volcanic hazards
eklemetti | September 18, 2008
Ruapehu is a noisy volcano, showing signs of eruptions on a yearly basis. It is also a potentially very hazardous volcano as it produces abundant lahars and has the capacity to generate a catastrophic lahar if the crater lake at the summit were to be breached by an eruption. This is why Ruapehu is one of the most closely watched volcanoes in the world, with all of its vitals being monitored on a daily basis. GNS Science in New Zealand is reporting that Ruapehu is headed into a new heating cycle, citing the increase in lake water temperature from 16 to 22C since August - and that seems like…
eklemetti | September 16, 2008
It is always fun to me when we discover that a volcano long considered dormant or extinct has seen activity in the recent past. I bring this up because Mount Nantai in Japan, a volcano that was considered to have last erupted over 10,000 to 20,000 years ago (if not longer) looks to have actually erupted as recently as 7,000 years ago. This might not seem like a big different to some folks, but this definitely puts the volcano in the "active" category if this date turns out to be accurate. The volcano looks to have had a number of explosive ash and pumice eruptions along with some dacite lava…
eklemetti | September 16, 2008
For those of us who track volcanoes and the hazards they present, the general consensus is that Mount Vesuvius in Italy is probably the most dangerous volcano in the world today. This is not because it is the biggest or most powerful, but because it is located on the outskirts of Naples, Italy, a city with over 2 million inhabitants (including the surrounding area). Evacuating such an area quickly and efficiently during a time of crisis might be, well, impossible. We know that Vesuvius can be destructive - just look at the fact that much of the Naples area is built on the deposits of the…
eklemetti | September 11, 2008
(Note: Yes, I am posting when I said I wouldn't, but I felt I needed to post about Colombia).
Colombian authorities are evacuating the area around Nevada del Huila after increased seismicity suggests that the volcano will erupt soon. There have been over 700 earthquakes - many of which are clearly related to moving magma - over the last week or so, indicating that Huila might be entering a new period of eruption.
One thing to note: The article I've linked to mentions an avalanche at Huila that was related to an eruption in 1994. I can't find any evidence that there was any volcanic activity…
eklemetti | September 7, 2008
I wanted to post the new MODIS image of Chaiten that caught the volcano erupting on September 3. I won't go into too much details, there are a lot of great updates over on the Volcanism Blog, but needless to say, the volcano is still very active, producing tall ash columns (you can see the ash blanket around the volcano in the image above as the plume drifts off to the northwest), earthquakes and pyroclastic flows as the dome in the caldera continues to grow. I'll be interested to see what geologists know about the eruption and volcano when the AGU meeting rolls around in December as there…
eklemetti | September 2, 2008
Whether this is a coincidence or not, I thought I'd mention a report of an earthquake near the crater of Nevado del Huila in Colombia. The earthquake is reported as a magnitude 4.6Â and at a depth of 20 km (although that is only a rough estimate), indicating that magma might be moving up the conduit system under the volcano - or that it might be just coincidental seismicity in a seismically active area. However, Huila had recently become active for the first time in 500 years, so this could be a sign of new activity to come.
eklemetti | September 2, 2008
Two volcanoes on the island of Luzon look like they might be primed for activity, at least according to PHILVOLCS, the Philippine Institute of Volcanology and Seismology. Both Mayon and Taal (above) are showing signs of increased seismicity. Only Mayon is actively steaming right now and the volcano had a mild ash eruption on August 10 as well. Officials in the Philippines have both volcanoes on Alert Level 1 (potential activity).
Taal is actually part of a bigger system that occupies a 15 by 20 km caldera. The island where most historic activity has occurred is made up of a series of…
eklemetti | August 19, 2008
I will be away from Eruptions for the next 2 weeks or so. I won't be on vacation, I will actually be out on volcanoes themselves doing some much-needed fieldwork. It is a three volcano tour, starting with a trip to Lassen Peak to get a guided view with Michael Clynne of the USGS (the world expert on the volcano, the last Cascade volcano to erupt other than Saint Helens).
