Friday, January 31, 2014

Alaska's Shishaldin Volcano Alert Status Raised To Yellow

Another volcano in Alaska is being raised to Yellow Alert status by AVO after satellite images detected heightened thermal activity, and webcam observations showed steam emissions from the summit of Shishaldin Volcano. Shishaldin is one of many Alaskan stratovolcanoes lining the Aleutian Arc. It is one of the most symmetrical cone stratovolcanoes in the world, with only a cone vent to throw of fits perfect cone shape on the NW flank.


Image of Shishaldin Volcano from the Smithsonian GVP

The last activity of Shishaldin was reported in October of 2009, when AVO declared its last eruptive event to be over. The last event was a lava dome building event that did not turn into a full scale eruption. The current activity may be another such event, but as the previously emplaced dome could be unstable, collapse and subsequent explosions/ash emissions are possible. There are no significant human populations nearby Shishaldin, and thus very little risk to human life should an eruption occur, although if a significant eruption does take place, ash emission could divert flight patterns, as is common with Alaskan volcanoes. 


Image of last dome building event at Shishaldin Volcano from AVO

Avo has reported the current activity:

"The Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY at Shishaldin Volcano based on satellite observations over the past day of increased surface temperatures in the summit crater, as well as increased emissions of steam observed yesterday in satellite and web camera images. These observations represent a departure from normal background activity at Shishaldin, but do not necessarily indicate that an eruption will occur. Similar levels of unrest were last noted during 2009, and did not result in an eruption. Shishaldin is monitored by a local seismic network, satellite data, web camera, telemetered geodetic network, and distant infrasound networks. Seismic monitoring of Shishaldin is significantly impaired due to equipment failures of seismic stations close to the volcano. We hope to be able to detect significant explosive activity (should it occur) using remaining functioning seismic stations in the region, satellite, and distant infrasound networks. AVO will continue to watch Shishaldin carefully for additional signs of increased unrest."

AVO is at this time hesitant to declare that an eruption is imminent. As always with Alaskan volcanoes (most of which are only monitored by seismographs, webcams, and satellites) it is difficult to adequately monitor them with the methods at hand, so typically AVO will wait for more direct evidence of an eruption before elevating the volcanoes alert status above Yellow (which is advisory, meaning aircraft are advised to use extra caution when approaching that airspace). But keep your eye on this volcano, as it has erupted over 20 times since record keeping began around 1824. Most eruptions have been quite minor or small (VEI 1-2), but it did have a couple of VEI 3 events in the late 1990's.


*****UPDATE 2/11/2014*****
AVO has released the following:

2014-02-11 11:02:42

"Unrest continues. Overnight, weakly elevated surface temperatures were seen satellite images. Partly clear web camera images from this morning show no activity. No anomalous seismicity observed in data from the one working station, though wind noise currently could be obscuring low levels of seismic activity."

2014-02-07 12:02:08 - Weekly Update

"Elevated unrest continues at Shishaldin. A possible volcanic cloud was observed this morning in satellite images beginning around 1545 UTC (6:45 AKST). This cloud may have resulted from a small explosive event at the volcano. The event was small enough that it was not detected by the one working seismic station near the volcano, but it appears to coincide with a signal recorded by a nearby tiltmeter. Satellite images suggest that the cloud may have reached as high as 25,000 ft asl, was ash poor, and short lived. There was no evidence of elevated surface temperatures observed in satellite data following this event, suggesting that it was primarily a gas event and very little to any hot material was produced and deposited on the flanks of the volcano. There have been no visible observations of the volcano since this event and AVO will continue to evaluate new data as it becomes available.Persistent elevated surface temperatures in the summit crater of Shishaldin have been observed during clear-weather intervals over the past week. Nothing unusual has been seen in seismicity from the nearest working station off the flanks of the volcano."

Tuesday, January 28, 2014

Iceland's Volcanoes Still Quiet

The land of Ice and Fire, it may be. But for the last few years now, it's been pretty much just Iceland. The last eruption to occur in Iceland took place after the now infamous Eyjafjallajökull eruption, from Grimsvötn (Grimsnes) volcano, which came and went without much fanfare. Since then, aside from some interesting quake activity, the restive continent has been nearly silent. So what gives?

