Wrangell Volcanic Field

Image001.jpg – 1024 x 642 pixels - Panorama with Wrangell on the left and Drum on the right  --  http://pubs.usgs.gov/dds/dds-39/album.html

Panorama with Wrangell on the left and Drum on the right — http://pubs.usgs.gov/dds/dds-39/album.html

The Wrangell Volcanic Field stretches from the Yukon Territory, Canada northwest into central Alaska. Total coverage of over 10,000 km2 from 12 major eruptive centers. Ages range from 26 MY to around 200,000 years ago, with the most recent activity being toward the western end of the field. There are a pair of volcanoes identified on the Canadian side with the rest being in Alaska. The volcanoes are for the most part andesitic – basalt shield volcanoes, topping out in some places over 5,000 m. Several are topped with what are thought to be subsidence caused calderas measuring 4 – 8 km in diameter, not unlike calderas on top of Hawaiian volcanoes. Wrangell itself is topped with active fumaroles and last erupted in 1930. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Wrangell

Three of the eruptive centers are thought to be stratovolcanoes. One of these, Mount Churchill is the probable source of the largest eruptions in North America in the last 2000 years, when a pair of eruptions around 100 AD and 860 AD deposited over 50 km3 of pyroclastic flows in two lobes called the White River Ash.The source of one lobe has been directly tied to Churchill. The other source is not so well defined, and it may be out of Churchill or its close neighbor Mount Bona, though the 3 km wide caldera sits between both peaks, this may be a distinction without a difference. Other than the White River Ash, there is not a lot of pyroclastic debris along the volcanic field. All mountains are capped with glaciers and ice caps year round. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Churchill,+Mt

Tectonics

From their products and structure, it is clear these are not normal subduction volcanoes along a typical volcanic arc. In order to understand what is going on, we need to take a look at how the region was formed. The majority of the following can be found in “A Geologic Guide to Wrangell—Saint Elias National Park and Preserve, Alaska” by the USGS in 1999. http://pubs.usgs.gov/pp/p1616/

Wrangell – St. Elias is the location in southern Alaska where the Pacific Plate has deposited chunks called terranes onto Alaska. As you travel westward from the Canadian border, these terranes are smashed up against one another much like India has smashed into the underbelly of Asia causing significant deformation and uplift.

In this area, no less than seven different terranes have been identified, with the Yakutat being the most recently delivered. The terranes have been accreting into Alaska for over 200 million years. Each suture is bounded by fault lines, which in turn release compressive energy in the form of strike slip or subduction earthquakes. As you travel west from the Canadian Border, the tectonic forces change from accretion to subduction we see along the Alaska Range and Aleutians.

The terranes are composed of a wide variety of material including Pacific Ocean crust, detritus from erosion into the ocean, islands, and chunks of the North American continent. The motion of the Pacific Plate is generally north to south along North America, with portions of the continent on the west side of the fault line moving north. It has been observed that Los Angles will sit abeam San Francisco in some 30 million years. Eventually, plate movement will deposit that part of the continent onto southern Alaska.

Terrane Boundary – Wrangell – St. Elias Alaska  --  http://www.largeigneousprovinces.org/08dec

Terrane Boundary – Wrangell – St. Elias Alaska — http://www.largeigneousprovinces.org/08dec

When the terranes reach Alaska, they behave in a variety of ways. There has been some subduction, which is blamed for providing the volume of melt necessary to build the huge volcanoes of the Wrangell Volcanic Complex. But the majority of the mountains are andesitic – basalt shield volcanoes – huge ones, at that – which is hardly the product of subduction volcanism with highly evolved magmas. There is comparatively little pyroclastic output in the region. I have yet to find a good explanation for the question. I am used to basaltic shield volcanoes being intra-plate, hot spot related, or spreading rift vents. None of these apply here.

Once the terranes have been deposited, they continue to be pushed and deformed by the compressive action of the Pacific Plate movement. They deform. They slide against one another along the fault lines that separate them. Some of this movement is quite large, with one terrane estimated to move over 250 km to the west since arrival. The entire region is bounded at the north by the Denali Fault, which is one of the major fault structures in North America. It sits roughly east – west along the northern edge of the grouping of terrains and is a strike – slip type of fault. The area is wracked by significant earthquakes in 7 – 8 Richter range. Measured displacement is as much as 14 m uplift following a series of quakes in 1899.

The last major quake on this fault was a 7.9 Richter quake in 2002. It was widely felt statewide and its effects showed up in water wells far into the Lower 48 states of the US. The maximum movement along the fault was just over 9 m. It was strongly felt in Anchorage, some 280 km south. Duration was up to 3 minutes in Fairbanks. I rode it out at a Costco store in Anchorage. The large lights swung back and forth for a long time. The fault line also crosses the TransAlaska Pipeline System (TAPS) perpendicularly. No oil was spilled and the pipeline was briefly shut down. http://pubs.usgs.gov/fs/2003/fs014-03/

The interesting thing about this quake was that the seismicity of Mount Wrangell diminished as much as 80% for the next five months, with quakes ascribed to magma movement diminishing. The seismicity never did recover, indicating something changed with the quakes. The best guess – and it is really a guess – is that the massive movement along the fault somehow disrupted the supply of new magma to the volcanoes. This quake was preceded by a 6.7 Richter quake in the vicinity about 10 days before. http://www.revistas.unal.edu.co/index.php/esrj/article/view/21259 http://www.aeic.alaska.edu/input/steve/PUBS/ssa04602_wrang_DFE.pdf

The Volcanoes

Initial eruptions began some 26 MY ago as the Pacific Plate subduction reached the point where melt started reaching the surface. The angle of the plate and the rate of subduction increased some 5 MY ago, at which time most of the western volcanoes started being built. They grew very quickly with massive outflow of andesitic basalt lavas. Around 200,000 years ago, the majority of the eruptions stopped. Geologists do not have a good explanation for this reduction in activity. The eruptions out of Mount Churchill 1,800 and 1,200 years ago were pyroclastic in nature, indicating evolved magma.

