with a Vulcan Phalanx round survive. (25 mm Tungsten). He was (is) an Aerographers Mate. When he was hit he was on the bridge wing of the ship he was TAD to pointing at a cloud to his division officer. The round had traveled out of the hot area (live fire zone) and traveled ballisticly over an island. Filtering his arm when it hit and kill his division officer. Guy was in the hospital forever as they put his arm back together.

        • As a resident of California, I’ve been enjoying the troughing. Summer is usually too hot.

          • I SECOND THIS. It’s also helping keep fire season in check. After the last 4 years, I’ll take it.

      • Easily high enough.

        The cloud is rapidly heading east aided by the jet stream.

        • At minimum, there will probably will be some redder than normal sunrises and sunsets in the next few days across much of Canada and areas of the US and even Europe above about 45 degrees north latitude.

    • The SO2 plume looks impressive. Currently, the heaviest concentration is wrapping into a NW Pacific cyclone which is part of a relatively progressive Pacific pattern. To the south of the plume, a rather robust jet is tracking WSW-NNE and is aimed at the NW coast of British Columbia, which could offer a means of SO2 transport towards North America.
      Will be interesting to monitor the SO2 over the next few days and see how quickly it washes out of the atmosphere.
      Below is a GOES-17 map of the SO2 plume just released by the NWS out of San Francisco. Hopefully it will post, but I forgot the special changes to the URL (TinyPic) to make it work.

        • Hearing that parts of the plume made it to 17km and that the SO2 release was really quite strong- 1.34Tg. GVP have also replied to people on Twitter stating it was a VEI-4. Was it really that big? I’m not sure either way.

  4. Ow…

    I was watching a youtube vid that mentioned that the Toba eruption (≈75kr ago) had an estimated plume height of 50 miles. Poking that info through the Mastin et al formula yeilds a mass ejection rate on the order of 902,726 cubic km per second.

    Just an estimate based on an estimate… but still quite spooky. (Note that models, no matter how good, tend to get unreliable at the extreme ends of the data sets they were built off of, and Toba with a 50 mile high plume, falls outside of the realm of data that Mastin et al built their formula from, they also specifically state that it only has an accuracy of roughly a factor of four.)

    • 50 miles is impossible! Ash columns are believed to have an upper limit of 55km, which is about 33 miles.

      • Just going by what they stated. In general, Media types go for the greatest hype. As I noted, the Mastin et al formula wasn’t sturctured for anything of that size.

  5. Albert Im curious
    Iceland that one of the very very most productive volcanic areras on the planet ( 1 km3 to 2 km3 16 years )
    How can it have souch a very low heat bouyancy flux?
    I dont understand …

    Is it the very very very thick ( 47 km ) Icelandic basalt plateau crust that blocks most of the thermal heat comming out from the Iceland Plume
    It must be that … Im curious

    • That is an interesting question to which I don’t really know the answer. The ranking I gave is from the buoyancy flux which I converted to a mass flux. It may be a bit too low of the hot spot of Iceland is a cool one. Part of the answer may be in the mid-atlantic rift: Iceland is borrowing activity from it, and the hot spot may only be adding to it. The underplating may melt more easily than in oceanic hot spots. The hot spot may have been stronger in the past. And of course, Iceland is precisely where the America and Europe were most recently connected, so this history may play a role. In general, the buoyancy flux is not particularly well correlated to current magmatic activity.

    • Its probably the crust thickness. If you look at hawaii the islands pretty much counter any rise that the plume gives and actually the ocean around the big island is deeper than the abyssal plain further out. Iceland is way bigger than hawaii, and also more importantly iceland is bigger than the plume head (unlike hawaii) so the plume pretty much has to push up a whole small continent, which isnt likely when it can go through the rift instead. Plumes have to be really huge to push up continents, and also the continent has to be really huge too to stop the plume diverting around it – africa.

      • Dunno the direct effect. But I think there is a pretty good possibility that Iceland is a stacked plate. A gazillion years ago, there was a subduction zone in this area and a plate shard may underly the island, yielding the ultra thick crust there.

        And yes, “gazillion” is not a real number. 😀

      • Everyone says that Iceland plume is supercold ( Carl says that too )
        But under vatnajökull its around 1495 C to 1520 C ( with 1510 C generaly accepted among geologists ). Iceland is a very hot plume ( almost as hot as Hawaii even, if H is hotter still )
        And Iceland is in many recent studies I can find core boundary.

        I loves Iceland! The combination of Ridge and Hotspot and High latitude have formed a landscape that dont exist anywhere else.
        Icelands dark, gloomy mossy craggy volcanic landscapes with these heavy skies is a fanatasy addicts dream. Iceland haves a special Tolkien feel.
        Im going to move to Iceland pretty soon and Im excited.

        Grimsvötn is also getting very intresting now as its getting more and more seismicaly active on shallow levels. Its quakes almost daily now in Grimsvötn
        Coud be the upper magma chamber thats expanding and stresses the bedrock around it
        Grimsvötn generaly lacks deep quakes as its hot and ductile system.
        Coud be an eruption in 2021

        • This is an excellent article Albert made.
          The astenopshere is pretty much todays version of a magma ocean layer.
          But Earth have cooled since archean and astenopshere today is more like mushy solid thats partialy melted. Mushy layer in the solid mantle.

          The viscosity of todays astenopshere is probaly similar to the promixial type Aa flow core. The massive solid plastic core of large Aa flows.
          The astenopshere today is not solid hard and defentivly not molten
          A hard but ductile mush it is today.

