Tuesday, September 25, 2012

Minor Quake Swarm At Lassen Volcanic National Park

A series of (up to now) 8 quakes has struck Lassen Peak, near Lake Helen at the South end of the mountain range. This is most likely tectonic, but the depths of all quakes were fairly consistent, consistent with a possible minor dike intrusion. USGS reports will likely indicate that this is normal background seismicity for the volcano, which has not had an eruption since 1914-1921.

The ongoing (I am at this point NOT going to call it a swarm, but it could become one if seismicity increases) activity at Lassen is at this time probably not volcanic as I stated earlier, however, the possibility does remain as this is one of the only Cascades range volcanoes aside from Mt Shasta, and Mt St Helens that have experienced any activity in the last century, or in historical (colonial) times. Cascade range volcanoes that have had eruptive activity in the last several centuries include Shasta, Hood, and Baker, but these volcanoes show very little seismicity that is of concern to anyone.

This is probably an event of crustal adjustment. However it is always wise to keep an eye on any Cascade range volcano and its quakes, as most of the range is situated near highly populated areas. An eruption from any Cascade range volcano can and does cause a lot of damage when they blow.

The last Cascade range volcano, after Lassen, to erupt was Mt St Helens in 1980.

Saturday, September 22, 2012

Blog Changes

Apparently, Google/Blogger in their infinite wisdom has decided to completely change the Blogger interface, so I am forced to learn a new system. I am sure I will grow to like it in time, but for now, I am figuring out how to deliver the same content my past posts have delivered, with an added punch.

There is not a whole lot of new volcano news right now, mostly the usual culprits, with some interesting seismicity at a couple Alaskan, Russian, and Halmaheran volcanoes, but otherwise the usual erupting volcanoes are still doing their thing. You can see the latest report at http://volcano.si.edu.

It is a bit likely that I will not post for a few days on the basis of figuring out how to use this new interface, and other added features. If anything major, or overly unusual occurs, I will certainly cover it.

For now, "Please excuse the mess, we are remodeling!".

-M

Friday, September 14, 2012

Santorini Inflating

The picturesque Greek island of Santorini is experiencing heightened seismicity, and magma chamber inflation according to an article on Live Science. The island has inflated by up to 14,000,000 cubic meters of magma, and deformation of the island has displaced outwardly from the caldera by up to 5 inches since the onset of activity last year. While it is highly unlikely that this means an eruption is imminent, the Live Science article fails to point out that hte last time Santorini was active was not the famed Minoan eruption, but last erupted in 1950, and manifested as lava dome growth and lava effusion in the center of the caldera. This formed the central island of Nea Kameni.

Inflation of the Santorini caldera is a danger, given that the last period of activity was so recent, however deflation and inflation (D/I) events occur frequently at many large volcanoes, and do not typically result in an eruption.

Santorini volcano, as is, is incapable of producing the same type of powerful eruption that ended the Minoan civilization. The caldera has already collapsed, and the most power it was capable of producing was expended millenia ago. A modern day eruption would likely be another dome building event, with possible pyroclastic flow, and lava effusion in the center of the caldera. This would pose a minor threat to the residents of Santorini, but probably not more than that.

Thursday, September 13, 2012

Fuego Volcano in Guatemala Forces Evacuations

The very frequently active stratovolcano in Guatemala, Mt Fuego (Mountain of Fire) has begun eruptions that have forced the evacuation of some 33,000 residents from nearby towns and villages. Last week a powerful explosion took place that produced minor pyroclastic flows and deposited ash on nearby towns, but today's eruption was much more powerful, producing rocketing clouds of gas and ash that forced the immediate evacuation of the surrounding area, and producing ash clouds reaching over two miles into the sky.

The volcano has not erupted with this intensity since at least 1999, a Guatemalan volcanologist stated, who is  familiar with the volcanoes history.

Fuego is one of Guatemala's most active volcanoes, and has been in near constant eruption since record keeping began when the Spanish colonized the area in 1524.

The main dangers of this volcano are from pyroclastic flows, which can reach incredible speeds on land, and even more so over water; lahars, a deadly mixture of water, ash, rock and debris that can inundate and crush entire villages off of maps; and ashfall over cities which can cause major respiratory problems for people, and animals who inhale the fine glassy shards that make up volcanic ash.

Currently, ashfall is falling about 25km from the summit, but that will likely increase if the eruption becomes more intense.

In this scenario, people would be advised to wear breathing masks. If you do not have a breathing mask, breathing through a wet cloth will do just as well, if not better. Eye protection such as swim goggles is also highly advisable, as the fine ash will also irritate the eyes to the point that you cannot see and are in a lot of pain. People should avoid being outdoors if possible, and seek higher ground if it is raining. Rain and ash are a deadly combination.

If you have supplies such as batteries, flashlights, tents, etc, you should be in good shape. No doubt the people in Guatemala are used to living next to this volcano, so I am sure they have gone through these drills before. It will be curious to watch and see if this volcano increased in intensity, or decreases in the coming weeks.


Tuesday, September 11, 2012

Light Seismicity at Eyjafjallajökull and Katla Volcanoes

2012 has been an extremely kind year volcanically to Iceland. In 2010-2011 there were a couple major eruptions, from Eyjafjallajökull and Grimsvötn (Grimsnes) volcanoes that caused some chaos for travelers, and misery for Icelanders near Eyjafjallajökull due to heavy ashfall. But while there are no volcanoes erupting (yet), Iceland remains ever restless. 

