Stratovolcano

Yellowstone looks to be keeping everyone on their toes as we ring in 2009. The earthquake swarm reported earlier this week is continuing, with multiple events between 2-3.5 on the Richter Scale. Again, the folks monitoring the caldera - this time the Univ. of Utah - play down these events as normal for any active caldera system ... and they're very likely right. However, the media love to bring up the "supervolcano" angle and we're even getting expert opinion from (wait for it) Garrison Keillor!.  The earthquakes are just normal earthquakes so far - none of the dreaded/anticipated harmonic…
Some more information is coming out about the activity at Koryak (aka Koryaksky) in Kamchatka. Russian geologist Alexei Ozerov says that the activity at Koryak (note: the image in the article linked here appears to have nothing to do with Koryak) has started with more power than the last known eruption of the volcano in 1956. He also mentions that the volcano is already a danger to aviation in the area (as the closing of the Petropavlosvk-Kamchatsky Airport suggested). We also have some great images of the volcano, showing the vent on the side of the volcano (see above). It is hard to tell…
Sometimes I wonder if we know more about the fates of people who died in a volcanic eruption over 1800 years ago than we do about most people who died in any given eruption this year. Not that there is anything particularly wrong with that - we're fascinated by both volcanoes and Roman antiquity - but the level of detail done for the victims of Vesuvius in 79 A.D. is stunning. Considering that this blog got started (to an extent) thanks to our cultural obsession with Pompeii, I thought it fitting to post a bit about a recent report on the last moments of a family in Pompeii. Nothing really…
The latest eruption of Sourfriere was captured from space, and NASA has just released the MODIS picture of the volcano in action. The image (above and linked) was taken 2 days after the first explosion of this unanticipated and unexpected eruption - December 4. You definitely get the idea of how much of the island of Montserrat is taken up by the volcano itself (pretty much all of it). Not much else to report on Soufriere Hills beyond the update from MVO (via SI/USGS) for the end of last week: On 3, 4, and 5 December small, relatively slow moving pyroclastic flows traveled no more than 3.2…
The blasts and pyroclastic flow from earlier this week at Soufriere Hills in Montserrat were not the only show planned for the week, apparently. The volcano continues to erupt, with reports of continued ash and ballistic glowing bombs being erupted. These eruptions are the first major ones at Soufriere Hills in 6 months, but are apparently unique with no real precursors such as seismicity (well, none identified as of yet).
The lahars and mudslides near Nevado del Huila - or, in particular, the threat of more - have prompted more evacuations. Although the known death toll from the eruption and its associated lahars is still officially only in the low double digits, at least 150 people are still missing, so that may change. You can see in the photo from Belalcazar (above) that the mud inundated the town and destroyed roads and buildings easily. This is what to expect whenever lahars are generated, along with the potential for flooding afterwards due to the dewatering of the mudflows and the blockage of drainage…
I've found a few more details about the ongoing activity at Huila in Colombia, including a video report from the BBC. It seems that the eruption at Huila is a photocopy of what happened at Nevado del Ruiz in 1985 in its style: hot ash and gasses erupted from the crater melted ice/snow near the summit to create a lahar - a deadly mix of volcanic material and water that ends up like a surging flow of liquid concrete. The lahars travelled down the Rio Paez valley (see linked map - the landslide on the map is not volcanically related). Beyond the unfortunate victims caught in the mudflows, many…
  Klyuchevskoy has already had a busy year and now we have some recent photos showing a lava flow that is snaking down the side of the volcano. The website with the lava flow image has a pile of other great eruption photos of Klyuchevskoy over the last couple of years and well worth the time to look through them all - the volcano is definitely one of those classic arc volcanoes in both shape and activity.