          In archean the astenopshere was much much hotter, It was certainly a molten magma ocean layer
          And in early hadean the whole planet was molten

          • I meant astenopshere viscisty is similar to distal type Aa flow core
            Not close vent Aa
            My Dyslexia is so bad that I can hardly write anymore

      • Also the extremely strongly Tholeitic Basalt compostions of Iceland rocks special from Vatnajökull and the Dead Zone is a good sign mantle partial melting is very very vigorous under Iceland. The subsurface crust ( below 45 km ) from Katla to north Beyond Krafla is probaly nearly completely molten ( deep ridge melt lens thats boosted enromously by the decompressing Iceland Plume head )

  6. It has been a ongoing big swarm in new zealand. Some 6 and a pile of 5meg. Wite island is coverd on the map in eq. Can this be a eruption? And is this a vent of tapo?

    • They are mostly aftershocks of the M7 a week ago. Others are just part of the normal behaviour: this particular fault is quite earthquake prone.

      • Kermadecs are a long way from mainland NZ. The M7.2 was quite widely felt on the E coast of NZ, but would have been only a long period distant rolling motion. It’s normal to get big quakes in the region. A megathrust is possible, in which case NZ should have about 45 minutes warning time to evacuate the closest coastlines.
        That quake was too small to generate much of a tsunami – only a few inches was recorded, but there is paleotsunami evidence of massive events in the past, timescale over hundreds of year intervals – frequent in geological timescale, so a serious risk.
        The quake activity at White Island at the moment is tectonic. Volcanic activity there is more or less constant, low level, and although it’s part of the Taupo volcanic zone, that’s not a volcano to be particularly worried about – relative to other threats ranging from merely disruptive every few decades to locally catastrophic and globally significant every few hundred years or so. Or the really big ones, at thousands of year intervals.

    • Not a vent of Taupo, though all of the systems get their melt from the 110 km contour of the subducted plate… with a bit of decompression melt from the still forming back arc basin.

  7. Lovely, multi-layered report. IMHO, the growing understanding of those vast, surely-ancient, subduction generated core/mantle ‘piles’ may yet revolutionise our model of the Earth’s ‘deep history’…

    I was in my mid-teens when ‘Plate Tectonics’ broke through. Magnetic Stripes Rule !!! Our college’s Geography teachers went out in two groups and got drunk. The ‘Old Gang’ held a wake for their ‘traditional’ synclines and anti-clines. The ‘Young Guys’ celebrated PT’s long-debated but unproven hypothesis becoming the New Paradigm (TM)…

    { IIRC, the Physics guys did much the same when Quarks / Partons showed up… }

    Per the biscuits. IIRC, ‘Urban Legend’ holds the tradition stems from sail-era ‘Royal Navy’, whose long-life ships’ biscuits’ consistency rivalled ‘engineering brick’, yet were beset by mite etc infestation. So, you’d briskly tap your biscuit on the table, prompting occupants to flee, then you’d warily dunk the biscuit in fluid until ingestible.

    Related interpretation is softening ‘hard’ biscuits was essential due to poor nutrition and poorer dental hygiene which, ashore, became, ‘For Every Child, A Tooth’…

  8. I finally reached the end of this article and thank you, it’s incredibly interesting! (Had to take a break due to a night’s sleep…)

    May I demonstrate my level of stupidity by asking a couple of questions? Since all continental surface lands (countries and islands) originally came from ‘the heart’ of the planet, why are they lighter?

    I ask this because 99.99% of the upper crust is rigid, dry, cracked and in a mess due to all the external geological factors that have shaped it as it bobbed around on top of the mafic ocean beds. Is it that re-shaping that has “aerated” the upper crust, making it lighter? And I assume volcanic activity exudes the lighter felsic stuff generally, also adding lighter stuff in the top planetary “Victoria Sponge”?

    Another dumb question if I might: since the plates are cooling and pulling themselves down, are the spreading zones / ridges pulling up deeper Asthenosphere materials to fill the gap in the parting? Or is pressure from below pushing the fresh material into place?

    I suppose I could Google all this, but it would be nice to hear it from the experts! Thank you.

    Convection in thunderstorms – now that’s where my strengths lie!

    • The continents have grown over time. Their material came from melting of oceanic plates, where the melt separates lighter and heavier minerals. The lighter ones rose to the top. This is the same effect happening in in subduction volcanoes in the current age. The new volcanoes built a lighter layer on top of the neighbouring plate. When that plate began subducting, 100 million years later, the top layer was too light to go down. It was scraped off by the younger plate next to, and over the Wilson cycles this build larger areas of continental crust. Sometimes too much material is scraped and you get some oceanic crust on land as well. This has happened in parts of Cyprus and in Oman, and you can recognize these as dark areas where little will grow (oceanic plates are somewhat poisonous to life).

      You are right abut the rifts. The pulled plate breaks apart, and this allows the warm mantle material to rise up. The rising is mostly a passive process, filling in a break in the plate. The breaks can quite easily move, where the rift jumps to another location 100’s of kilometers away. Of course, if there is a heat source this can convince the plate to break at that location. You see that i Iceland where the rift is following the hot spot, causing a great bend in the mid-atlantic rift.

      • Excellent question with an as excellent answer. I asked myself that question. The separation in lighter and heavier minerals seems so obvious.