Current activity includes active and vigorous fumaroles out of Mount Wrangell. There were some phreatic explosions over the last couple centuries, but the area is so isolated that it is difficult to establish what happened, why and most importantly when. It does not help that the entire region has been designated national park and wilderness area, keeping all but the most determined amateurs out. There is also a number of hot springs and hot spring powered mud volcanoes (not natural gas powered) in the vicinity of Wrangell. As with all glacially covered volcanoes, any activity will create significant lahars down into surrounding valleys. http://www.uaf.edu/files/aqc/way-wall_CJE2002.pdf

Mount Wrangell is a 4,300 m high andesitic shield volcano. Youngest volcano with activity from 750,000 years ago to near present. Total volume of the mountain estimated at over 900 km3. Capped with a 4 by 6 km caldera as much as 1 km deep. Caldera thought to be formed by withdrawal of magma. Several smaller cones on its flanks. One lava flow as far as 58 km from the volcano, indicating a large rate of eruption. Active fumaroles. Evidence of flank collapse. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Wrangell

Mount Sanford is nearly 5,000 m tall. Visible next to Wrangell. Current peak is young, and connects three earlier smaller volcanoes. Also andesitic – basalt. Active from 900,000 – 200,000 years ago. Completely glacially covered. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Sanford

Mount Drum is the farthest south of this group. 3,600 m peak constructed by andesite, dacite and rhyolite 650,000 – 240,000 years ago. Evidence of explosive, cataclysmic eruption that destroyed an ancestral cone that was later rebuilt. That eruption deposited over 7 km3 on surrounding territory. Multiple domes and pyroclastic debris. This one is a stratovolcano. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Drum

Additional volcanoes to the west of these include Capital, Jarvis, Tanada Peak, Skookum Creek, Gordon, Blackburn, and a series of volcanic vents in the Western Wrangell Volcanic Field. Most of them are not visible from the sparse road system. All are covered by the ice field covering the closely spaced very tall volcanoes. All measure in the vicinity of 4,000 m tall or taller. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Monogenetic%20QT%20vents%20of%20WWVF

Mount Churchill and Mount Bona, are a pair of stratovolcanoes with a 3 km caldera in the saddle between them. Height of some 4,800 m. Source of White River Ash, as much as 50 km3 pyroclastic flows from two eruptions less than 2,000 years ago. Ice and glacier covered. http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Churchill,%20Mt

Conclusion

This is a geologically interesting part of Alaska, and perhaps the newest part of the state. The continuing accretion of new terranes drives earthquake activity which in turn open and close access to melt from subduction and elsewhere. The majority of these volcanoes are locked up within a massive wilderness area and all are covered with glacial ice fields, so data gathering is difficult at best. The reason for the cessation of significant activity 200,000 years ago remains a mystery. The explanation for massive andesitic basalt volcanoes fed by subduction is also a significant question, for me at least. But they are stunning to drive by.

Agimarc

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129 thoughts on “Wrangell Volcanic Field

  1. Earthquake news: a few small M5-6 earthquakes strike Nicaragua for third day within a week. Fears these could be a foreshocks for a larger quake.

    Last time I saw these happening, a few M5 or M6 quakes hitting within a few days was in Chile a few weeks ago, just days before the larger quake.

    Also, these last days, there have been two M7 quakes in the Solomon Islands.

    These do not mean foreshocks per se, but that possibility exists.

    • In regards of the Solomon Islands, that was the main shocks. Solomons has a theoretical maximum yield around M8, and at M7.8 and M7.6 this would be it.

  2. Very interesting Agimarc!
    Looking at the earthquake distribution of the past 45 years the Wrangell-volcanic-field sits amidst a huge oblongated seismic gap, on the border of the subducting plate. Perhaps this is the area where deep magma is capable of rising in large quantities, thus the basaltic component.
    IRIS map: http://tinyurl.com/p3ygkk7

  3. FYI Carl ************** Rock in your mailbox ******************
    They concern Hekla quake(s) last night, 12 km depth 3 km Norh of summit
    that is almost directly under FED SIL station 😉
    I think Hekla almost did it !
    (swarm 10-12 km south of Hekla this morning : I know)

    • Very interesting with earthquakes both there, at the southern end of the fissure and also an unusual swarm at Vatnafjöll. My ears are perked.