Well, for one thing, volcanoes (contrary to popular belief) aren't on a schedule. Some very specific conditions need to occur for volcanoes to erupt. The eruption of Eyjafjallajökull in April of 2010 was preceded by around a decade of slow magma intrusion, and other volcanoes like Katla are buried under glaciers, which means it takes quite a bit of magma build up to break through the ice and produce an eruption. Katla had a suspected sub-glacial eruption after Eyjafjallajökull's Europe-stopping event, but this was inferred only due to glacial outburst flooding and chemical analysis.

Currently in Iceland, the ice is in full effect as Winter pokes along. It has been speculated that thick ice cover can suppress volcanic activity in Iceland (and maybe, perhaps, is suppressing volcanic activity in Greenland as well, although this has never been proven due to the thickness of the ice sheet), so some scientists suspect that quiet in Iceland could be due to this effect. When the ice retreats, an effect known as 'crustal rebound' is thought to occur, increasing the probability of an eruption, or at the very least, getting out of the way of an imminent one. But it has now been years since the last eruption and one can only wonder, which of these volcanoes will it be next?

Given what I am personally observing over there on seismographs, there seems to be only a couple 'likely' candidates for the near term. Askja volcano has been displaying some weak seismicity, and it is possible it had a slight ash and gas exhalation a couple years back, but this was never confirmed. Hekla volcano is always on everyone's watch list, but nothing unusual has been occurring there. That leaves really only a few more volcanoes over there that have much of a historical record of eruption, and none of them are acting particularly restless at the moment.

Hekla volcano has long been considered to be 'overdue' for a show, as it tends to be one of Iceland's most active. This volcano historically does not give a lot of warning before popping off, so it could indeed be primed for some action, and we simply wouldn't know. It is a complete waste of time with these volcanoes to actually predict WHEN they will go off, but it is certain that they will in the future. Time is the only thing that will tell. If anything, we could probably expect due to the ice cover, that the island may wait until Spring or Summer to show any activity as the ice recedes.

Icleand lies on a spreading fault, a tear in the earth's crust that is pulling the European plate away from the Atlantic plate, opening up fissures and channels for magma to rise up and become lava in an eruption. It is theorized that Iceland is part of a mantle plume system, much like Hawaii, that is positioned directly on this spreading fault, giving it a vast reservoir of magma, and possibly the largest mantle plume on Earth.

Friday, January 24, 2014

Dormant Peruvian Volcano El Misti Waking Up?

One of Peru's most well known volcanoes, El Misti, may be gearing up for some action. The Smithsonian GVP reports that El Misti has had some rather alarming seismic activity that could indicate magma intrusion at the volcano. El Misti does not have many historical eruptions under it's belt. The only confirmed one on record would be in the 15th century when it forced villagers to flee pyroclastic clouds.

The current seismic crisis is described by the GVP:

"Instituto Geofísico del Perú (IGP) reported that seismicity at El Misti increased during January, and a seismic swarm consisting of 119 volcano-tectonic events was detected during 14-15 January. Despite the increase, activity remained at a low level."

It is unclear exactly what they mean by 'activity remained at a low level', as all indications I can come across don't show any 'unusual' activity. The summit crater has nestled within it a fumerolic lava dome that displays heavy sulfur concentrations.


Image from Panoramio user 'dockx thierry' of summit lava dome and associated fumerolic activity.

An eruption of El Misti would likely include explosive eruption of the current lava dome, with associated pyroclastic flows descending its flanks (depending on which way the wind is blowing, it could descend any direction of the symmetrical volcano). There are several cities and towns in the shadow of the large stratovolcano, which could conceivably be at risk of ash fall and lava flow advancement, should the volcano enter into a more active phase.