  9. A smidge OT. A cluster of 9 quakes (including 3 over Mag 5) happened early this morning on the Juan de Fuca/NA/Pacific jagged junction. Is there a suspected seamount out there? Or is that much closer to shore? The quakes were all probably more than 300 miles W of the Oregon coast. Typically, they’ll give a distance west of Bandon, OR if they’re closer.

    An additional 5.6 40 miles S of Eureka in the last 2 hours rattled nerves here in CA. Interesting times in Cascadia and San Andreas land.

    • The quake cluster NW of Cape Mendocino was due to “typical” right lateral strike slippage near the southern most extension of the Cascadia Subduction Zone….. which terminates at the Mendocino Triple Junction. This area is very active…one of the most active areas for quakes in the world.
      While unlikely, it’s remotely possible this cluster may have helped trigger the 5.6 near Petrolia given that all the quakes had shallow focii and showed similar transform fault movement despite being on different fault planes.
      Also, note that the Petrolia quake was strike-slip…a bit of an anomaly. Usually this localized area where the San Andreas bends sharply left features more oblique and reverse faulting activity instead of the more typical strike slip movements on the rest of the fault… so the strike slip movement is worthy of a little extra note. As for anything “major” in the near-future, it’s very unlikely since this exact some area was thoroughly stress-relieved in 1992 from a mag 7.2, plus there have been several other 7.0+ events within 150 miles since then.
      The caveat to this data though, is that the northern tip of the San Andreas in northern California has been dead-quiet (locked and still loading) since the 1906 Great Earthquake that ruptured the San Andreas from Cape Mendocino down to San Juan Bautista. While a little/teeny-bit of stress is being relieved by the nearby Macaama fault east of the San Andreas, overall the area immediately south of Petrolia’s 1992 quake’s stress shadow down to around Santa Rosa (about 150 miles long) has been locked up tight as a drum for well over 100yrs, so there is a significant amount of stored energy available should it catastrophically break loose…perhaps as high as mag 7.5?
      While everyone focuses on the next “Big One”, the 7’s that are often precursors to the REALLY big 8.0+ events are just as capable of similar intensity and shaking, just that the shaking doesn’t last as long, nor propagate as far along the fault.

      • A rather curious pre-event period prior to the 5.6 Petrolia quake showed up on several seismo’s, yet the nearest station in Petrolia didn’t show hardly any activity prior to the shock. The TULE station in nearby Siskiyou County on the other hand, showed activity which looks to quite similar to deep-harmonic tremor (which is common in NorCal all the way to Washington). Note that the tremor abruptly stops about 4 hrs before the main shock, and has not returned since then.
        Most likely there is something else going on to explain the drumplot(s), but just in case, will continue to monitor for any more anomalies.

      • A study done by the Oregon State University Geology dept. found that the southern part of the Cascadia fault is capable of 8+ quakes every 250 years.
        It has been roughly 310 years since the last one. these swarms make me nervous. We have friends and family on the south coast of Oregon, Northern California…
        BTW when We lived there wife had me bolt china cabinets and bookshelves to the wall..
        I went out this monring and washed ,dried and hugged my little basalt column this morning,-just kidding- thankful I put three mountain ranges between me and the south coast.

        • Correct. As I understand it, the CSZ is broken into three segments, each capable of a major quake independent of the mega-thrust 9.0+ that is possible if the entire fault were to rupture….and that the southern section has the shortest repose period of the three. While here in Redding I’m over 150 miles inland, the shaking from a southern CSZ event would still be a major event (according to USGS estimates), so even here I’m quake prepared.

          • Was trying to mine my library, but couldn’t find a paper I’d read that speculated that the 1906 earthquake may have lowered the stress field near the southern extension of the CSZ, which in turn may help explain the longer than usual seismic gap.
            But as I mentioned, it’s all speculation IMHO….especially since we haven’t really seen any appreciable quakes on the CSZ that might indicate the fault is getting closer to failure.

          • The stress release idea is plausible… but remember that the Mendocino fracture zone would be affected as well. You should look for quakes along it as well. There have been a few sizable events in the mid section of the gorda micro plate over the years. Generally this is attributed to the proximity of the Mendocino triple junction. By their very nature triple junctions are seismically noisy.

        • Gosh, guys. That was a superb and thorough response that I definitely didn’t expect. I’m in the SF Bay Area and missed the 6.5 near Napa 4 years ago. That was on an extension of the Hayward Fault, but some suspect it released SOME energy in the area. My MIL lives on the C. Oregon coast, so I feel the squishyness regarding living within spitting distance of a fault that hasn’t ruptured in awhile.

          • I think we all feel the squishyness of those unfortunate enough to live within spitting distance of active geology – with a hint of envy if we don’t

    • “Suspected” seamount? Well, Cobb is in that general area… and Axial isn’t that far away. Axial had a full on flood basalt event not that long ago. Not a lot of people noticed it other than those that had instrumentation there.

  10. A star at Mauna Loa. At least it would have been a star had Mauna Loa been in Iceland. Hawai’i only does stars on Mauna Kea.

  11. Good evening, excuse me the out of theme, but in the previous article,, there was an interesting debate with Carl about the Tambora’s shape before 1815. He stated that it had one cone with one crater, so also official volcanology, but I found the original report of the Swiss botanist Zollinger in 1855, the first scientist that climbed the mountain in 1847, here:

    For me is very important because the Wiki page of Tambora in Italian is writed by Me, and I dedicated to Tambora’s shape before 1815 a paragraph.