  4. Thanks again Agimarc, you rock!, very vividly explained article!
    I had read about terranes a time ago, and now wanted to know what’s the difference between them and microplates. According to this page, it is only a matter of definition, however terranes are now thought solely to be former chunks of plate firmly integrated into continents and surrounded by faults. Still, the terms seem to be a bit spongy to me.
    http://geology.about.com/od/platetectonics/g/About-Microplates.htm

  5. Great post. flew by the Wrangells on a fire call to the interior. never forgot looking
    UP at 12,000 ft. msl as we flew by in or now itty bitty DC-7..
    BTW there is Wrangell terrane in the Seven Devils of Idaho…

  6. Great post about a very interesting volcanic area. Here are some of my thoughts:

    “Other than the White River Ash, there is not a lot of pyroclastic debris along the volcanic field. All mountains are capped with glaciers and ice caps year round.”

    -I’m sure all the geologists have done their homework, but I wonder whether the effects of glaciation ending has served to mask some of the larger eruptions that could have taken place long ago. As common sense would dictate, if all the erupted ash / pyroclastic flows are deposited on top of glaciers that have since melted away, that eliminates a huge portion of geological history. At the same point, some of the current glaciers are likely quite old, so I would imagine they’ve probably encapsulated enough of the geologic history of at least the past 10,000 years, but I wonder how accurate they are after that time period.

    “But the majority of the mountains are andesitic – basalt shield volcanoes – huge ones, at that – which is hardly the product of subduction volcanism with highly evolved magmas.”

    I actually believe you’re a bit off base here. If I remember correctly, almost all volcanic magma starts out initially as basalt (at depth). The primary reason that you get more evolved and explosive magma at arc-based volcanic belts is largely due to the magma evolving on the way up to the surface along with mixing with continental rock & crust. Continental crust also forms a very strong lid, which is better for creating magma chambers and keeping pressurized magma inside while it can evolve. Island based volcanic settings such as Iceland & Hawaii erupt basalt largely due to the fact that the surface is comprosed mostly of weak basalt, which makes it difficult for the magma to stay in one place for a long enough time to evolve past it’s basaltic origins. Since it’s punching through oceanic crust or hardened basalt, there is very little inter-mixing as well.

    Basaltic-andesitic volcanoes are actually quite common in arc-based volcanic settings. Merapi, Fuego, Klyuchevskoi, Colli Albani, Mayon, and quite a few other well-known volcanoes are basaltic-andesitic. I do believe there is more than just subduction going on here, but being basaltic doesn’t by itself imply that its not subduction or arc-related.

    • cbus20122 – Very likely to be completely off base and looking forward to my continuing education as folks here at VC kick me back into play. (tongue firmly in cheek)

      Agree that evolved magmas tend to be explosive, but don’t think that is the entire story, as the subduction process also carries a lot of water into the mantle with the subducted plate. As i understand it, it is the combination of the evolved magmas and the amount of gas (primarily water) in that magma that drive the viscosity & explosiveness of what comes out. You get less of either or both, you get a more effusive eruption, at least up until the point where the magma encounters water.

      In the continental US, NM volcanism is primarily basaltic, little water, apparently out of weak spots in the crust. In CO, it was primarily pyroclastic, with numerous calderas, tied to a chunk of the Farallon Plate under North America.

      I continue to be confused about the relative dearth of pyroclastic output in Wrangell. If there is a subduction process taking place, there ought to be a lot of water in the melt.

      There are stratovolcanoes in your list – Merapi & Klyuchevskoi & Mayon, for instance. They have erupted some basalt, but have built the prototypical stratovolcano cone, meaning some significant percentage of pyroclastic output.

      Not saying this all that well, but appreciate your observations and discussion. Cheers –

      • Just within the cascade range, there are at least 6 basaltic shield volcanoes alone. These are all subduction driven basaltic shield volcanoes.

        Mt. Belknap
        Davis Lake
        Newberry
        Medicine Lake
        Indian Heaven

        No doubt water + gas content is the major driving force behind explosive eruptions, but the point I was trying to make is that you can’t really draw conclusions on the driving forces of volcanism based off how evolved the magma is or isn’t. I don’t mean this as a big criticism of the post by the way – it was really well written, and it’s probably true that the wrangell field is driven by some different processes, but that’s mostly since it’s fairly far from the primary Aleutian subduction trench. I can see this area being somewhat similar to that of Clear Lake Volcanic Field, where rifting is caused by the really messy tectonic environment in the area.

  7. From Whack or Peek at Ya….

    North American indigenous peoples have cultures spanning thousands of years. Some of their oral traditions accurately describe historical events, such as the Cascadia Earthquake of 1700 and the 18th century Tseax Cone eruption.

    Note: I don’t think the “First Nations” are the first. I hold that Clovis was here first (and were a follow-on of Solutrean technology), that were supplanted following the decimation of the Younger Dryas. But… that tends to upset the pedestal that some tribes have placed themselves upon, and the idea is vociferusly attacked. Just look at the gnashing of teeth over Kenniwick Man. After all, you can’t have a Caucasoid (initial identification) wandering around the Pacific Northwest 8400 years ago. That doesn’t fit the meme and upsets the apple cart. No, I don’t think Kenniwick Man was the last Clovis person. In my opinion, he could have been ancient Japanese/Chinese, or a Finn that got lost. I haven’t seen anything specifically identifying his genetic origin. I picked “Finn” because anecdotally, of all the Scandinavian peoples, they would be the ones stubborn enough to keep going.


