Alaska's Mt. Iliamna Volcano Rumbles Away

The heightened seismicity at Alaska's mt. Iliamna continues, and today the seismicity is stronger than it has been. At around 6am UTC seismicity increased and is ongoing at this time. This probably indicates further intrusion as the seismicity does appear to be harmonic tremor. Mt. Iliamna has not erupted in historical time, but the mountain displays vigorous fumeroles at the summit and flank. A previous visit by AVO scientists revealed heightened temperatures and gas emissions from the fumeroles, but they were quick to point out that the current unrest is similar to events in the 1990's when magma dike intrusion occurred, but did not lead to an eruption.

Live webicorder of Iliamna seismicity from AVO.

However the current unrest at the volcano is strong compared to previous events, and has now been underway for well over a month or so. It is my guess that intrusion is definitely taking place. Whether or not this actually leads to an eruption remains to be seen, but all the indicators are there.

Live image via AVO webcam of Mt. Iliamna

An eruption at Iliamna would most likely start off explosive, most likely phreatic eruptions. Phreatic eruptions occur when melt water comes into contact with a subterranean heat source like a magma chamber or very hot rock. This results in water flashing into steam and creating a steam driven explosion. Once this occurs, it can release pressure holding back the magma, and would likely enter a dome building phase. Of course, this is speculation because we've never seen the volcano erupt in historical time, and the structure of the volcano is highly eroded by glaciation.

Currently the visual indicators from Iliamna (via webcam) show nothing unusual, but as is the case for volcanoes that haven't recently erupted, this can change suddenly at any time. Eyjafjallajökull in Iceland experienced a couple hundred years of dormancy until seismicity increased, and began with a small fissure eruption, and then a main event that caused a widespread ash cloud to strand passengers in Europe for weeks on end, causing economic hardship in the Eurozone, not to mention a lot of frustration.

Due to Iliamna's location on a heavily trafficked air route, an eruption would cause some travel disruptions if an ash cloud was produced. However, there is no threat to any human population due to its remoteness but ashfall would likely occur in some towns near the area (including the area where the webcam is placed!). Alaskans are no stranger to ash covered homes and cars, as two volcanoes, Cleveland and Augustine frequently erupt and produce fine ash.

As it stands right now, there is no imminent risk of eruption, just heightened temperature and seismicity. You would likely see a much more dramatic rise in harmonic tremor and larger, more frequent, and shallower quakes if the eruption was about to start or was underway. But the best indicator of all, of course, is the webcam and visual observations. Until then, Iliamna rumbles away, keeping us all guessing.

AVO Lowers Alert For Cleveland Volcano To "Yellow"

The slowly erupting stratovolcano in Alaska, Mt. Cleveland, has been lowered to level "Yellow/Advisory" with AVO geologists stating "No further explosions have been detected at Cleveland since March 13, and we have no evidence that lava-dome growth has renewed since then. Therefore, we are lowering the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY."

Mt. Cleveland had been experiencing slow lava dome growth for the better part of a year, with a couple of collapses and small explosions, but nothing in the range of some of its past activities. Cleveland volcano has in the past erupted quite violently creating large plumes of ash some 30,000 feet high, but this episode was slow, effusive, and really not a huge deal.

The island itself is uninhabited, and far from any populated areas. It is however the only volcano of the Aleutian arc with a fatality (one) on its record, from an eruption in 1944. Mostly the volcano has annoyingly deposited ash  on nearby towns during large eruptions, or caused air traffic diversions.

The other volcano showing signs of unrest in Alaska is Mt. Iliamna which has undergone a series of magmatic quakes, thought to be related to dike intrusion. A recent expedition by AVO scientists to this volcano has revealed an increase in gas emissions (SO2, and CO2), and vigorous steaming/fumerole action. AVOstates that this does not mean an eruption is imminent and they saw no signs of rockfall, or avalanches in the area. However, they did seem to note some slight deformation in a glacier, but they were unable to attribute that solely to the volcano.

AVO Sends Team To Mt. Iliamna To Check Gas/Temps [UPDATED]

AVO scientists have sent a team of geologists on a fly-by mission to Mt. Iliamna, Alaska's restive volcano that has been showing signs of activity since January. The apparently successful mission to go to the volcano to check gas levels and temperatures on the summit fumeroles has produced results, and AVO is expected to release their findings today on their website (http://avo.alaska.edu).

Mt. Iliamna has been experiencing heightened levels of seismicity for some time, but recently in January there were some rather intense quake swarms, at very shallow depths (some swarms were less than 1km underneath the surface), with some quakes registering up to magnitude 3.7. AVO has subsequently raised the alert level to "Yellow"(watch), and has actually directed one of their webcams to watch the volcano visually (below picture).