As with all long-dormant volcanoes, only time will tell if the current seismicity will eventually result in an eruption. The majority of magma dike intrusions into volcanic systems do not immediately result in an eruption, and magma chambers can remain molten and pressurized for an indefinite amount of time. A good example of a fully primed, yet inactive volcano would be Mount Fuji (a very similar stratovolcano) in Japan. Scientists recently mentioned that Fuji's magma chamber is pressurized far higher than it was when it last erupted, leading some to suggest that only a minor earthquake along a bisecting fault line, could result in the triggering of an explosive eruption. 

Like Fuji, El Misti is a volcano on the Pacific Ring of Fire, a chain of volcanoes that spans the outline of the Pacific tectonic plate. It, like Fuji, also lies on a subduction zone, which causes eruptions to be far more explosive, rather than effusive like a hotspot volcano (Hawaii, Piton de la Fournaise, etc), possibly due to the immense amount of water and gases that accumulate on subduction generated magma.



Wednesday, January 22, 2014

Quake Activity Detected At Inskip Hill

About 20-25 miles WSW of Lassen Volcanic Center in Northern California lies a little known volcanic hill called Inskip. This is a Pleistocene volcanic cone complex which has had exactly no volcanic activity in historical time. Recently I have begun seeing some small quakes occur directly beneath it at a depth of about 3km, one of which occurred today at a magnitude of 2.2. This is probably nothing but it is always important to be vigilant when it comes to long dormant or presumably extinct volcanoes.


Location and magnitude of 2.2 quake under Inskip Hill, a presumably extinct volcano in Northern California near Lassen Volcanic National Park. 

While it is not at all probable that that these quakes of late are volcanic in nature, it is still possible. Inskip hill is not a well studied volcano. Indeed it was quite difficult to find any scientific or geologic information on the web, the only bit of info I found was at this link, where the volcano is described thusly:


"The hill is of volcanic origin and has numerous lava outcrops. It is part of a Plio-Pleistocene volcanic activity that began some miles to the east with the now vanished Mt. Maidu. From this cone issued first flows of basaltic andesite, followed by pyroxene andesite and dacite. Some 1.5 million years ago two enormous eruptions spewed forth rhyolite which covered some 180 square kilometers (70 square miles) to an average thickness of 152 meters (500 feet), followed by dacite avalanches which covered perhaps as third as great an area. The summit of Mt. Maidu collapsed, forming a caldera. Later came a series of basalt eruptions that built cinder cones with associated lava flows. Inskip Hill is one of these and dates to the mid or late Pleistocene. There are ice caves on the hill."

It is a bit puzzling as to why a well-preserved volcano such as this hasn't been more thoroughly studied, although the volcano does reside on private land, so I am assuming this is part of the reason.

For the past several weeks, I have seen some earthquakes pop off in this location, nearly directly under the summit of this volcano, or under its NE flank. While I am certain nobody is raising alarm bells over this (a magmatic intrusion would generate far more quakes, tremor, and probably GPS would detect ground swelling as CA is well monitored), it is still pretty interesting to speculate as to what could be going on down there. As some volcanoes have recently demonstrated (such as the abrupt and unexpected eruptions of Chaiten in Chile, and Nabro volcano in Eritrea), warnings are not always given when a volcanic system decides to reactivate.

Again, it is extremely doubtful that this is what is happening at Inskip, but perhaps blogging about these goings on might elicit some investigations, or perhaps some attention, by USGS (who as I recently found out, rather enjoy reading this blog!). In any case, I just thought this was an interesting opportunity to write about this very little known volcanic complex. I'm keeping my eyes peeled!

Thursday, January 16, 2014

Japanese Volcano Asosan Has Small Eruption [video]

The volcano known as Asosan, one of Japan's most active volcanoes, has had a small eruption amid a period of heightened unrest. Nestled in the center of a 14+ mile wide Pleistocene caldera, the resurgent stratovolcano has produced phreatic and magmatic eruptions periodically since its first historically recorded eruption in 553 A.D. On the 14th (after the GVP report), Volcanodiscovery.com reported a magmatic eruption, and posted the below video.