    The Tseax Cone was the source for a major lava flow eruption around the years 1750 or 1775 that travelled into the Tseax River, damming it and forming Lava Lake. The flow subsequently travelled 11 km (7 mi) north to the Nass River, where it filled the flat valley floor for an additional 10 km (6 mi), making the entire lava flow approximately 22.5 km (14 mi) long.

    http://en.wikipedia.org/wiki/Tseax_Cone

    Google Earth Link

    Terranes are cool. They are the geological equivalent of bugs on the windshield. If you dig far enough, you’ll find that Wrangellia is just an all encompasing term that groups about three separate terrane accretions into one family. A series of three mountain ranges separate the phases as various oceanic plates were driven under North America. The Juan De Fuca/Explorer/Gorda are just the latest.

    A collection of pages at PNSN regarding Native American Stories compiled by Ruth Ludwin, research seismologist, PNSN.

    http://www.pnsn.org/outreach/native-american-stories/native-american-stories-overview

  8. Interesting story yesterday night around Hekla region.

    First a small 0.6 but deep quake right on at Hekla at 22:57. 12km deep.
    Two minutes later, a second quake hits much more west, already at the edge of SISZ.
    A few hours later, a swarm starts at Vatnafjoll, which is only 12km south of Hekla. It starts with a reasonably big M2.9 and then goes on for about an hour. All about 8km deep.

    Of course, supposedly these events are not connected. But I do think that strain at one region is triggering release of tensions elsewhere around.

    • I agree, I would not even rule out some sort of magma pulse, but how and why it got started right now is beyond me.

      • Its not starting now. Its been ongoing (slow) last three years. As you said, best “ordinary” option be normal Hekla, worst… 10 km3 of liquid, spread thin covers lots of ground.

        • That option would count as bad… Last time it happened it ran all the way to the ocean. People really overlook how massive Vatnafjölls eruptions used to be. But during the last 12 000 years only Veidivötn outpaces Vatnafjöll in effused lava and flood basalts.

          • Yes, I agree, bad, bad, bad, bad and bad.
            Thats considering this of one of the south lo-lands finest and smoothest. Not many riverbeads to fill. Lots of farms, nearer to Hella area, or Hvolsvöllur.

            • If the flood basalt goes to the east of Vatnafjöll it would probably do weird things with the riverbed that the Eyjafjallajökull Jökulhlaup took. And that might give other problems next century or so when Eyja goes again.

            • humm. but it can not go that way, higher ground between Tindfjöll and Torfajökull assure that. So everything goes south-west, as the water (and rivers/stream) flows. Gravity. Physics 101 😉

            • That is why we are happy to have locals correcting us outsiders when we make mistakes like that.

            • ☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣
              Which would make those papers concerning the SO2 output of flood basalts to be worth a re-reading. My interest is in what percentage of Carbonyl Sulfide would be in the emission. That’s has the long term capability of affecting the Junge Layer in the months afterwards. Remember, it takes about 50 months for the Sulfate to precipitate/sediment out of the stratosphere.

              Volatile fluxes during flood basalt eruptions and potential effects on the global environment: A Deccan perspective Self et al (2006)

              I think [x] Rx sums it up nicely… 😀

            • Yah, pretty much, though the “bitch” concept is what I was going for. Mainly directed at the “we know all” community with regards to climate.

              In other words, “Here’s a curveball, deal with it”

              IMO, Nature is really good at hurling curveballs. BÖC even references this in their song “Gozillza” → “History shows again and again how nature points up the folly of man.”

            • We only have to look at an outline of Iceland to see the effects of recent lava flows. The oldest parts of the shore, to the west for instance, are ragged with inlets and fjiords, while the southern coastline is smooth and new.

            • With regards to that Carbonyl Sulfide from a flood basalt. The biggest difference between myself and most of the “we know all” community, is that I fully acknowledge that I can be flat out wrong. After all, I am human. We are allowed to make mistakes. In order to really screw things up beyond all belief, you need a Government.

            • ” We are allowed to make mistakes. In order to really screw things up beyond all belief, you need a Government. ”

              Kind sir, please accept my virtual handshake for the quote of the month. 🙂

            • Hm, stupid people and large groups…

              The Meerkat is the brightest non-hominid, quite possible the brightest not counting us humans. They are together with humans and Bonobos the most social and cooperative animal. Among their inventions are daycare-centers for babies and elder-care centers. They have a language and use tools. On top of that they have an amazing ability to cooperate to solve difficult tasks. They have even come up with a rather ingineous solution to the opposable thumb issue.
              If and when we humans go to poop these lovable little rascals are the most likely candidate to take over the show.

              And the thing with groups… They can pretty much beat any animal to pulp by mobbing them in group. The snake on the picture is just a quick lunch for them.
              And, if you try to make a pet of them they will quite literally take a piss on you and run away.

            • “they will quite literally take a piss on you and run away.”

              Sounds a lot like a politician.

            • Carls comment about meerkat intelligance reminded of an incident that happened many years ago, in a supermarket, shopping with my wife. I was deciding what best lamb chops to choose when she said:
              “Your a hypocrite, if octopus is for sale in the fish section, you always go straight to the red meat!”
              And, as wives are always correct, I could only grudgingly smile and admit she was right (as usual!)
              Octopus is the one animal on Earth that has always facinated me. It’s like they are born with intelligance, but their lifespan is so short it prevents them getting any further than, well, appearing on the fish market.

