UPDATE: See some amazing images of the recent eruptive activity over on Stromboli Online. {Hat tip to the Volcanism Blog via Eruptions reader CK.}

One event that didn't eat much coverage over the weekend, at least here in the U.S., was the large eruption and explosions at Soufriere Hills on Montserrat. The volcano has had a resurgent winter since have a quiet summer of 2009. This weekend's eruption produced an ash plume that reached ~6.1 km / 20,000 feet - which has been happening quite a bit over the last month or so. However, this eruption produced an large pyroclastic flow that reached the former capitol of Montserrat, Plymouth and 500 meters (not miles as one report states) into the sea. This eruption would technically be a vulcanian eruption according to MVO and prevailing winds prevented ash or lapilli from falling on the eastern half of Montserrat. This eruption was likely related to the collapse of the growing summit dome. MVO has posted a thermal video of a previous vulcanian event on January 7-8, showing the collapse/explosion from the dome and the pyroclastic flow generated - both made of hot (>500 C). The latest information on the current activity from Soufriere suggests that the central western part of the dome was growing steadily before the vulcanian event over the weekend, but there is yet to be another observation of the dome to see if that has changed.

This is a request more related to my teaching, but I thought I'd ask here. I'm trying to find copies of the UNESCO videos "Understanding Volcanic Hazards" and "Reducing Volcanic Risk". They were made by the Kraffts to help educate people on volcanic hazards, especially in developing countries. I've seen them both and they are great for introductory geology classes. However, the one source I knew of - the NW Interpretive Assoc. - doesn't seem to carry them anymore - and even if they did, the only format I know of is VHS, which is getting woefully obsolete.

So, do any of you know where I might be able to get a copy of either/both of these films, either on VHS, DVD or otherwise? Leave a comment here or send me an email at Thanks for any help!

Laacher See, Germany
The Laacher See is a caldera in the Rhine Valley of Germany (see below). It is only ~30 km south of Bonn and ~60 km south of Koln (Cologne), just to the west of the Rhine River. It is part of the East Eiffel Volcanic Field and the 8-km wide caldera is currently filled with a lake. Now, most people don't think of volcanic activity occuring in central Europe, but it is believed that a mantle plume lies below this part of the continent, creating rifting and the volcanism in the Eifel Volcanoes. Laacher See last erupted ~12,900 years ago, but it was a doozy, erupting ~6 km³ (dense rock equivalent, i.e., taking all the ash and compacting the air out of it; closer to 20 km³ of uncondensed) of phonolite (an silica-undersaturated magma found in continental rift zones) tephra, making it similar in size to Pinatubo in 1991. Phonolite tends to have some odd minerals in it, such as the light blue feldspathoid, Hauyne, but the Laacher See magmatic body appears to be a complex mix of crystals from different sources.

The ash from the eruption can be found in the North Sea and throughout central Europe. Some of the deposits found near the caldera is remarkable, and (to me) seem so anomalous for the middle of the German countryside. There is some suggestion that the Laacher See eruption could have had a strong effect on the climate of Europe after the eruption and the human populations living there at the time. Although it has been quiet since the climactic eruption ~12,900 years ago, the caldera should still be considered potentially active as CO₂ seeps exist in some parts of the lake, suggesting that there is still magma degassing under the lake. In fact, the CO₂ can be a hazard, supposedly killing some Medieval monks in their sleep. There is no hazard map for Laacher See.

Here are a few pictures from my trip to the Laacher See (as a part of the 2007 Goldschmidt Meeting in Cologne). Click on the image to get a bigger version.

Pumice from the 12.9 ka Laacher See eruption at the Standort Wingertsbergwand, a quarry near the caldera. Note the trees at the top of the ridge for scale.

This is the plucky mascot that guided us to the deposit.

A close up of the tephra deposits showing the beautiful layers of ash, pumice and lithics. This is a record of the pyroclastic flows and ash fall from the multiple days of the Laacher See eruption.

Another view of the stunning tephra deposits.

Dr. Worner points out some of the features of the tephra deposits.

Dr. Worner uses a hand-made sampling device (i.e., a cut up soda bottle) to gather some of the volcanic gases - mostly CO₂ bubbling up on the shores of the Laacher See. You can see the bubbles in the foreground in the shallow water.

A view across the caldera lake. You can see the Maria Laach Abbey on the opposing shore.