    I don’t know the German, so by automatic traduction I don’t know if the Tambora’s two peaks was an assumption of Zollinger or a ocular deposition of Bima’s inhabitants. if someone knows the German, here the text (page 11): “Der Berg Tambora war vor dem Jahr 1815 ein Kegelberg und zwar offenbar der höchste des bekannten Theiles des indischen Archipels, wie ich gleich nachweisen werde. Er war von jeher sehr arm an Wasser, gewährte den Bächen und Flüssen nahezu keine Zuflüsse und war daher auch wenig angebaut. Höher hinauf bedeckten Waldungen (vermuthlich von Casuarinen) seine Abhänge. Er vertheilte sich in zwei Spitzen und zwar in eine westliche und eine östliche, die auf grosse Entfernung sichtbar waren. So sagten mir alte Bürger von Bima, dass man dieselben, wenn man von Batavia her kam, ebenso schnell erblickte als den Pik von Lombok, obgleich der letztere in dieser Richtung viel näher liegt. Niemand wusste , dass der Tambora ein Vulkan war, da er seit undenklichen Zeiten nie ein Zeichen innerer Thätigkoit , also noch weniger von äusserer gezeigt hatte , weder Asche noch Lava ausgeworfen und auch durch Geräusch nicht verrathen , dass er ein Herd unterirdischen Feuers sei. Die Basis des Berges von O. nach W. hat eine Länge von 22 geographischen Minuten. Da nun die gegenwärtige Höhe des Berges noch 8786 rhein. Fuss beträgt, muss er früher wenigstens 13,748 Fuss hoch gewesen sein. Es kann aber die Höhe sogar über 14.000 Fuss und mehr betragen haben, während der Pik von Lombok (der Rindjani) gegenwärtig 11,906 Fuss hoch ist. Wenn man die frühere Höhe des Tambora berechnen will, muss man nicht aus dem Auge verlieren , dass er zwei Gipfel hatte , sonst würde man für einen einzigen die ausserordentliche Höhe von 16,000 Fuss erhalten. Meine Schätzung stimmt überein mit derjenigen der ältesten Bürger von Bima und anderer alten Leute des Landes, die behaupten, dass der Berg mehr als einen Drittheil von seiner Höhe verloren habe.”

    In page 9 were two peaks his assunption by osservation, drawing even two craters (?): “Sehr wahrscheinlich hat der Berg zwei ähnliche Krater, obschon ich nur einen erblickte. Ich schliesse dies erstens daraus , dass der Berg früher zwei getrennte Gipfel hatte , deren Ueberbleibsel noch jetzt von N. und S. her zu unterscheiden sind, durch einen deutlichen Bergsattel unter sich vereinigt; zweitens weil der östliche Krater lange nicht den Umfang hat, um den ganzen Gipfel des Berges einzu nehmen. Ich habe darum auf meiner Karte zwei Krater angegebe”.

    Excuse me for verbosity

    • Hey Alessandro,
      I am Dutch, speaking German, so will give it a try… If someone has an addition, please do!
      I think these two passages are most important.

      “Der Berg Tambora war vor dem Jahr 1815 ein Kegelberg und zwar offenbar der höchste des bekannten Theiles des indischen Archipels, wie ich gleich nachweisen werde.”
      Translation. The mountian Tambora was, before 1815, a cone shaped mountain and apparantly the highest in the known part of the Indian (Indonesian) Archipelago what I will prove underneath.

      “Er vertheilte sich in zwei Spitzen und zwar in eine westliche und eine östliche, die auf grosse Entfernung sichtbar waren. So sagten mir alte Bürger von Birma, dass man dieselben, wenn man von Batavia her kam, ebenso schnell erblickte als den Pik von Lombok, obgleich der letztere in dieser Richtung viel näher liegt.”
      Translation. He (Tambora) did divide himself in two peaks, so a western and an eastern, they were visible from far away. Old inhabitants from Birma told me, that the same (peaks), travelling from the direction of Batavia, could be recognized as easy as the Pik (peaks?) from Lombok. Even when the the Pik were at much less distance.

      To your question about the Birmian inhabitants, the writer mentions the inhabitants saw “dieselben” refering to Tambora, which means “the same”. And “dieselben” is a plural reference (dieselbe: singular – dieselben: plural), so they must have seen two peaks.

    • “Sehr wahrscheinlich hat der Berg zwei ähnliche Krater, obschon ich nur einen erblickte. Ich schliesse dies erstens daraus , dass der Berg früher zwei getrennte Gipfel hatte , deren Ueberbleibsel noch jetzt von N. und S. her zu unterscheiden sind, durch einen deutlichen Bergsattel unter sich vereinigt; zweitens weil der östliche Krater lange nicht den Umfang hat, um den ganzen Gipfel des Berges einzu nehmen. Ich habe darum auf meiner Karte zwei Krater angegebe”.

      Transl.: The mountain had very likely two comparable craters, although I have seen one. I conclude this because 1. the mountain did have two divided tops, of which the remains from the n(orth-) and s(outhside) are still recognizable, (formerly) connected by an obvious mountainpass. And 2. because the eastern crater by far hasn’t the size to contain the whole mountaintop. That is why I did indicated two craters on my map.”

      • Thank you so much, great Rob! So, the Tambora’s two peaks are an ocular deposition of Bima’s men. This is an incontrovertible historical deposition, better than a geological survey, which is supposition. Carl said in the previous article that the second peak likely was a great and elevated scoria cone because one vent of Tambora, and so one crater.