              “Octopuses have a relatively short life expectancy, and some species live for as little as six months. Larger species, such as the giant pacific octopus, may live for up to five years under suitable circumstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch. They neglect to eat during the (roughly) one-month period spent taking care of their unhatched eggs, eventually dying of starvation.”
              http://en.wikipedia.org/wiki/Octopus
              What facinates me about them is what they can achieve over a very short lifespan.
              http://www.thecephalopodpage.org/smarts.php
              and how we can, if they allow, interact with them.
              http://www.orionmagazine.org/index.php/articles/article/6474/

  9. I notice that once a “measles” outburst spreads over Iceland, at least on small earthquake happens in some of Iceland’s volcanoes.
    My question is – is there a relation to one of these “measled” moments having interfered with the “awakening” of any one of them (Hekla included)?

    • Measles shift the strain so it probably helps to induce volcanic quakes. But awakening a volcano? Not really.

        • Yepp, I heard someone wisper Eyjo did not empty compleatly compleatly… so we could get another cloud .. in hundred years …

          • Wasn’t that the case for the 1821 eruption as well? Some of the lava sitting in Eyjafjallajökull would not be anything new according to volcanologists..

  10. The undiscovered Joke…

    In this video, allegedly a blooper clip, the joke and ridicule is the inability to pronounce Trigonometry. What they missed is that Roy Clarke has done much worse by using the word “Bigotry” which has a far different meaning than “Bigamy,” which is what is intended in the script.

    Careful Roy, your prejudices are showing…

  11. Thanks for a very informative post Agimarc! Learnt a lot from you. Meanwhile…watching Hekla again. I just hope I don’t end up staying up to 3:00am UK time once again waiting….

    • I can second that remark. A very informative post about a range I know nothing about. I’m also Hekla watching. 🙂

    • Well, lets face it: If it werent for that news about Hekla being “full and ready”, 90% of people wouldnt even notice the quakes at Hekla, let alone wait up all night for a possible eruption. 🙂 Considering the morning swarm wasnt even in the Hekla system, there were only 2 quakes today actually in the Hekla fissures. Tho I have to agree that it is a long night, and there is more then enough time for Hekla to go from sleep to party. 😀

      • need point out, although “quake” at Hekla 22:57 hrs (local) last night is registered in list as “only one” very small quake – it actually was over eight** microquakes, spread over 5 minutes.
        Volcaholic wet dream! I bet some few extra work hours be needed analyse that!
        *excuse the language*
        ** might be more.

  12. And now the dead zone at 20:29:30, 19.5 km deep, magnitude 1.1, 20.4 km WSW of Laki.
    Caveat, bad quality yet.

          • Well, I may have written it, but I am in no way an expert. Remember, my contention is that the silence is due to the malleability of the rock in the underlying old fissures accommodating the stress.

            But… ponder this. A Normal mode fault of Mag 3.0 would yeild a max displacement of about 0.6 cm and have a down dip rupture width of about .81 km. That could start a venting if there is enough pressure down there. Mag 5.0? 3.55 cm displacement with a down-dip width of 4.17 km.

            I think that the 1783 Lakagígar was presaged by a series of Mag 5.0 quakes. This is from working backwards from the reported shaking in a few towns at the time to what sort of quake would yield that effect from a quake down in the Laki area. I used the paper behind the USGS’s “Did you feel it” program. (Atkinson-Wald).

            Time will tell.

            • There was another Dead Zone quake about a week and a half back, I don’t think it was mentioned in here.

            • Does not scare me, I am here and can do nothing about beiing “near”. But I fear no, and let it come. That be the day I get rather busy.

            • That means that you are “it” then. That personification of human that gets presented with a difficult situation, grits his teeth, and just deals with it, much like the hominid adult taking a child by the hand and plodding off to safety.

              The footprints themselves were an unlikely discovery because they are almost indistinguishable from modern human footprints, even being almost 4 million years old. It is noted that the toe pattern is much the same as the human foot, which is much different than the feet of chimpanzees and other non bipedal beings.

            • I just hope I will be able to get there before the airlines shut down completely. I would though bring my gas-mask and an ample supply of extra filters and to hell with what the security people at the airport thinks.

            • The interesting thing about the rift eruptions is just how regular they have been. I can say with a lot of confidence that there is a high likelihood we’ll see another fissure eruption some time in the next 50 years. For how “big” of an event they are, that’s fairly astounding to me.

              I know iceland is awesome at mitigation, but just out of curiousity, have they actually done any mitigation plans for laki-style events? Or do they mostly plan for eruptions such as Krafla & Hekla?

            • Be welcome Carl & Others. Bring some beer!
              Cbus: I do not think we need do that much migitation, maybe 5000 to 10000 per day. At worst may be a call up for an USN carrier or assault ship, for ferry transport of several tenths of thusand elderly or patiants. Might be worse if flu hit us same time. I do not think we had eight month long eruption since 1947. Then nobody left. Well, I lie. US Army at Keflavik left!
              (Officially it did, the cooks remained!)

            • Provided we still have any. At the rate they are going we will be without a deployable carrier pretty soon.

            • How to interpret what I stated. In a normal mode fault, the two sides move apart. That means the max displacement points at how wide the crack opens. The down dip rupture width indicates how far down into the crust the fault plane extends… and how far upwards towards the surface. I didn’t write Wells-Coppersmith, but that is the way I understand their paper.