And really, what a better place to end the day than at a Brewery that keeps its beer in an underground basalt flow.

Just a quick note, but I got this email overnight regarding the status of KVERT, the Kamchatka-Kuril Island volcano monitoring body in Russia.

Scientists of KVERT Project return to the full KVERT operations (the
information ensuring of air services for the results of daily analysis
and evaluation of activity of Kamchatka and Northern Kuriles
volcanoes) and will discharge these obligations for 01 February - 30
April 2010.

So, after losing their funding, it has some back until the end of April (based on how I read this). Russian politics as usual? A window to get real funding in place? Who knows, but at least for the time being, KVERT is up and running again.

{Hat tip to Eruptions reader Tsunami for also bringing this to my attention.}

Pakistan is home to the world's tallest mud volcano in the region of Balochistan - and its somewhat near the reports of an "eruption" earlier this week.

• Guess what? Since Wednesday evening, seismicity at Yellowstone has dropped precipitously. The last batch of earthquakes on February 3rd were also back to deeper levels - 8-9 km depth - compared to the potential shallowing earlier in the week. I'm sure the caldera will keep us on our toes, but as of now, it seems to have settled down a bit.
• Over in Pakistan, there is mounting evidence that the recent "volcanic" eruption reported as, in fact, a mud volcano similar to the one reported in Azerbijian yesterday. There can be explosions associated with mud volcanoes as trapped natural gases escape and (potentially) ignite. There is a long history of mud volcanoes in Pakistan, especially in the region where this eruption was reported.
• In case you missed it, frequent Eruptions commenter and part of the Italian National Institute of Geophysics and Volcanology in Catania, Dr. Boris Behncke, was on the Discovery Channel show Solving History. He was talking about Mt. Etna in a part of an episode looking for Atlantis (?) - the segment is called "Volcano Hell" (nice touch, eh?) Sadly, they aren't streaming the part with Dr. Behncke in it (so Boris, has Etna been "wreaking havoc on Europe" as Olly says?) Now, if only someone would give me a call to be on TV... {hat tip to Doug for point this out.}
• The NASA Earth Observatory has a few good images to send us into the weekend. First captures the swirling ash clouds from the revived Soufriere Hills on Montserrat. The second shows the beautiful snow-covered symmetrical cone of Karymsky filling the old caldera that surrounds the new edifice on the Kamchatka Peninsula.
• Finally, lost in all the Yellowstone, Pakistan and Japanese volcano news, the latest USGS/Smithsonian Weekly Volcano Report was issued. One of the interesting things it points out is that after all the activity in January of Nyamuragira, its neighbor Nyiragongo is now showing signs of an impending eruption.
Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/friday_flotsam_yellowstone_slo.php http://scienceblogs.com/eruptions/2010/02/friday_flotsam_yellowstone_slo.php Africa Fri, 05 Feb 2010 04:50:08 -0500
A 2010 mud flow from Lok-Batan, a mud volcano in Azerbijian.

So, first there was all the Yellowstone talk. Then the unsubstantiated reports of a volcanic eruption in a decidedly unvolcanic part of Pakistan (what part isn't), then submarine volcanism off Japan. Now, we have a nrews report about an eruption in Azerbijian. Luckily, although the headline implies a magmatic event, the text of the article shows that this is, in fact, a mud volcano. The mud volcano is called Lok-batan (or Lokbata) and has erupted quite a few times over the last 150 years, as recently as 2005. Azerbijian has quite a few mud volcanoes, some of which are quite impressive. Remember, "mud" in the ground is just a viscous fluid - water and soil more or less - so it too can behave like lava if it becomes pressurized, especially thanks to heating of the mud. Earthquakes (common along the shores of the Caspian Sea in Azerbijian) could provide a route to the surface for the pressurized mud, leading to the "eruption". The most famous mud volcano in the world is like the Lusi Mud Volcano in East Java, Indonesia - a feature that was likely triggered by man-made action.

Quite the volcano week, eh?

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/eruption_in_azerbijian.php http://scienceblogs.com/eruptions/2010/02/eruption_in_azerbijian.php Lok-Batan Thu, 04 Feb 2010 10:14:12 -0500
The plume from submarine volcano Fukutoku-Okanoba, erupting in February 2010.