        • It’s been sdaid that pre-1815 Tambora was tall enough to be a useful havigation aid for ships in the area.A twin-peaked Tambora would be even more useful in that regard, since the degree of apparent separation of the two summits would help pinpoint the vessel’s location relative to Sumbawa

          • Carl sustained one cone and one crater for Tambora pre 1815. He said that was observed one crater and cone stated that exists one single vent, conseguently one single cone/crater. So, the eventual second peak was a scoria cone, not a second crater. Tambora, for Carl, wasn’t a double cone.

  12. Double Whamy at Bardarbunga.

    24.06.2019 13:22:35 64.676 -17.464 2.7 km 2.3 99.0 5.0 km NE of Bárðarbunga
    24.06.2019 13:19:54 64.646 -17.446 8.1 km 1.2 69.65 3.9 km E of Bárðarbunga
    24.06.2019 13:18:14 64.664 -17.406 2.2 km 3.4 99.0 6.4 km ENE of Bárðarbunga
    24.06.2019 13:09:07 64.663 -17.585 2.4 km 3.3 99.0 3.7 km NW of Bárðarbunga

    • Tripple whammy.
      Averaging 2.4km deep.
      Spattering of other mag 2 quakes.
      Any harmonic tremor?

      • M34.1 eh? And I thought the black skies, torrential rain, thunder/lightning and vibration was just the UK summer.

        • Wife was visting a cousin’s place in Northumnerland years ago,
          it was jJUly windy rainy with spots of sun-neighbor came by and said”Nice day !” he meant it.. Oregon coast isn’t any better in jJuly.

        • I was expecting something closer to an M5 to happen, but M34.1 – that’s a bit over the top.

          This little swarm of stars is not powerful enough to bring the CSM graph back up. There might be more to come, lurking around the corner.

        • Magnitude 34 quake is probably so big that not even perfectly colliding the earth with an antimatter earth would be a big enough release of energy.

          A magnitude 34 quake would be 10^13 times as powerful as a magnitude 10 quake (I think), and a magnitude 10 quake is about 12^24 j. That is about 8×10^38 j for magnitude 34 quake. Its a lot bigger than even the biggest magnetar quake we have seen.
          Supernovas can be 10^44 j, so a fair bit bigger, but supernovas also vary a lot too.

          All of them would destroy the earth and fling all its atoms away at a significant fraction of the speed of light though so…


    • I checked the locations a bit more closely, and two of the stars, including the M4.1, are outside of the usual action. There are some older events at about the same radius from the caldera. I read somewhere that if a ring fault is reversed, you would expect to also see cone sheet formation. Speculation: Could this be what we are looking at here? The quakes do have quite large low frequency components. If the answer is yes, I assume there could be a potential for small flank eruptions if it were to reach the surface at some point in the future.

      • That 4.1 is really far out! The others could be ring fault related (there’s a slight inaccuracy in the plotting). The beach balls would be interesting to look at.

        • Agreed!

          I would also like to point out that the one to the west is a bit outside of the usual action. Could still be the ring fault, but if you plot historical quakes you will find that most of the dots on the same longitude consist of the swarm of M3+ quakes in the sequence leading up to the Gjálp eruption, others are a bit further in. Doesn’t have to mean anything, but I think that anything that breaks the usual pattern is interesting.

          Blue dots are all historical M3 quakes and larger. Red plus signs are quakes in the sequence leading up to Gjálp. Green circles are the ones from yesterday.

          • Very interesting pickup Tomas

            Here is another view the quakes for the year leading up to Gjalp (marked in red)

        • Looks like the M4.1 has been relocated to the southern rim:

          24.06.2019 13:55:58 64.627 -17.505 9.8 km 4.1 99.0 1.9 km SE of Bárðarbunga

          • Close to the Gjálp swarm. More or less at the western end of the concentration of quakes making up the southern rim. You have the coordinate axes in the plot.

          • Dancing star… north rim now.

            24.06.2019 13:55:57 64.668 -17.393 4.7 km 4.1 99.0 7.1 km ENE of Bárðarbunga

          • Looking at this plot it seems the swarm has been revised again:


            It looks like two quakes over M4 now, with the largest being around M4.5. Unfortunately we can’t see the locations because they have fallen off the 48h list and the weekly lists have not been updated yet.

          • Weekly list is now updated. Here are the three stars:

            Nr Dags. Timi Breidd Lengd Dypi M ML
            33 20190624 130907.626 64.66306 -17.58523 2.411 4.55 3.50
            36 20190624 131814.556 64.66351 -17.40564 2.172 3.40 2.92
            47 20190624 135557.769 64.66844 -17.39341 4.717 4.28 3.49

            The largest one was also the first one. The epicenter was at the northwestern part of the ring fault and measured M4.55. The last one was M4.28 located on the northern part of the ring fault where the majority of the larger quakes start. In the end this looks like normal ring fault action with the small surprise of a rare western epicenter. This swarm was a good reminder that quakes in the list are preliminary, even if ranked as quality 99.0.

  13. Monday
    24.06.2019 14:03:06 64.662 -17.366 1.1 km 2.2 90.09 8.1 km ENE of Bárðarbunga
    24.06.2019 13:55:57 64.707 -17.403 2.2 km 4.1 99.0 9.5 km NE of Bárðarbunga

  14. Albert, this was thoroughly entertaining. Thank you very much.
    I took one look at the Mobile Lid/Stagnant Lid videos before playing them and thought someone had been filming heated chocolate in their blender! Now I’m hungry.

    Take care, have fun.