The report from the Smithsonian GVP is as follows:

"On 27 December 2013 JMA raised the Alert Level for Aso to 2 (on a scale of 1-5) because volcanic tremor amplitude had been increasing since 20 December. However, on 2 January 2014 the amplitude rapidly decreased. Sulfur dioxide emissions were 1,200 tons per day during 2-9 January and 1,500 tons on 10 January. Volcanic tremor amplitude increased between 0800 and 1900 on 12 January. At 1215 on 13 January a very small eruption from Naka-dake Crater generated a grayish white plume that rose 600 m and drifted S, producing ashfall downwind."

The Smithsonain GVP describes Asosan:

"The 24-km-wide Aso caldera was formed during four major explosive eruptions from 300,000 to 90,000 years ago. These produced voluminous pyroclastic flows that covered much of Kyushu. The last of these, the Aso-4 eruption, produced more than 600 cu km of airfall tephra and pyroclastic-flow deposits. A group of 17 central cones was constructed in the middle of the caldera, one of which, Naka-dake, is one of Japan's most active volcanoes. It was the location of Japan's first documented historical eruption in 553 AD. The Naka-dake complex has remained active throughout the Holocene. Several other cones have been active during the Holocene, including the Kometsuka scoria cone as recently as about 210 AD. Historical eruptions have largely consisted of basaltic to basaltic-andesite ash emission with periodic strombolian and phreatomagmatic activity. The summit crater of Naka-dake is accessible by toll road and cable car, and is one of Kyushu's most popular tourist destinations."

Eruptions of volcanoes in Japan and its associated island chains are common. Near the end of 2013, the volcano Nishino-shima began a submarine eruption that became a new island volcano off its coast. That volcano is still erupting, and growing the new island, which will likely be permanent, much like the 1960's eruption of Surtsey in Iceland. The volcano of Sakurajjima is also frequently active, and has many webcams on the web that you can watch.

Japan lies on the Pacific Ring of Fire, and lies on a subduction zone which has been responsible for many volcanic eruptions, large earthquakes, and tsunamis. In 2011, a 9.0 subduction quake cause massive amounts of damage, and an associated tsunami which has sparked a nuclear disaster in Fukushima which is being compared to Russia's Chernobyl disaster (although still not as severe).


Tuesday, January 7, 2014

Indonesia's Mt Sinabung Erupts 77 Times In One Day

The newly reactivated mount Sinabung in Indonesia is intensifying its eruptive phase, with more than 77 eruptions recorded in one day alone. The exclusion zone around the volcano has been increased to around 7km (3+ miles) and over 20,000 people have now been evacuated. Lava flows are now issuing from the mountain summit, and advancing at the foot of the volcano. There have been no fatalities so far, due to the advanced warnings and evacuation protocols in place. The government in Indonesia has a quite advanced volcanic monitoring system, due to the many disasters it has faced in the past.

Indonesia possesses more active volcanoes than any nation on earth, and has frequent volcanic disasters. Over 127 volcanoes in Indonesia are classified as active, with many others being classified as either dormant or extinct. However the classifications of dormant or extinct are indeed assumptions based on the last period of activity, and other factors, and should never be relied upon to determine whether or not a volcano can reactivate in the future. Volcanoes with no known eruptive activity during the Holocene have been known to erupt without warning, such as Chaiten in Chile, or Nabro volcano in Eritrea.

Sinabung was such a volcano, having had no prior confirmed activity before its reawakening in 2010.


Lava flows from the summit of Mount Sinabung on Jan 6th, 2014
The now nearly constant explosive activity has released devastating pyroclastic flows, and has covered nearby farmland in layers of heavy ash. Crops are likely to be wiped out, and any remaining livestock in the area is likely to be severely hurt by the ash, and more than likely die of complications and/or starvation.
Mount Sinabung lies directly NW of the Toba supervolcano, which, over 70,000 years ago, had a devastating eruption that nearly wiped out the human race, leaving some 10,000 surviving individuals to repopulate the human species. There is no indication that this eruption will have any effect on the Toba supervolcano, which has never had a historical eruption.

Indonesia lies directly on the rim of the Pacific Ring of Fire, a chain of volcanoes that encircles the subducting Pacific Plate. The majority of these volcanoes are stratovolcanoes, like Sinabung, which typically have explosive and effusive eruptions.