Almost a year after the Hunga Tonga Hunga Ha'apai eruption, where an undersea volcano sprang forth from the deep - quite spectacularly, we have new footage of another undersea eruption. Fukutoku-Okanoba, off the coast of Minami Iwo, started to erupt yesterday (or, at least, erupt enough to manifest a plume out of the ocean). A Japanese coast guard vessel was able to capture the plume on video as it reached 100 m / ~300 feet. The plume appears to be dominated by white steam along with some grey ash mixed in. Additional footage shows the water stained brown/tan with ash and volcanic debris from the eruption as well.

Fukutoku-Okanoba is actually a quite active submarine volcano, last erupting in 2005. The sea is often discolored near the volcano and a number of ephemeral islands have formed due to its activity over the last 100 years - my favorite being Shin-Iwo-jima, or "New Sulfur Island" in 1904. Most of the eruptions appear to be VEI 0-2 based on what manifests at the surface, however the 1904 eruption was VEI 3, producing significant andesitic (intermediate) ash and lava. The summit of the volcano lies only 14 m / ~50 feet below the ocean surface.

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/submarine_eruption_near_japan.php http://scienceblogs.com/eruptions/2010/02/submarine_eruption_near_japan.php Fukutoku-Okanoba Thu, 04 Feb 2010 08:45:29 -0500 With all the talk of the current Yellowstone earthquake swarm, I thought it would worth it to write a post on the the structure and caldera - and why we get earthquake swarms that are structurally rather than magmatically-related.

First off, lets think about why calderas formed. This is relatively simple - at least superficially. The land (or volcano) above a magmatic system is partially supported by that magma, especially because magma is hot and buoyant. The isostatic support by the magma holds up the land surface or volcanic edifice, so when an eruption expels a large volume of magma, this support is removed. This collapse forms the caldera - the negative topographic expression of the eruption. The collapse of the land surface plays a dual role - not is it a result of the eruption, but also helps the eruption along, like a piston pushing of hot gas out of a cylinder. After the eruption, the collapsed caldera continues to subside as the isostatic equilibrium is reached. After the caldera-forming eruption {caution, large PDF}, the system may have eruptions that produce resurgent domes in the middle of the caldera as the last dregs of the caldera-forming magmatic system leak out. This is referred to as the "caldera cycle", originally defined by Howell Williams for the collapse of Mt. Mazama ~7,700 years b.p. (see below).


Modified illustration of the caldera cycle by Howell Williams.

The collapse of the caldera produced what is called the "ring fracture," the fracture along the edge of the caldera. This fracture was formed during the collapse, but was then likely also exploited by the erupting magma during the caldera-forming eruption. These fractures then become long lived zones of weakness around the edge of the caldera (see below) - the down-dropped part of the caldera is no longer supported by either the emptied magma chamber or the crust around it.


Map of the extent of Yellowstone Caldera. The ring fractures from the caldera-forming eruptions are roughly coincident with the caldera.

We can look at the general structure of caldera systems by looking at the Long Valley Caldera (see below). The ring fracture is present on the edge of the Long Valley caldera, with the down-dropped caldera material in the middle - filled in by the tephra from the caldera-forming eruption and resurgent dome material. The caldera may continue to settle for hundreds of thousands of years after the caldera-forming eruption - all happening at depths at or above the current "top" of the magmatic system.


A schematic look at the structure of the Long Valley caldera in California.

If we take a look at historical seismicty around Yellowstone (see below), we can see that quite a bit it is near the ring fracture of the caldera. This means that thesuggested structural source of the current seismicity makes sense - as I've mentioned, the earthquakes in these locations in historic times have not lead to eruptions. In fact, we should expect to see a lot of low scale seismicity along the ring fracture that represents the many faults related to the ring fracture system.


Historic seismicity around Yellowstone Caldera.

However, as zones of weakness, you might expect that magma could exploit the ring fracture to reach the surface. Magma rising would need corroborating evidence, though. Magma doesn't do a good job of disguising its present, especially large volumes. The ground should deform from the additional volume of magma displacing the crust and this displacement with our current methods of measuring ground changes should be detected well in advance of an eruption. We should also expect changes in the hydrothermal system as the hot body of magma moves higher into the system, possibly in the form of new mud pots, geysers or hot pools. The chemistry of springs might change as well, reflecting the input of magmatic components into the water - which goes hand-in-hand with changes in gases being released by the magma. Volatiles like water vapor, CO₂, SO₂ and He are constantly being released by a cooling, depressuring magma, so we should see the signal of this in the gases being released at Yellowstone, especially by monitoring dissolved gases in springs. The type of earthquakes should also change - not only becoming shallower, but also taking on the classic pattern of harmonic volcanic tremor - the harbinger of moving magma.