  15. Since we’ve touched on the tectonics surrounding the Mendocino Triple Junction, as well as past discussions on the now-defunct Farallon Plate (thanks Geo-Lurking for much of the input), I finally got around to digging up this really cool video depicting the evolution of Northwest North America tectonics dating from 40Ma as well as how the Gorda, Juan de Fuca and Explorer plates came to be.

    Also, here is the parent article for further reading. Quite informative.

    • Really cool! Thank you for sharing. Moving from the Midwest to the West Coast has moved my scientific interests from meteorology to geology/volcanology/tectonics. I still watch for the big severe storm complexes and am fascinated by microclimates, though. Weather is decidedly more “boring” here.

      • Just remember that there is a LOT of Serpentinite on the west coast. One byproduct of this is that abestos occurs naturally there.

    • That camera is going to get blown to smithereens one day fairly soon if it’s as close as it looks.

    • Yes..finally a video of those obscure blasts it’s been having for weeks now. Looks like the vent is still under sea level..but not by much. That poor camera won’t last long I guess.

  16. BUAHAH!

    A program on the SciChannel just stated Campi’s 40kyr eruption size in gallons of rock.

    “Erupted over a trillion gallons of rock…”

    • It’s actually a decent series. “Secrets of the Underground” It just struck me as quite funny since I had just used a non existent number in a comment above. (Gazillion)

      The host did a dive in Napoli bay and found numerous hot water seeps. I didn’t see any pillow magma, but the hot water seeps are alarming enough.

    • Here’s one gallon of rock. Eh…, in rock. An empty gallon in fake rock. Whatever.

      • Lots of those fake rocks in Defuniak Springs. They use them to hide the sprinkler controls for the median on hwy 331 that heads up into town. They stick out like a sore thumb and look nothing like native NW Florida rock, which is usually limonite if you can find it in all the $#@$ing sand.

        • Sprinkling the highway median! 🤔😯
          For colorful happy travels I guess?

        • Yeah, Defuniak Springs has a tourist bent they are clinging to so they try to keep it pretty in and around town. Several historic buildings in the old part of town. Years ago, it used to be a destination stop on the rail way through there. Lake Defuniak is almost perfectly circular due to it being in an old sinkhole.

      • Wouldn’t that be hectares to the 3/2? Unless you mean to be measuring a six-dimensional hypervolume …

        • right. hectare is a two-dimensional unit.
          I was thinking add a dimension so it would be the difference between x2 and x3

          must a hectare have equal-length sides?

  17. What a great article Albert!

    Two off topic geophysical remarks:

    First a dramatic heatwave is about to hit continental Europe, with temperatures of 45C predicted to blast the record of 41C in France! Whilst India is danferously running out of water.
    It’s a preview of a world heated by 410ppm CO2.

    Second, we are about to enter a close encounter with the Taurus swarm, nearest since 1975. This is the swarm that caused Tunguska. Interestingly a small asteroid atmosphere blast was captured over Puerto Rico yesterday I think. So changes of an impact are higher in days ahead.

    Good days to be sheltered indoors! Lol

    GL Edit: Especially in Colorado. Reportedly the snow-pack is at 761% above average.


      SMALL ASTEROID EXPLODES NEAR PUERTO RICO–UPDATED: On June 22nd at 21:25 UT, a small asteroid entered Earth’s atmosphere and exploded in broad daylight south of Puerto Rico. Airwaves recorded by the Comprehensive Nuclear Test Ban Treaty Organization’s infrasound station in Bermuda pegged the blast energy between 3 and 5 kilotons of TNT -a fraction of a WW II atomic bomb. The explosion was clearly visible in images from NOAA’s GOES-16 weather satellite:

      “Based on a preliminary orbit for the fireball, it does not appear to be part of the Taurid swarm,” says Paul Weigert of the University of Western Ontario. “Its orbit is typical of near-Earth asteroids which have escaped from the asteroid belt.”

      On Jun. 25, 2019, the network reported 40 fireballs.
      (40 sporadics)

      • “Airwaves recorded by the Comprehensive Nuclear Test Ban Treaty Organization’s infrasound station in Bermuda pegged the blast energy between 3 and 5 kilotons of TNT – a fraction of a WW II atomic bomb.”

        Literally true that 3-5 kilotons is “a fraction” of 15 or 21 kilotons, but that’s still a very large ka-boom. The words “A fraction of” used in that way has a connotation of a “tiny” fraction of, when it was quite a large slice of pie – not merely a sliver.

    • This one seems to be a Beta Taurid though.

      Queensland sky lit up by plummeting meteor

      “I got the bottom two-thirds of the meteor in the picture … it was the right place, right time.”

      Thousands of south-east Queenslanders saw or heard the meteor, which struck just after 10pm.

      People on social media reported seeing the flash, or feeling their homes rumble or shake from its impact, particularly north and west of Brisbane.

      The meteor is likely due to the “Taurid Swarm”, a cloud of debris left over from a massive comet that is thought to have been responsible for cataclysmic collisions in the past, such as the notorious Tunguska event in Russia.

      We are now passing closer to the centre of the swarm than we have since 1975.

      More info The 2019 Taurid resonant swarm: prospects for ground detection of small NEOs including a link to an orbit intersection animation.

    • Seems it was spotted on the way in from Mauna Loa!

      Mauna Loa Astronomy Team Successfully Locates Incoming Asteroid

      For the first time, astronomers at the University of Hawaiʻi have demonstrated that the UH ATLAS (Asteroid Terrestrial-impact Last Alert System) and Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) survey telescopes can provide sufficient warning to move people away from the impact site of an incoming asteroid.