Monday, January 6, 2014

Unfortunately Named Or Impossible To Pronounce Volcanoes

One of the fun parts of 'Earth Browsing" on programs like Google Earth, is that you run across some... shall we say... unfortunately named places in the world. Some of the names of these places are downright hilarious, such as the town of "Batman" in Turkey, or places with ridiculously long names like Ambodilazanivivy in Madagascar. But truly, people who have the privilege of naming volcanoes have gotten away with a wee bit of fun, or at the very least, had no idea what some of these mountains would sound like in other languages.

The list of silly names for volcanoes is sort of long, but I'll pick the ones I consider to be the top 5 in the hilarity/strangeness category, and of course give you some info on them.

5) Kamchatka, Russia. Kamchatka is Russia's volcanic capitol, and home to the vast majority of all of its active volcanoes. The place lies on the Pacific Ring of Fire, and is host to frequent eruptions from several of its many stratovolcanoes. One of these dormant volcanoes goes by the very unfortunate name of "Taunshits".  Taunshits volcano last erupted in 550BCE, and has not had any historical eruptions, however it is likely to one day erupt again. Its summit sports a very thick andestitic lava flow reminiscent of its namesake... or at least the second syllable... oh brother....

4) Andaman Islands, India. India does not have many active volcanoes. The country itself is host to the Deccan Traps, remnants of what is thought to be ancient lava flows from the hotspot that is responsible for Reunion Island's "Piton de la Fournaise", but India itself is no longer host to any active volcanism. It does however own some island volcanoes North of Indonesia... namely an island called "Narcondum". Sounds like a mix of "narcotics" and "condom", but I'm certain it has some cultural meaning... or at least I hope. Narcondum island hosts one of India's two volcanic islands, the other being Barren Island. There have been no verified historical reports of any eruptions at Narcondum, but it does have a youthful look to it.

3) New Guinea is host to many active volcanoes, and many dormant ones. Off its North shore lies the volcanic island of "Blup Blup" (one can only guess as to why it may have been given such a silly name), which has never had any historical eruptions, although it is suspected to have erupted during the Holocene.

2) North of Grenada Island, in the Carribean chain of volcanoes which include volcanic 'superstars' such as Sofreirre Hills in Montserrat, and Montagne Pelée on the island of Martinique, is the bizarrely named "Kick 'em Jenny" submarine volcano. Again, one can only guess as to what brought a volcanologist (or whoever named this volcano) to name this volcano something that sounds like a violent suggestion, but hey, it gives us something to ponder I suppose. Kick 'Em Jenny has had many eruptions since its discovery in the 1930's, with rumbling sounds frequently audible by beach goers who dive underwater. It is a relatively new volcano, and it's last eruption was in December of 2001.

1) And the number one country with funky names for volcanoes has to go, hands down, to Iceland. Yep, we're going there with Eyjafjallajökull, a volcano with a name I'm not sure even Icelanders like to attempt to speak out loud (many opt for the shorter 'Eyja' or 'Eyjafjöll' moniker... to which I say, bully, still hard to pronounce!). Indeed, every web site, news caster, scientist, even the local Icelanders seem to have a different way to pronouncing this tongue twisting, air-travel-halting monster of a mountain. Eyjafjallajökull was the source of an eruption in 2010 that created massive ash clouds that drifted directly over Europe, causing airports to ground their air craft during the holiday season, creating travel chaos, delaying families, celebrities, students, musicians, and politicians from being able to fly. This eruption caused massive amounts of economic hardship for countries that were already experiencing the effects of the global recession. Eyjafjallajökull isn't the only tongue twisting Icelandic native however. It is also host to volcanoes with such names like "Snaefellsjökull", and "Theistareykjarbunga".

Hope you enjoyed this list! There are definitely more places and volcano names out there that will make you scratch your head, twist your tongue, or simply make you chuckle. Go find them!