Live webcam snapshot from AVO.alaska.edu

Iliamna does not have a record of historical eruptions, however AVO and GVP state that it's last eruption was approximately 140-200 years ago. Active fumeroles exist at the summit, and the last activity in 1996 was similar to the current level of activity.The 1996 quake swarms were also thought to be magma dike intrusion, much like today's swarms. AVO scientists stress that this does NOT mean there will be an eruption, however I would wager that with several dike intrusions, the magma will try to find some way to the surface. In my opinion, a minor eruption is very likely at Iliamna in the coming months or years.

It is anyone's guess as to what characteristics an eruption at Iliamna would take on. It is a stratovolcano, and part of a subduction zone, so like most Aleutian and Alaskan volcanoes, it would likely be an explosive event followed by dome growth and thick lava effusion. For now, AVO is monitoring the volcano, and so am I!

*****UPDATE 3/20/2012*****

AVO has completed their initial survey of Iliamna volcano and released the following news:

"Seismicity at Iliamna Volcano remains above background. Data from Saturday's gas and observation flight indicate that the volcano is emitting elevated levels of sulfur dioxide and carbon dioxide, consistent with a magmatic source. It is not know, however, if this is a newly intruded magma, or whether new pathways for gas from preexisting magma have caused the increased gas flux. The amount of gas being emitted is broadly similar to levels seen in 1996-1997, when a likely magmatic intrusion but no eruption occurred at the volcano.

Observers on the flight saw vigorous and plentiful fumaroles (gas vents) at the volcano's summit, consistent with the elevated gas emissions. No obvious signs of recent rockfall, large areas of newly exposed bedrock, or unusual disturbance of the glacial ice were observed. Some deformation of the ice at the headwall of the Red Glacier on the east side of the summit was seen, but it is not clear this is related to the current volcanic unrest; avalanching of the glacier is common on this very steep area and was last seen in 2008."

So it does appear at this time that activity has at least increased visually, indicating rising temperatures from deep below. Iliamna is officially a volcano to keep an eye on!

Alaska's Cleveland Volcano Has An Explosion, Iliamna Rumbles Away

Alaska's volcanic activity is picking up. Mount Cleveland was reported by multiple news sources and AVO as having had an explosive event on Wednesday, although the cloud is reported to be far less in height than the 20,000 meters it would take to institute a no-fly zone. AVO stated "A small, short duration explosion was detected from Cleveland Volcano on distant seismic stations and infrasound arrays. The time of the explosion was approximately 4:05 UTC March 8 (7:05 PM March 7, AKST.) Weather cloud conditions prevented the detection of an eruption cloud in satellite images or visual observation of the summit. This explosion was similar to recent small events that occurred in December 2011 and produced small ash clouds that dissipated quickly and did not affect air traffic. At this time, no further activity has been detected."

And as Cleveland volcano slowly plods along with what seems to be akin to a slow motion, low explosive eruption, a volcano I have mentioned in a previous post, Iliamna, is showing more signs of dike intrusion. Heightened seismicity including very shallow quakes under the restive volcano, which has no recorded history of eruptions during human habitation in Alaska, is causing AVO to suspect what I have said in the past, that Iliamna is waking up, and is preparing to erupt. The last radiocarbon dates for any eruption at Illiamna are thought to be 140-300 years ago. A record number of seismic events (for Illiamna) is occurring, and AVO scientists are planning a fly by to check for any visual signs of a change in activity. They will be checking for steaming, fumeroles, melting ice, etc.

Today alone, Illiamna has had over 40 quakes, some of them not-so-small, with the largest being a 3.2 magnitude beneath the summit, at a depth of only 2.0km, closely followed by a 3.1 quake at a shallower depth of 1.2km. It is my humble opinion that Illiamna is indeed ready to erupt, and this will occur either this month, or this year. We will wait and see, but so far I have been right about this volcano, and as far as I know, I was the first to report on its unrest aside from AVO noticing the tremor waves (I could not find anything or any other news that was posted before this article). Maybe I'm on to something!

Current seismic tremor at Iliamna Volcano, from AVO website.

In any case, the amount of quakes today alone make me almost think an eruption is already occurring. If it isn't it certainly might very soon, and we have very little idea as to how this volcano will erupt, given that it has never been witnessed in eruption (the only info we have is forensic). The picture below shows the current (last 24 hours) swarm of quakes, while the quakes in Yellow have occurred within the week. 

Image from Google Earth with USGS real-time quake overlay.

Iliamna is a stratovolcano, common for the US's Pacific Ring Of Fire volcanoes, and is most likely capable, like most of its neighbors, of large explosive events. An eruption at Iliamna will most likely cause some disruption to air travel, as well as ashfall on nearby towns, however the immediate area surrounding the volcano is not populated by any permanent towns. This volcano will likely not be able to directly kill anyone, thankfully. Time will tell on this, but it is looking more and more like an eruption at Iliamna is imminent.