              If we do get a quake that opens a magma resivoir to the atmosphere, my guess is that we will se some initial degassing, and how it evolves from that will depend on what is actually down there. Could be graboids, could be lemmings. Might even be Vladimir riding a SandWorm, after all, he’s ridden everything but Justin Beiber for a photo Op. Given Vlad’s recent activity, Justin better stock up on AstroGlide.

              Caveat: I’m not a geologist, and only occasionally can make a palatable plate of food. Your mileage may vary, objects in mirror are closer than they appear.

  13. Oh nice discussions.
    On Vatnafjöll being second only after Veidivotn. Yes. It makes all sense. If you continue the Veidivotn fissure further southwest and you will find Vatnafjöll and Tindfjalljokull. More or less that area is a continuation of the Veidivotn region, when followed further southwest.

    The awakening of Vatnafjöll has been going on for quite some time. It’s not a new process. There have been small eruptions east of Hekla on the past, not sure whether they were Hekla, or Vatnafjöll, or a sort of in between. One example was Raudubjallar in 1554. The fissures opened in between. If you see the map, or hike there, you see the existence of these fissures parallel to Hekla and Vatnafjöll, and between both of them.

    It’s good time to revisit Carl’s excellent article on Hekla and Vatnafjöll, two years ago.
    https://volcanocafe.wordpress.com/2012/01/10/deconstructing-hekla-hells-gate-revisited/

    Not saying that it will. But I think it is possible to see an eruption at Vatnafjöll in the nearer future. And it could be our black swan event for the hotspot cycle peak (due next couple of decades) / next large rifting event in Iceland.

    As Geolurking said, the foreshocks of the event will point how large the displacement is. If we see just a few M3 appearing in Vatnafjöll, then I reckon that it could foretell a small size fissure event like Krafla in the seventies (or like Raudubjallar)

    If it’s a few M5, then we will have something similar to Laki in scale.

    Lest not the least, the area can also have a M3 to M5 tectonic event, without an eruption. If my memory does not fail, I think the region had some larger tectonic quake in the past centuries.

    Going back to Carl’s article in 2012 on Hekla: it is interesting to note that both Hekla and Vatnafjöll share same magma, except for Hekla’s first stage (the explosive stage). It’s like that region magma is one single type/ source, but under Hekla it suffers some transformation that produces that first different magma and that first explosive stage.

    I also like to remember that Hekla’s not a volcano, rather a fissure. Vatnafjöll is not a central volcano either, but rather a fissure.

    We might be seeing a shift in behavior in the region. Hekla has done this shift in behavior in the past, alternating with Vatnafjöll. Since its birth, Hekla, for first time ever, erupts now 4 times in a century, with small sized eruptions. Recently, the asseismic volcano starts to become seismic. I wouldn’t be surprised that magma would erupt at Vatnafjöll this time. Many signs seem to point that, once again, the rules of the Hekla game seem to have changed.

    • Just one addendum, 1987 M5.8 earthquake that was actually an intrusion. As such it is the largest magmatic earthquake recorded on Iceland. Epicenter was exactly where the swarm was today. After the 1987 earthquake Vatnafjöll has suffered about 1 earthquake every ten days.

    • Water injection at Hengill mostly. But then you had a swarm at Icelands second largest erupter (Vatnafjöll) two at Hekla, and possible one on the Laki fissure, but the last one is very very vague.

  14. Thank you Agimarc. Stunning photos. Highly educational content. All adds up to a brilliant post. I must reread as I couldn’t adsorb everything at one sitting. Aren’t we lucky to have so many excellent contributors to VC?
    Watching Hekla but need my bed. She will no doubt wait until I am snoring away before she does her thing 😀 But certainly I have never seen so much activity round her in so short a time span.
    My thanks to the “Locals” for their comments. Islander and irpsit I read your comments with great interest.

    • It’s okay… I wound up making Enchiladas.

      I was going to just make up some refried beans and jalapeños for my tortilla chips, kick back and drink a beer while I ponder the annual tax rape… but got carried away and wound up trying to duplicate my wife’s attempt at them from a few days ago.

      Now it’s raining it’s ass off and there is a small furry dog trying to occupy my lap due to the thunder. Yee Haw. I’ll have my beer yet, mark my words.

  15. I’m wondering what the IMO is thinking of this activity. Not mentioned much but Husavik also seems to be have the not so occasional earthquakes as well.

  16. Thanks for a wonderful post. I love reading about the volcanoes in Alaska. You also find great photos.

  17. I have a friend who is taking a biking excursion to Anchorage. They are shipping their bikes to Washington State and will be riding the rest of the way. The scenery, yeah, I am so friken envious… but a bike? No farking way. I’ve seen too much bad stuff related to motorcycles. Even had to help EMS remove teeth from telephone poles. Not for me. Period.

    I have mentioned to him just how special that countryside is and have pointed him at this article.

    If Birgit has a location in mind, I may be able to talk Izzy into gathering a soil sample that could contain a dusting of ash from one of the volcanoes…. but I need a recommendation of a likely site where he can drive a 4″ to 6″ tube into the ground for retrieval. Climbing a peak is out of the question. He’s gonna be on holiday and not dragging hiking equipment with him.

    Stay safe on your trip Izzy!