      The breakthrough announcement was made in a UH press release on June 25, 2019.

      The telescopes detected a small asteroid prior to its entering the Earth’s atmosphere near Puerto Rico on the morning of June 22, 2019.

      The 4-meter diameter asteroid—2019 MO—which is about the size of a car, was observed four times in a span of 30 minutes by the ATLAS facility on Mauna Loa on Hawaiʻi Island, at around midnight Hawaiʻi time on the morning of Saturday, June 22.

  18. Now Ulawun is joining in- 60,000ft this time. Could this be two VEI-4s in 5 days? Looks like it; this is very similar to its 2000 eruption which was also a VEI-4.

    • Yeah that was me. I’ve updated it now. The wait for a successor to Calbuco is 100% over now!

      • 19 km plume being sustained for longer than 10 minutes, that is for sure a VEI 4, and a big one too, calbuco was ‘only’ 13 km tall plume, this is 50% taller.
        It also looks like if it doesn’t stop soon we could be going into VEI 5 territory.

        • “for sure a VEI 4”

          … only if it can hold it for 727 minutes. That’s a 6600.4 m³/s mass ejection rate (DRE). 10 minutes of it only gets you to 396021 m³. (VEI-2) Two days of it (sustained) would be a solid 5.

          Mastin et al for those playing the home game. 😀

          • I think the eruption rate would be rather more than that, ive seen values for similar eruptions that are over twice that rate, that would require only 314 minutes, about 6 hours, the eruption lasted well over 6 hours. This eruption also was more than just the plume there have been reports of several apparently significant lava flows approaching a highway in the area, there is also a picture of the eruption before the main event, it was a massive lava fountain about 400 meters tall, a dull red during the day which is similar to etnas lava fountains.

            Uluwun seems to be like the west pacific counterpart to fuego, being that it is a frequently active volcano that is very steep and tall, and potentially very dangerous, and is also strangely violent and explosive for a nearly completely basaltic volcano.

            This recent eruption is also a perfect example of why I think the hawaiian-plinian eruption line needs to be based around other factors than just magma composition, if anything gas content and then temperature above composition. Uluwun is only slightly less mafic than kilauea if at all, but yet this has still happened, twice now, and also at many other basalt volcanoes in the last 1000 years including hawaii, so things need to be revised a bit…

          • Uluwun Is much colder basalt than Kilauea and that makes it more viscous ( its similar in temperature to Etna )
            This increase viscosity and violence when very gas rich

            But Kilauea and Bardarbunga does the same IF their superhot – fluid magmas are very unsualy gas rich

          • Calbuco reached VEI-4 after ~75 minutes at 53,500ft above the crater (it erupted 0.12km3 in 90 minutes- the first phase of the eruption). Ulawun yesterday erupted for 120 minutes at 55,500ft above the crater. Definite low VEI-4, as was its 2000 eruption.

      • This is what it would look like from rabaul, proper plinian eruption in every sense of the word…

  19. Two instances of tremor on the big island. 04:55 – 05:20 June 26th utc and 15:18 – 15:38 June 26th

    I do not see any obvious quakes associated with the 05:00 tremor, maybe a different source rather than the deep area? If you look at HUAD instrument it looks the strongest there.

    2019-06-26 15:29:36 1.8 27.1
    2019-06-26 15:17:59 2.3 45.9

    They also have a new base map (I have not seen it yet) with some of the old vents and craters labeled, open street map is the description.


    • Larger tremor event beginning about 17:23 UTC

      2.4 13km SSE of Pahala, Hawaii 2019-06-26 17:29:55 (UTC) 41.8 km
      2.2 12km SSW of Pahala, Hawaii 2019-06-26 17:22:40 (UTC) 45.2 km

      • A mag 3 (brittle earthquake).

        2019-06-27 00:03:17 3 10.8 km
        2019-06-26 22:46:42 2 32.3 km

        During Pahala swarms the tremor events seem to be located to the south and deeper than the main swarm of brittle earthquakes. I guess the best explanation could be that these swarms are due to batches of magma rising into Pahala. It seems to be cyclical or at least it has been so since the end of Leilani, but not periodic. Other swarms lasted a few days, if I recall right, so probably this one is still not over.

  20. Curious doubleheader from New Zealand.
    1. White Island SO2 emissions jump 300% after seismic swarm. No other indications yet.
    2. Large boiling mud pit opens in apartment courtyard in Rotorua. There goes the neighborhood…

    It’s been a year for volcanic features appearing in people’s yards. And the tourist business around White Island is probably down for a while. That much SO2 is to be avoided.

    • Yeah, Rotorua is worrisome. Ya see, it is one of the (several) giant calderas of North Island. Many of which overlap each other. Taupo, the most well known of them, likely got it’s magmatic feed from what was left over of the Whakamaru caldera, much like Sakurajima feeds off of Aira caldera, though Sakurajima is still just a ring-fault structure.

      The big thing to notice here are the “welded ignimbrites.” Those formed when the eruptive column for the associated caldera could no longer support it’s own mass and the column collapsed to the ground in a high speed pyroclastic surge of superheated pulverized rock. As soon as it came to a rest, it sintered into place, becoming a solid rock mass. Basicaly, no place there is safe if one of those goes full-bore. No, I’m not advising anybody to do anything. Your local government geological organization gives the best advice there. They get paid to study and watch these critters. (GeoNet)

      • That diagram looks like a hot spot was going one way for several million years, bounced off Tongariro, and headed in the direction of White Island. Looking at the ages of the caldera eruptions in sequence.