Eruptions and earthquakes go hand-in-hand a lot of the time. It only makes sense as magma needs to move under the crust, causing movement (i.e., earthquakes). Additionally, any sort of explosions caused by the release of volatiles might cause earthquakes or even the collapse of an edifice (which in turn, shakes the earth). So, it is not surprising that the current eruption at San Cristobal in Nicaragua has produced earthquakes. The reports are relatively lacking in details, but San Cristobal is a typical Central America stratovolcano that produces frequent Strombolian style eruptions, which…
I have been out of town for the past few days, but we do have some big (and unfortunate) news from Colombia. Nevado del Huila in southwestern Colombia erupted today and the ensuing lahar (or volcaniclastic debris flow - it is hard to tell from the reports) killed at least 4 people, and possibly as many as 10*. We know that Huila has been showing signs of activity, but now it seems like it might have had real eruption, at least to the point that a lahar was produced and possible the creation of a new summit crater. Evacuations are under way and several towns have been cut off as the lahars…
Redoubt Volcano, in Alaska, is one of the more troublesome volcanoes in the state. Not only is it relatively close to population centers, but it also lies directly within the aircraft corridors above the Aleutians for planes headed to Asia and beyond. This means that USGS and AVO geologists have to be especially vigilant in watching Redoubt's every move. Currently, the volcano has been recently changed to a yellow (elevated) alert, due to increased steam/volcanic gas emissions (remember, the number one volcanic gas is water vapor) at the volcano. So far, there haven't been any reported…
Just a brief note, but today (November 13) is the 23rd anniversary of the disastrous lahar at Nevado del Ruiz in Colombia. Over 23,000 people died when a lahar, started by a relatively minor eruption of the volcano, swept down the river valleys the side of the edifice and destroyed Armero and Chinchina. The footage of rescue efforts after the lahar were devastating and heartbreaking (caution: linked video might not be for the faint of heart). Sadly, this disaster was mostly preventable as the citizens of these towns could have had at least an hour's warning to walk to higher ground, but the…
El Reventador, the composite volcano in Ecuador, has been producing explosions and ash for the last few days, so says reports from the country's  Geophysics Institute. El Reventador is only 100 km from Ecuador's capitol, Quito, and in 2002 the volcano blanketed much of the city in ash. However, the eruptions currently occurring are much smaller and limited in scope, producing ash and throwing incandescent blocks out near the vent (see above). No evacuations are currently planned. These types of eruptions are typical for El Reventador since 2002, with increased activity every few years…
One of Kamchatka's most active volcanoes is continuing to erupt. Shiveluch, in the northern part of the Kamchatka Peninsula in Russia, produced a 26,000 foot (~8,000 meter) ash column today (November 6) as the eruptions that started in 2006 persist. The reports suggest little danger to people living on the peninsula, however the ash column is causing problems with the air travel over the region (an important corridor for trans-Pacific travel).
After nearly a year and a half of little lava dome growth at Soufriere Hills in the West Indies, this past July 26th, the volcano erupted new dome material. Why do I remind us of this, you ask? Well, the Scientific Advisory Committee at Montserrat feel that the dome growth might be restarting in earnest: Since August, any new supply of lava has been minimal. Thus while there is evidence that the eighteen-month long pause in lava dome growth may be coming to an end, it has not happened yet. The most troubling event, in their minds, is the new activity at the Gages Wall vent, which means that…
Reports from Russia indicate that Klyuchevskoy, Russia's largest volcano, is erupting. It sounds like it might not be just a murmur as Alexei Ozerov from the Institute of Volcanology and Seismology of the Far Eastern branch of the Russian Academy of Sciences says the volcano is spewing ash, rock and gases. No real details on how tall the eruption column is, but the report mentions a hazard to aircraft in the area, which would suggest that the column is at least in the 3,000-5,000 meter range. Klyuchevkoy is part of the Kamchatka volcanoes in far east Russia and last saw a major eruption…
There isn't really much information in this report, but Galeras in Colombia has been put on "high alert" for a potential eruption. The volcano did emit a ~2,400 meter steam (and ash?) column today, but beyond this, it is unclear what else might be happening at the volcano. Galeras is the most active volcano in Colombia, having erupted frequently in the past decade, producing mostly ash falls, ballistic bombs and other explosive volcanic products. It is also located within a few kilometers to Popayán (see photo above of previous activity), a city of ~200,000 people, making it a potentially…
The eruption of Kasatochi was a bit of a surprise to volcanologists who study the Aleutians, to say the least. The volcano itself has been quiet for likely over 100 years, but with relatively little warning, the volcano erupted over the summer, blasting ash (and a large amount of sulfur dioxide) into the atmosphere. We finally have some images of the destruction wreaked upon the island, and from the looks of it, the island is blanketed in grey ash from the eruption(s). Biologist who have worked on the island prior to the eruption think a significant number of auklets may be buried in the ash…
If you ever want your research to be picked up by the popular press, you pretty much need to publish in the journal Science. It (along with Nature) are seen as the Premier League of scientific publication, and even though there isn't a lot of agreement on whether what gets published in these journals is the best science has to offer (or whether it is just the most flashy), it definitely gets the press' attention. Right now, there has been a lot of noise in the science press about a recent article that discusses predicting volcanic eruption. This research on Montserrat in the West Indies,…
  UPDATE 10.9.08: This photo is not from the current eruption (see the comments below), so disregard any comments I might have about the current state of activity. Contrary to some of the earlier reports, the eruption at Soputan in Indonesia might be more impressive than previously though. Pictures of the eruption (above) show a fairly healthy eruption column coming from the volcano, although it is hard to tell if the image is just an eruption column or a column with an associated column-collapse pyroclastic flow heading down the far side of the volcano (in the picture). The former would…