Friday, January 3, 2014

AVO Upgrades Cleveland Alert To Orange

Alaska's notorious Cleveland Volcano has been upgraded from yellow alert status to orange amid recent explosions from the summit crater. The volcano has been in a state of unrest for several years and has had periods of summit crater dome growth, followed by explosions that destroy the dome, only to restart the process. Typically (during this particular unrest period), Cleveland will have a brief explosion that 'unplugs' the summit, ejecting hot ash and blocky lava, and then change to a period of very slow effusion that builds a plug or dome within the crater. After the dome reaches nearly the rim of the crater, this is when the explosions have been occurring usually.

Alaska Volcano Observatory (AVO) does not have monitoring equipment on Cleveland due to its remote location within the Aleutian Islands chain of volcanoes. They rely on satellite data for the majority of their reports, mainly from MODIS or German satellites. Some seismic signals are strong enough to be detected by other 'nearby' monitoring stations, but it is quite probable that Cleveland volcano is a bit more active than we give it credit for, having had probable explosions that have gone undocumented, or unnoticed.

Currently in Alaska, there are only two volcanoes showing activity of any kind. Veniaminof volcano has gone up and down from Yellow to orange and back to yellow several times in the past year or so, with periodic lava effusion from the summit cone.

In a typical year, at least one or two volcanoes is usually in a state of unrest or eruption, and Cleveland volcano is one of the most frequently active in the chain.

Cleveland volcano does not pose any threat to human populations, but does lay under many air travel routes, so an Orange designation means that air traffic may need to divert to other routes in order to avoid being unexpectedly caught in an ash column, as happened with the 1989 eruption of Redoubt volcano (which also had an eruption in 2009). An airline full of passengers was temporarily disabled as it flew through a column of ash some 45,000 meters in height, causing its engines to choke on volcanic ash that turned to glass within the turbine. Fortunately the plane was able to restart its engines before it would have crashed, and landed safely.

Thursday, January 2, 2014

Little Known Palena Volcanic Group In Chile Has Eruption



It appears that on Dec 22, a volcanic group in Chile may have had eruption, possibly for the first time in the historical record. The Palena Volcanic Group, which is described by the Smithsonian GVP as "The Palena volcano group consists of five cinder cones oriented along a NNE trend NE of Melimoyu volcano. The youthful volcanoes, which are named after the middle cone, are Holocene in age (Moreno 1985, pers. comm.)" has not had any confirmed historical eruptions. If this is true, it would mark the first observed activity in this chain of cinder cones.

I went to check out the location via Google Earth, and was only able to visually identify 3 obvious cinder cones, to the SW and NE of where the GVP marker was (Image below) so it is not clear exactly where this eruptive center (if an eruption is occurring) is located. The cones I was looking at look to be monogenetic in nature, heavily vegetated, but pretty fresh looking morphologically.

                                     

Screenshot of location for Palena Volcanic Group with 3 cones identified by marker pins, from Google Earth. 

If this report is true, this would mark the 2nd volcano in recent history with no known eruptions to pop off in less than a decade, after the spectacular and unexpected rhyolitic eruption of Chaiten. However, analysis from volcanodiscovery.com seems to indicate that this may not in fact be the case, as SERNAGEOMIN has failed to identify any seismic signals, or verify any eruption has actually taken place. As stated by volcanodiscovery.com regarding the image (below), while this looks like an ash/eruption plume, it could also have been a wildfire that was mistaken for an eruption. Only time will tell.



Image from Volcanodiscovery.com showing purported eruption in Palena volcanic group (photo: A Gillmore / Twitter)
Judging from the photographic evidence so far, and having lived through a multitude of wildfires here in San Diego, CA, this looks a lot more like a wildfire than it does a volcanic eruption, and indeed, a wildfire on a volcano can and has stirred up older ash from eruptions when it becomes swept up in the fierce fire-driven winds. So what we're looking at could possibly be a combination of wildfire ash, and older volcanic ash. I'll reserve judgment however until the science is in.

If this turns out to be a real eruption and not simply a coincidental wildfire on a volcano, this would be scientifically significant, especially regarding lower Andean eruptions. Recent large quakes along Chile's subduction zone ranging from 7.0-8.8 may have altered magmatic systems for some long dormant volcanoes, which is entirely possible, and could help to explain why some volcanoes in Chile remain dormant for so long, and seemingly randomly wake up.