YVO monitors many, if not all, of these factors, so we are not likely to be "surprised" by any new eruptions at Yellowstone. While the current earthquake swarm does appear to be getting shallower, you can see how it is part of life at an active caldera system. You can check the current status of the Yellowstone Caldera on the YVO website.

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/the_structure_of_calderas.php http://scienceblogs.com/eruptions/2010/02/the_structure_of_calderas.php Yellowstone Thu, 04 Feb 2010 04:07:55 -0500
Steaming, gurgling mudpots in the active hydrothermal system of Yellowstone.

For those of you following Yellowstone (I think there might be a few of you), I've plotted up the earthquakes since 1/27 (see below) - and sure enough, although there is a lot of scatter, they are getting shallower - however what this exactly means is unclear. You can see my plots from 1/22-28 here. As many of you have mentioned, a caldera like Yellowstone is a big interconnected system, so a solely tectonic source of this is still possible as the displacement migrates through the fractured caldera rocks.


UPDATED: Now with error bars! The line divides the well constrained (to left) from the poorly constrained (to right).

This all being said, YVO's current status statement still reads:

" At this time, YVO scientists and their collaborators have detected no anomalous ground deformation, strain, or increased thermal activity that could indicate precursory activity to phenomena such as steam explosions or volcanic eruptions. As such, the Volcanic Alert Level remains at Normal (Aviation Color Code of Green)."

So, again, without abundant evidence to suggest otherwise, the swarm has shown no indications that this is magma related. The earthquakes are shallower right now, but again, we need to look at this information with an abundance of caution. YVO posted yesterday a summary of the current earthquake swarm and an brief history of swarms to put this one in context along with a description of all the monitoring that occurs at Yellowstone - so if you are concerned about the swarm, be sure to check it out. This caldera is not solely a magmatic feature - the process of caldera-forming itself involves breaking the crust along a ring fracture. This means that the area is littered with thousands (millions?) of fault systems related to the caldera. Trust me, I'd be fascinated by the idea that a new dome might be erupting at Yellowstone (i.e., NOT A SUPERVOLCANIC ERUPTION), which is the mostly likely scenario, but until the evidence tells me otherwise, this doesn't look like it.

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/the_yellowstone_earthquake_swa.php http://scienceblogs.com/eruptions/2010/02/the_yellowstone_earthquake_swa.php Yellowstone Wed, 03 Feb 2010 08:56:10 -0500 UPDATE 2/2/2010 7:30PM EST: Another report, this time placing the activity near Wham. This report is still vague about that is actually happening, saying people saw "flames of burning rocks on the top of the mountain over the last couple of days". The article also says the Headquarters of the Geological Survey of Pakistan has not returned any inquires on the event. My guess (and I emphasize guess) is this might be a misconstrued forest fire ... but this is about as strange a report of a volcanic eruption as you can get.

UPDATE 2/2/2010: A little bit more detail - the "volcano" in question is called Torghar Mountain. There is a blurry, unidentifiable picture that sort of looks like a scoria cone deposit or spatter cone deposit in another report that says the "eruption" started on Sunday night.
---

Anybody want to help me on this. I just read a report of a volcanic eruption in Pakistan. Here is the link to the report, which offers few details, including, well, the country that this is happening. I'm guessing it is Pakistan based on the source and the names.

The full report:


A mountain in Charri located near Ziarat has begun to spew molten lava, creating panic and fear in the locality.

Talking to journalists, DCO Ziarat Siddiqui Mandokhel said that that he had personally surveyed the site of occurrence, and said that emittance of chemical gases had begun last night, after which it spewed out a molten lava, the size of a meter.

He also said that that special (scientific) survey teams would be arriving soon to study the lava, which had thankfully not reached any credible population in its environs; which is already scarce.

He assured that despite all natural immunity, safety measures had nevertheless been taken, and a fewer homes located in the environs of site, have been or were in process of being relocated.

It is pertinent to note that during last year this region had been subjected to severe seismic jolts, resulting in calamitous loss of lives and property; while aftershocks are still continuing.

Seismologists have already marked the region being in quake zone (redzone), while locals are fast relocating, due of any further anticipatory calamity.

I'll try to find more information, but this is a big question mark to me right now.