    • I misread that, first time around I’m sure the sentence stared “I have fried a bikini” I guess I need some morning coffee 🙂

      • Heh…. interesting concept. My Daughter has fried IN her bikini, but not fried A bikini. She had this aloe vera based ointment that was da bomb! Years ago, when I used to bicycle quite regularly, I have on occasion bar-b-qued my shoulders. That stuff works great. Never peeled after using that. Having grown up in the vicious sun of central Mississippi, I have a lot of experience with sunburn. That stuff was a God send! I don’t bike like I should, but have resorted to SPF-50 before I go out for extended periods. Nowdays I don’t get any where near the sun that I should during summer, but I feel that it helps me maintain my perky girlish pale skin. :D. (I actually don’t really like the bright sun, though I don’t hiss at it. But if I had my druthers, the dark of night is my preference. It was always a magical time when I was growing up. The bad part is when the sun is coming up and your body realizes just how much sleep you have missed. It’s quite depressing then.)

        In all truthfulness, I occasionally wind up with one tan arm…. the one on the left, due to the sun and the window. It looks pretty freaking weird when it happens.

        • “If I had my druthers”
          Oh Lurking! I have never heard that expression before. I love it! druthers….. I googled it…

          Druthers, as opposed to its earlier variant drathers, is traced back to 1876 in Dialect Notes:
          “Bein’s I caint have my druthers an’ set still, I cal’late I’d better pearten up an’ go ‘long.”

          I love dialect 🙂

          • Well, one thing that irritates me to no end are the poser politicians who feebly try to adopt a regional dialect while campaigning. One of the more recent examples occurred up in Selma Alabama as a group of them tried to curry favor with the crowd by faking what they believed to be a southern dialect.

            Following one of the Ansei Great Earthquakes, local residents used dialect as a way of identifying Koreans who were then beset with violence due to the belief that they were the cause of the misfortune following the quake.

            If you want a short excursion into dialect, try this:

            • My wife and I having Appalachian roots can tell a Deep Southern accent from an Appalachian. say,Atalanta Ga. Vs. Gatlinburg Ky. Wife is a retired English teacher so she is fascinated by dialect too..

    • As Carl has noted…. likely the release of existing stress at a lower energy rate. 50 Mag 5.2 quakes is easier to deal with than one Mag 7.0.

      My guess is the anti frack crowd who is dragging around their tired old agenda of eliminating ready access to energy is behind the study, along with self serving lawyers who need a fresh teat to feed off of.

      Directly, the energy put into a fracking operation is far out sized by the energy release of the quake. That glaring disparity should easily point out that there was a release of stress that was already present…. waiting until enough had built up to snap a fault. It was going to be released eventually, and likely at a much higher level.

      How come you never see that crowd screaming bloody murder about injection at hydrothermal plants? Hengill is always having injection related swarms. The same thing happens at The Geysers, California… with nary a peep.

      The cold hard fact is that fracking for natural gas has lessened pollution since it burns cleaner than coal. You would think that would be a good thing for the “we know all” crowd. No, lets just start a regional conflict in Syria and Crimea that could end in total war since the Nimby’s want the extraction to happen somewhere else so they don’t have to look at it or face the fact that their demand for energy is what drives the whole process.

      Personally, I like not freezing my ass off.

        • True. But my point still stands.

          The last time I experienced anything that cold I was slinging boxes of frozen meat into neat little stacks. At least then I could step outside and have a break from the meat locker. Why we were using grade “D” beef is beyond me.

          • BTW, that grade “D” beef was for the mess hall at Service School Command up in Great Lakes… about 30 years ago while I was in holding company waiting for my school to class up. Colder that shit (in the meat locker), but it beat dangling in a window painting at the boat house…. though the guy who worked there were much easier to get along with… mostly a few Boatswain’s mates and a couple of Enginemen who were assigned there for their shore duty.

  18. British Pathé has uploaded its 80.000 clips archive to youtube, amongst a bunch of historic volcano videos, e.g. “Volcano Hits Congo – Nyamuragira Volcano Erupts (1952)”

      • Had an old Flight instructor that was there in the US Army Air force when that happened. He’d spent time in Alaska and knew better than to fly trough
        the ash cloud. some didn’t and of course zorched the engines of their B-25.
        no fatalities couple of bailouts though..

  19. i remember driving the Alcan (Alaska/Canada) hwy in the 60’s. The road goes west and then gently turning south wards towards Anchorage. It took FOREVER to drive past these looming giants. i thought we’d driven thu a worm hole in the universe and were now somewhere stuck forever. Because of the gentle turn of the road and the high summer sun i couldn’t get a feel of making progress past them. Very Weird. And i may have mentioned before; during the large 7.9 i was on the phone to Son in Fairbanks. i could hear the earthquake shaking his house thu the phone and quickly had Daughter call other Son in Anchorage and told him quake was coming. Also called in grandchildren playing in yard and told them to hang on as quake was coming. We all experienced the quake together. Shaking stopped in Fairbanks first and we could enjoy the rest as we were sure it would eventually stop. my house shook and rung chimes hanging from ceiling. Grandkids thought mots was pretty cool to be able to predict earthquake. 😉 Best!motsfo

  20. PUBLIC WARNING!!!

    There is a bogus news from a bogus news-source recounting an equaly bogus Russian authority issuing an eruption allert for a volcano in Idaho. Problem is that it is not a volcano, it is an alpine style faulting pushing a mountain upwards. Borah Peak is not going to erupt since it can’t erupt at all…

    Here is a link if anyone would like to read some Grade A Dung!
    http://www.eutimes.net/2014/04/volcanic-red-alert-issued-for-idaho-by-emercom-scientists/

    • It’s Challis being Challis -happens. great place for mines,etc. not good for sleep.
      been there. Almost like living in Iceland 😉
      BTW Iceland’s winters are milder.;-)

    • One other thing the article relates this to Fracking? Gazprom is scared that their gas business is shriveling-and are one of the biggest drivers along with OPEC against it..
      Been in that central Idaho Country a lot over the years… NO shale gas or oil btw..