        Are there large volcanoes SE of Whakamaru? If not, was it a change in plate movement that caused a redirection?

        • Everyone here knows iceland is a rift that has overlapped a big mantle plume, well TVZ is a rift that has overlapped a subduction zone… Total magma generation of the whole thing is probably close to if not exceeding 0.2 km3 per year of very hot basalt magma (over 1300 C) and unlike most other places this is mostly going into melting the granitic crust to make a lot of rhyolite, enough to make this a silicic LIP. Individual calderas probably reflect how much of that rhyolite mush was reheated by an initial intrusion of basalt. 0.2 km3 per year is getting into hotspot level magma generation, comparable to hawaii, it is of course not a single volcano but for a silicic system the supply rate is pretty ridiculous.

          The next caldera in the zone is going to be particularly scary though, even by this areas standards of how big things can go and how fast that can happen, because unlike any of the others, it will be on the coast. There has been magma accumulating at about the point where the TVZ enters the ocean for at least the past 1700 years and while its not set to erupt yet or any time really soon the result will be an eruption that on its own would already be a VEI 6+, happening in shallow ocean… think the minoan eruption, or even kikai, that is on the cards here…

          New zealand doesnt have any very active volcanoes (at least not since 1977), but they really go big or go home if things happen.

          • Yup TVZ haves crazy magma supply ( weird since mantle is rather cold in subdiction zones
            Subudction zone hydrous and decompressing melting back rifting in TVZ combination is what produces the high melting in TVZ.
            Yup most other places basalts evolves into ryholites.
            TVZ and Altiplano Puna haves the highest melt supply / melt rates of any subduction zone areras.

            In TVZ the hot basalt is melting the granite to make instant ryholite as you say.

            Buty TVZ lacks Icelands and Hawaiis 1500 C partial melting lens / zone

          • Tarawera 1886 eruption shows there is a very hot mantle under the area though, many subduction volcanoes erupt basalt but its usually not that hot, tarawera was as hot if not hotter than any lava erupted by hawaii or iceland, determined from parts of the eruption being non-explosive so the dike survived, it melted the rhyolite around it and is mostly glassy. Given the magma would have cooled on the way up the mantle under it must have been at least 1300 C, which is comparable to a hotspot and a lot higher than the average for a subduction zone. Its not as hot as hawaii but very few other places actually are either, so its not really much of a comparison, 1300 C is still way above the solidus point of basalt.

          • Thing is a council in Iceland right? That’s government.

            That GEOnet reference has some very calm, schoolchild-friendly explanations of a rather Neapolitan volcanic situation directly beneath Auckland.

            Also if you follow the direction of the Marutaki rift north you get to Raoul Island in the Kermadecs, which is itself a large volcano with a partially submerged caldera.

          • Artists drew a non schoolchild-friendly image of a very bad day for sailing on Auckland Harbour:

          • The Thing… Thats a member of the Adams family or??

            GL Edit: The ambiguity of the name is what I was playing off of though actually I think it is Þing. (we have since lost the thorn character) {Warning, I may even have the case messed up in my use of it. If so, my apologies}

        • In the 1970s the owner was an Auckland stockbroker – one result of the complicated legal legacy left by White Island’s ill-fated sulfur mining past. I’ve only found one other live volcano which is said to be in private ownership – oddly enough, a rather famous one, Vulcano. Maybe just coincidence, but another volcano where commercial sulfur mining/quarrying was attempted

  21. Manam also erupting now. Did someone mention something about contacting VC about a previous post I sent over? Not sure what I need to say / reach out to.

  22. Let’s hope and pray for a VEI 7 eruption to stop the global warming and these associated relentless heatwaves like the heatwave from which Europe is suffering now.

    • Any suitably located very large eruption sufficient to significantly, but temporarily, drop temperatures over large populated areas would be a disaster I do not wish to see.

      Not to mention all the extra fossil fuels we’d presumably burn to keep warm so we’d be in a worse off state down the line.

    • Volcanic winters dont work that way.
      Sure you may get some cooling from the denser plume of particles, but there will also be a plume of lighter greenhouse gasses that warm things up. These plumes will, especially at first, not overlap or be evenly distributed over the planet.

      So you get weather alternating between summer snowstorms and heatwaves. With intense volcanic thunderstorms in between.

  23. OT but a new experimental solar cycle forecast this time from NASA

    Research now underway may have found a reliable new method to predict this solar activity. The Sun’s activity rises and falls in an 11-year cycle. The forecast for the next solar cycle says it will be the weakest of the last 200 years. The maximum of this next cycle – measured in terms of sunspot number, a standard measure of solar activity level – could be 30 to 50% lower than the most recent one. The results show that the next cycle will start in 2020 and reach its maximum in 2025

    …The new research was led by Irina Kitiashvili, a researcher with the Bay Area Environmental Research Institute at NASA’s Ames Research Center, in California’s Silicon Valley. It combined observations from two NASA space missions – the Solar and Heliospheric Observatory and the Solar Dynamics Observatory – with data collected since 1976 from the ground-based National Solar Observatory.

    …Kitiashvili’s method differs from other prediction tools in terms of the raw material for its forecast. Previously, researchers used the number of sunspots to represent indirectly the activity of the solar magnetic field. The new approach takes advantage of direct observations of magnetic fields emerging on the surface of the Sun – data which has only existed for the last four solar cycles..

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