As of now, AVO has NOT raised the alert level for Iliamna, however if I were them I would at least consider at this point raising the alert level to "Yellow" (watch). It would be a tragedy if this volcano were to erupt as an airplane is flying over, much like the incident in the 1980's when Mount Redoubt suddenly blew and nearly caused a fatal crash.

The Smithsonian GVP says this about Iliamna:

"Iliamna is a prominent, 3053-m-high glacier-covered stratovolcano in Lake Clark National Park on the western side of Cook Inlet, about 225 km SW of Anchorage. Its flat-topped summit is flanked on the south, along a 5-km-long ridge, by the prominent North and South Twin Peaks, satellitic lava dome complexes. The Johnson Glacier dome complex lies on the NE flank. Steep headwalls on the southern and eastern flanks expose an inaccessible cross-section of the volcano. Major glaciers radiate from the summit, and valleys below the summit contain debris-avalanche and lahar deposits. Only a few major Holocene explosive eruptions have occurred from the deeply dissected volcano, which lacks a distinct crater. Most of the reports of historical eruptions may represent plumes from vigorous fumaroles east and SE of the summit, which are often mistaken for eruption columns (Miller et al., 1998). Eruptions producing pyroclastic flows have been dated at as recent as about 300 and 140 years ago (into the historical period), and elevated seismicity accompanying dike emplacement beneath the volcano was recorded in 1996."

I will probably post an entirely separate article should Iliamna decide to erupt.

*****UPDATE 3/11/2012*****

AVO has raised the alert level at Iliamna to Yellow. They posted the following statement:

"Over the past three months the earthquake rate at Iliamna Volcano has steadily increased and now exceeds normal background levels. Although it is not certain that this sustained increase in earthquake activity represents the movement of magma at depth, it is a significant change and AVO has increased the Alert Level to Advisory and the Aviation Color Code to Yellow. The current activity does not mean an eruption is imminent or certain. A similarly energetic episode of seismic unrest from September 1996 to February 1997 was likely related to the intrusion of new magma at depth, but an eruption did not occur."

Alaska's Mount Iliamna May Be Erupting

Indications from USGS seismographs, and the corresponding Google Earth Plugin suggest that an eruption is either about to take place at Iliamna volcano in Alaska, or is already occurring. Earthquake plots from the last week until now seem to indicate rising and frequent tremor, with apparent explosions on the seismographs.

Iliamna is not near any population center, and Alaska is currently experiencing extremely cold weather (down to -48 C) which would hinder anyone or anything from making good direct observations of this remote volcano. It is probable that no observation via satellite, eyewitness, or airplane will be available for some time due to the harsh weather cycle this year. It is highly unlikely that during this period any visual observations could be made except by aircraft seeing an ash plume, which may or may not occur.

Below is a screenshot from Google Earth, with the USGS Real Time Overlay, where you can see quakes within a week (most magnitude 1.1-2.8) in yellow, and the more recent (and larger, up to mag 3.0) coded in orange, denoting a quake in the last 24 hours. These all occur at relatively shallow depths, and are directly beneath the summit, and along the flanks at lower depths. This indicates a rise in magma, and a possible eruption. These signals and the depths at which they are occurring can only mean magma intrusion, as this is a subduction zone, and most non volcanic quakes in the region happen at a much deeper depth (around 210km), not less than 1km. Subduction zones create an exteme amount of energy which heats the rock and creates magma plumes. The volcanoes of the Aleutian arc are very similar to the volcanoes of the Cascades and Indonesia in this respect.

AVO has stated "Since the middle of January 2012 there have been a sequence of earthquakes with several greater than magnitude 2. It is common to have earthquake swarms in the vicinity of Iliamna and the ongoing activity is being closely monitored by AVO seismologists.". They are aware of the current seismicity.

Image from Google Earth with USGS overlay. You can see the localization of the quakes here.

The seismographs from AVO seem to also indicate activity at the volcano. If it has not erupted already, there has CERTAINLY been a large intrusion of magma into its chamber, and will erupt soon.


                                     

Image of AVO seismograph for the last 24 hours. Clearly indicating possible dike intrusion.

Keep your eyes on Iliamna volcano. Especially the AVO seismographs. Unfortunately, this volcano does not have an active webcam to go with the seismograph, and people are very unlikely to be mounting an expedition to this volcano during the inclement weather that Alaska is experiencing right now. Indeed, the only report aside from this one (AVO would never speculate on their volcanoes without proof after all) would be from pilots. So for now, I'll say this. I absolutely suspect an eruption is either taking place at Iliamna currently (or already has), or it will happen very soon.

If there are any updates to this from any official source, I will update this post.

*****UPDATE*****

It appears via seismograph that constant harmonic tremor is now taking place at Iliamna volcano (see above seismograph image). After several large 3.0+ earthquakes, it does appear Iliamna may be erupting, or that there is further magma intrusion into the volcano. If AVO confirms this, it will be the first eruption of Iliamna since the 1950's.