      • I guess it’s quid pro quo. Our meddlers stir up shit in Crimea, motivating unrest with people via the social networks “sheep control” mechanism and then when it gets messy they step up the rhetoric and try to paint Pootie Poot in a bad light.

        As much as I hate to say it, I have to give proffs to Pootie Poot for not putting up with any of the poser smack talk.

        And when we are actually asked for help we send MRE’s?
        Who are they gonna be able to stop with aged pancakes? It would have made more sense for the admin to send those “Fast and Furious” weapons that they provided to the Mexican drug gangs to Ukraine instead. I guess Ukraine doesn’t give money to the right politicians.

  21. Yay! I’m filed! And I don’t have to give them both my kidneys! Woot!

    For you dialect jugglers…

    Principally raised in Louisiana before moving to Alabama.
    August 8, 1975 does a faceplant off of Ajax Peak in Montana which nearly killed him. Due to the scars from them putting him back together, he began wearing the beard and shades.

    And another… this one was raised in Jacksonville Fl.

    Edit: Replaced the cheap arsed modern imitation of Lynyrd Skynyrd with the real thing.

    And… a classic by Texan Waylon Jennings → Waymore’s Blues

    And something I have been amused with for about a week, a rendition of “Emigrants Song” by Led Zepplin where Robert Plant pronounces it “Vallhaler” instead of Valhalla. Being English you would think that this wouldn’t happen… but it was after they had hit it big, and he was mired in the morass of US culture and linguistics.

  22. An off the wall question… anyone have any idea what the OWL is? It is a Geographical, seismic, and potentially volcanic feature in Washington, Oregon, and at least part of Idaho.

    Summary: What we know about the OWL

    First reported by Erwin Raisz in 1945.
    Seems to have more depressions and basins on the north side.
    Associated with many right-lateral strike-slip fault zones.
    Seems to be expressed in Quaternary (recent) glacial deposits.
    Does not offset Columbia River Basalts, so older than 17 million years.
    Not offset by the Straight Creek Fault, so probably younger than 41 million years. (Maybe.)
    Approximately separates oceanic-continental provinces.
    Not an oceanic-continental crustal boundary. (Maybe.)
    Not a hotspot track. (Maybe.)
    Seems to be aligned with lithospheric flow from the Juan de Fuca Ridge.
    Seems to be faint and confused in Oregon.

    • One take on the OWL is that it is a remnant of an old basin structure and could be an archaic sheer zone.

      Problem with the OWL, it is manifest in such a wide range of topological ages, yet nothing has identified an existing fault or definable structure.

      The OWL is an enigma. It’s there but it shouldn’t really be there.

      Hey Dude… You’re BUSTED!

      I really hope that the actual groom is to her right and she is just curious about what the best man is up to with her sister.

  23. In regards of the fake Russian warning of an “impending eruption in Idaho” I would like to convey what Dr Peter Webley wrote over on our FB page.

    “As WOVO representative for Americas and Caribbean and one of co chairs I can confirm that USGS would be official observatory for any US volcano. Also in Russia, only agencies that provide any alert status as KVERT and SVERT and they do this for their areas of responsibility in Kamchatka and Sakhalins respectively. So this is not any official information on status of these volcanoes.”

    And with that laying down of the law we can put Idaho to volcanic rest 😉

    • I am used to the frequent “Russian scientists say this… and that….” total BS. I’m waiting for the day when these same “experts” start working on Yellowstone theories and predictions (if they have not already). 😀
      By their current logic, I should also expect the Alpine range to erupt soon in a Laki fissure style. 😀

      • I think we should separate Russian “scientists” from the Russian Scientis at Kvert and Svert. The latter bunch really know what they are talking about, and if one of them would say something I would listen. But, they would not issue a warning for the US. If one of them found something odd in a US volcano they would just call the ones in charge of that particular US volcano and ask them what is up. And here is the thing, volcanologists are inordinately proud of “their” volcano and love to tell the world about their particular volcanoes antics. 🙂

        “I have a bigger volcano than you!” seems to be a common thing among Volcanologists. (Now ducking from Peter and Boris)

        • Yeah, those Kamchatka guys really do have their shit in one sock. Many accolades to them.

          Colloquialism: They really know what they are doing and are highly competent.

    • “we can put Idaho to volcanic rest ”

      Awww…. and I just picked up sour creme and bacon bits… Idaho has some of the best bakers.

  24. THIS IS A CROSS POST From the tail of the next topic, brought here for continuity since it applies here.

    These are some of the formative structures that make up the Wrangellia Terrane. As you can see, not all of the volcanoes there are native. Some are plastered in place from a previous volcanic island chain. Think of them as “pre-fab” volcanoes.


    Image Source Wikimedia Commons

    Intermontane Trench, Intermontane Islands, and Slide Mountain Ocean


    Image Source Wikimedia Commons
    … like bugs on a windshield…

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