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/volcanic_eruption_in_pakistan.php http://scienceblogs.com/eruptions/2010/02/volcanic_eruption_in_pakistan.php Pakistan Tue, 02 Feb 2010 14:54:25 -0500

I've been seeing a lot of questions popping up in the comments - and for me, I find it difficult to answer them in the confines of post comments. Many of them are quite good and would probably be of interest to lots of Eruptions readers, so I thought maybe it is time for another Eruptions mailbag post.

So, without further ado, email me your burning volcano-related questions! Send them to by February 15, and I'll try to answer as many as I can in a mailbag post.

Looking forward to your questions!

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/eruptions_mailbag_call.php http://scienceblogs.com/eruptions/2010/02/eruptions_mailbag_call.php Eruptions Blog Tue, 02 Feb 2010 12:35:16 -0500
Tungurahua erupting in an undated AP photo (although I think it is the current 2010 activity.)

It hasn't really made it to much of the English-speaking news, but the current eruptive activity at Tungurahua appears to be on the up-tick. Hugo Yepes of the Geophysical Institute of Ecuador suggests that a larger eruption is not out of the question (link in spanish), but right now the activity is confined to explosions (vulcanian?) and ash fall around the region, specifically on Pillates and Choglontus overnight (2/1) from the ~ 2 km / 5 000 foot plume. Looking at the specifics (link in spanish), the Geophysical Institute is reporting 32 explosions, 30 long-period seismic events and 20 episodes of volcanic tremor in the last 24 hours. Government officials have issued a number of warnings for people living near the volcano and began preparation for evacuations. You can listen to Hugo Yepes report here (in spanish).

One of the few articles in English media regarding Tungurahua was a report about the difficultly of getting people to evacuate in these situations. We've heard this before, where people don't want to leave their home/farm because thieves will steal their meager possessions and livestock. Now, that might seem crazy to you and me, to be (as one of the commenters on the article says) more worried about possessions than life, but many of the residents of this area in Ecuador live a very scant existence, so losing their livelihood (such as their animals) is tantamount to, well, death.

{soapbox}This is where the rose-colored glasses of Americans and Europeans is most maddening - these people literally have nothing if they lose their home or livestock. It is not like they have insurance on their home, or well-off parents to support them if they fail or even a rich government to kick in disaster relief money. So, sometimes you have to roll the dice and think that the likelihood of getting killed by the volcano is smaller than getting robbed if you evacuate - and in all honestly, most of the time the former is less likely than the latter. The problem lies in the few times that you're not right - and that is the part that volcanologists try so hard to predict. It is not like they enjoy calling evacuations when they are not needed, but right now our ability to pick out the exact last moment before you should evacuate is not too sharp - it is close to trying to do surgery with a sword instead of a scalpel. Sure, it might get the job done, but the collateral damage ... The long and short here is that there is much of the world where the decision-making process you might have when you evacuate your nuclear family from your beach home in Wilmington NC for a hurricane - when you can pack your car with possessions and lock the doors and set the alarm for your possessions (but not your livelihood, because you don't live off the land of your home or have livestock most likely) is very different than someone evacuating on foot with what they can carry (most likely not much) with their children and extended family. {/soapbox}.

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/activity_increasing_at_tungura.php http://scienceblogs.com/eruptions/2010/02/activity_increasing_at_tungura.php Tungurahua Tue, 02 Feb 2010 09:07:58 -0500 First off, I wanted to thank all of the Eruptions readers for making January the most popular month ever on this blog. I suppose I should give an assist to Yellowstone, but really, thanks for coming to the blog, reading the posts and engaging in all the great discussions that go on within its (cyber)walls.


Kīlauea's east rift zone eruption site. Image courtesy of the USGS/HVO.

On to some news!