Today there were two very minor and somewhat deep earthquakes between the summit of Eyjafjallajökull, and Katla volcano, very near the vicinity of the initial fissure eruption of Fimmvörduhals. While it is not unusual for the occasional small quake to occur, especially after an eruptive period, there are several things to consider when looking at Katla and its long-winded neighbor. 

Some scientists suggest that Katla and Eyjafjallajökull share a somewhat symbiotic magma chamber (although it is speculation) in which an eruption of one volcano can trigger an eruption in the other. Katla volcano has remained mostly quiet after the Eyjafjallajökull eruption, but not silent by any means. In June of 2011, it is thought that Katla had a very minor sub-glacial eruption that resulted in a jökullhlaup (glacier outburst flood), but since it has been content to rumble away. Currently most seismic and hydrothermal activity is restricted to the Western flank of Katla.

Another notable area of seismicity is occurring on the Reykjanes peninsula on the SW portion of Iceland. The volcanic system of Brennisteinsfjöll, and Krísuvík have been experiencing frequent seismic swarms, and blogger Jon Frímann has reported some fish kill at Kleifarvatn lake between the two volcanic systems. The Askja caldera, and neighboring systems have also been experiencing persistent seismicity.

A year without volcanic activity on Iceland would likely be a welcome respite from the past few years, although several volcanoes, including Katla, are due for an eruption, more specifically, Hekla volcano, which typically erupts nearly every ten years. The last eruption of Helka occurred in 2000, which means it could potentially erupt at a moments notice (although the volcano has given no signs of unrest so far).

Iceland is part of a hotspot/spreading rift that makes it one of the most volcanically active places on the planet except for, perhaps, the big island of Hawaii, where the ongoing eruption of Kilauea volcano has been ongoing since January of 1983, and has shown no sign of slowing down. Iceland is however different in the fact that it rests on the split between the North American, and European plates, a spreading rift, which results in not only a much larger island, but a variety of different eruption types. The eruptions of the Hawaii hotspot are almost exclusively basaltic pahoehoe lavas, whereas Iceland produces a much wider variety of volcanoes, lavas and eruptions.

Thursday, September 6, 2012

Scientists Warn Further About Mt Fuji, Japan

While it was never confirmed if Mt Fuji ever had a minor eruption which resulted in the creation of a new flank crater, it is now confirmed that the recent quake activity in the area (A 9.0, 6.4, and 5.0) around Mt. Fuji has indeed increased drastically the amount of pressure in the magma chamber of the iconic Japanese volcano. The current pressure in the chamber has reached a high level of 1.6 megapascals, which Japanese scientists are quoted as saying "is not a small figure". It has been noted that many eruptions occur with a mere 0.1 megapascals of pressure in the chamber.

Steam activity, small water eruptions, and large holes that are emitting volcanic gasses are starting to occur in the vicinity, and the crater is fuming (However I have only been able to cite this from the linked Wired.com article, and have seen no real evidence of this with cameras, video, or other sources, so don't take my word for that).

This is the most activity in the area since a swarm of low-frequency quakes occurred in 2000-2001, and began after the large 9.0, and 6.4 quakes. With the current activity, it is quite evident that the earthquake has re-pressurized the magma chamber. It is quite likely that this will remain the case until more seismicity, which is highly likely in the area, occurs and puts more pressure into the system.

One scientist has gone so far to say that he expects an eruption from Fuji now within "the next three years". Another major cause for concern about the volcano is that a new 34km long fault line was discovered after the major 9.0 2011 quake, which runs directly underneath the volcano, and if destabilized, could result in partial or total collapse of Mt. Fuji.

It is my opinion that the current activity will probably not lead to an imminent eruption (scientists have to be careful with what info they put out, you don't want to cause panic, but you also don't want to be unprepared, and erring on the side of caution is what saves lives), but you will probably see a lot of hydrothermal activity, including but not limited to, minor phreatic eruptions, increased fumerole action, and possibly some deflation/inflation (DI) events. The activity at the volcano is quite similar to the type of activity now being seen at Mt. Iliamna volcano in Alaska, which also experienced a minor magma intrusion, but has merely increased its gas emissions and level of small seismicity. Iliamna has not erupted yet, but has been on AVO's 'watch' list for nearly a year now.

An eruption from Mt. Fuji today has been estimated at a damage cost of up to ¥2.5 trillion ($3.25 billion) to the Japanese economy, and could also cost over 300,000 lives. It is critical that those living near this volcano understand the dangers, and have an evacuation plan as well as supplies they can rely on in the event this does occur. The volcano, at its full fury, is capable of massive levels of destruction to the immediate area, and includes in its arsenal the potential for pyroclastic flows, landslides, lahars, phreatic eruptions, fissures, pyroclastic cinder cones, and fast flowing pahoehoe basalt lavas.

The last eruption in 1707 blasted out a large crater on the Eastern slope of Fuji, and deposited ash as far away as Tokyo. Many buildings and towns surrounding the volcano are built on the lavas and ashes of this eruption. Due to the extensive history and record keeping of Japan, most residents are quite aware of the dangers of Fuji, and typically take any evacuation order very seriously, but pyroclastic flows are a hard thing to outrun when they can reach speeds of up to 280mph, so early warning is the best possible scenario.

I will also to see if there are any other credible sources to confirm what Wired.com is claiming in regards to steaming and gas emissions (however they did not cite a source for this claim). Its actually possible that they could be using my blog as the source for this, as I was among the first sites to report the initial supposed 'emissions' from Fuji, which I was never able to confirm save one obscure report in Japanese news.

Scientists will more than likely step up their monitoring and analysis of Fuji in the mean time, and keep a close watch on its goings-on.