• I suppose you've made the big time when you're in the New York Times, and sure enough, the current Yellowstone earthquake swarm is in the Old Grey Lady. Nothing much new to read, but summarizes the current USGS and Utah stance on the current seismicity. The earthquakes continue to march along, but still at the same depth and location.
• Now that Turrialba seems to have come back to life after over 100 years off, Costa Rican officials have outlined exactly where the risk lies around the volcano. They've divided the area around the volcano into zones of danger, with the immediate 2 km closest at the highest hazard, especially for ash and volcanic gases during this phreatic period of eruptions. The volcano currently sits at Yellow Alert status, 2nd on the 3-level alert system for volcanoes in Costa Rica.
• Here is a nice summary of the current activity at Kilauea as the volcano enters its 28th year of eruption. Most notable is, of course, the lava lake/river in the Halema`uma`u Crater.
• KVERT might be in trouble, but at least the NASA Earth Observatory can keep an eye on some of the volcanoes from space. This new view of Bezymianny shows how similar its crater is to Washington's Mt. Saint Helens.
• And leave it to our friends at Fox News to release an article on how to visit erupting volcanoes. I'm really not sure where they got the numbers for the opening paragraph and the article drifts off from volcanoes somewhere in the middle, but hey, if you wanted a list of fun places to visit, here it is.
Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/02/monday_musings_hazard_zones_at.php http://scienceblogs.com/eruptions/2010/02/monday_musings_hazard_zones_at.php Yellowstone Mon, 01 Feb 2010 08:47:56 -0500 Some news for the last Friday in January:


Volcanic lightning captured over Redoubt in March 2009.

• Tungurahua in Ecuador continues to erupt. Yesterday, the volcano spread ash over much of central Ecuador. Apparently people in Ecuador aren't taking the hazard of ash too seriously, with many ignoring recommendations to wear masks when the ash is falling. Over 50 explosions have been recorded over the last 24 hours at the volcano according to the Ecuadorian Instituto Geofísico, most of them small to moderate.
• We also have a new USGS/Smithsonian Institute Volcano Activity Report. Much of the "new" news is on the continuing activity at Soufriere Hills and Tungurahua, but they also have reports from India, Chile, Russia and beyond.
• Got some excess CO₂ to sequester? Apparently vesicular basalts might work as a place to keep them - provided they are underwater and covered with sediment.
• The Redoubt eruption in March 2009 has given scientists at AVO a chance to study volcanic lightning - and identify it as a new kind of lightning. Instead of forming within the ash column/cloud itself as has been seen before (and caused by ash in the eruption), this lighting was sourced from the vent itself - yes, the volcano was producing lightning. Technically, it was still the static electricity stored on the ash particles, but this new source of lightning had not been identified until now. (hat tip to Jim Wiebe.)
Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/01/friday_flotsam_volcano_lightin.php http://scienceblogs.com/eruptions/2010/01/friday_flotsam_volcano_lightin.php Redoubt Fri, 29 Jan 2010 03:31:23 -0500 There has been a ... ahem ... healthy discussion of Yellowstone's current earthquake swarm on Eruptions as of late. We've now reached ~1,500 measurable earthquakes over the last 11 days. The latest reports of the continuation of the swarm isn't going to make anyone happy, but still, there are no signs that (a) this is out of the ordinary and (b) indicates magma making its way to the surface. In fact, if you plot the earthquakes since the 22nd of January, the depth appears to getting, well, deeper:



This plot shows the earthquakes listed on the USGS earthquake page since January 22 (oldest to left, youngest to right) plotted against depth. If anything, the earthquakes seem to be becoming more restricted in their depth around 10-10.5 km and definitely not heading upwards. This is not to say that they won't, but with the evidence right now, the earthquakes seem to be pretty stably around 10-11 km depth. That, to me, seems to back up the USGS/YVO assertion of a tectonic origin - faults at depth (more or less) - rather than magma/liquid moving towards eruption (combined with the fact that the earthquakes are staying approximately the same magnitude range ~ 1-3).

However, you never know with a system like Yellowstone - nothing can really be considered "unrelated" to the caldera and we don't have a lot of evidence of how large caldera systems might behave before an eruption. However, remember, Yellowstone is just a big caldera - and we have experienced other caldera-related eruptions like Katmai/Novarupta in 1912 and Chaiten in Chile in 2008 - we're definitely not working with no idea what to expect. We can also model the potential types of behavior of a caldera if it were headed to eruption to at least give us an idea of what might happen, seismically speaking, if an eruptive sequence was beginning.

This earthquake swarm is clearly fascinating and well worth our time and attention. However, delving into conspiracy theories and fear is definitely not the way to go. I'll try to stay on top of the unfolding events, so watch this space if anything changes!

Read the comments on this post...]]> http://scienceblogs.com/eruptions/2010/01/taking_a_look_at_the_yellowsto.php http://scienceblogs.com/eruptions/2010/01/taking_a_look_at_the_yellowsto.php Yellowstone Thu, 28 Jan 2010 21:07:38 -0500