Then follows a trip to Mt. Hood with Adam Kent from Oregon State (my doctoral alma mater) in Oregon to sample some of the youngest flows that are only a few hundred years old. Geologists from Oregon DOGAMI (Department of…
eklemetti | August 18, 2008
Sorry about the lack of update. Having no internet while moving will do that! I did see an email this morning that had some interesting information about the amount of sulfur dioxide emitted by Kasatochi (Alaska) during the current eruption (thanks to Simon Carn, UMBC):
"The August 7-8 eruption of Kasatochi volcano (Aleutian Islands)produced a very large stratospheric SO2 cloud - possibly the largest since the August 1991 eruption of Hudson (Chile). Preliminary SO2 mass calculations using Ozone Monitoring Instrument (OMI) data suggest a total SO2 burden of ~1.5 Tg. This figure will be…
eklemetti | August 14, 2008
This article sums up a lot of the events that led up to the Kasatochi (Alaska) eruption last week from the point of view of the biologists on the island itself right before it erupted. There are some great descriptions of the whole island shaking for 10 minutes, and they also offer some exciting new details such as this:
"Jeff Williams, a biologist for the maritime refuge, sailed by the island on the refuge boat the Tiglax and said the island has a new shape; what were steep cliffs rising from the ocean on the island's east and west sides now appear to be long, gradual slopes."
That would…
eklemetti | August 14, 2008
I'll be brief (as I'm in the middle of moving), but I did see a report that activity at Chaiten is increasing yet again. This seems like the operating mode for this volcano, with a waxing and waning of intensity, since the volcano started erupting on May 2. The latest report indicates renewed ash emissions producing an ash column that reaches ~20,000 feet (4,000 meters), with ash falling on nearby areas. There is also mention of some increased seismic activity at the Chilean caldera. The picture above shows the extent of the mobilized ash and volcanic debris that has wiped out much of the…
eklemetti | August 13, 2008
NASA posted a nice image of the ash plume from the current eruption at Kasatochi (Alaska) showing the brown/grey ash mixing with white clouds over the Pacific. Not much else to report on the eruption other than that AVOÂ reported that seismicity remained low from August 10-12.
eklemetti | August 11, 2008
We had a brief bit over the weekend that Mayon in the Philippines had a number of small explosive events (less the one minute worth of activity). However, Philvolcs (Philippine Institute of Volcanology and Seismology)Â is downplaying the idea that a major eruption is in the works. There have been a number of explosion-related seismic events and harmonic tremors, along with 12 mm of inflation on one side of the volcano (although over what time period the inflation occurred is not mentioned in the article). It appears that the Philvolcs scientists just think that magma is moving under the…
eklemetti | August 11, 2008
The current eruption at Kasatochi is causing a lot of flight cancellations for flights from Alaska to points in the continental US. The ash is swirling its way around the Aleutians along flight lanes (see above), with the ash drifting southeast over the Alaska Panhandle and could hamper air travel in Alaska and Canada for days according to the USGS (although Alaska Air says it might start flying again later today). As for the eruption itself, not much new news beyond the initial impression that the volcano went from quiet to explosively erupting to produce at 35,000 foot (~10,000 meter) ash…
eklemetti | August 10, 2008
Mayon, a volcano in the Philippines, is on watch for an eruption after experiencing small explosions. Philvolcs, (short for the Philippine Institute of Volcanology and Seismology), reports a small ash emission - ~200 feet - but they feel that there isn't an imminent threat of an eruption. Mayon is an relatively active volcano in the Philippines, last erupting in 2006 and is well known for its prototypical conical volcano shape (see above).
eklemetti | August 9, 2008
The folks up in Alaska have a lot to watch these days in the Aleutians, with three volcanoes erupting right now. Just a quick update on the current activity:
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Kasatochi: The eruption that started Thursday and produced 45,000 foot ash columns has quieted by Saturday, but there are still moderate (M=5) earthquakes being recorded near the island (above, before eruption).
Okmok: Ash from the month-long eruption is falling on islands near the caldera.
Cleveland: Activity at Cleveland has quieted to the point that no ash column was spotted on Saturday.
eklemetti | August 8, 2008
Just a quick update if you haven't been following the discussion: Kasatochi volcano in the Aleutians is now listed in "Red Alert" as it is erupting (see image above). Not many details beyond the typical description of ash columns, in this case reaching 45,000 feet, which is a pretty decent height. The Coast Guard warns of pumice rafts from the eruption, but it is hard to tell if it because they exist, or that it is just the generic warning for any eruption at sea. The two USFS biologists were evacuated before the eruption.
Edit 8/8/08: I'll add a link to the official USGS Press Release on…
eklemetti | August 7, 2008
The Okmok Caldera eruption is still going on, almost a month after it started. The latest USGS/SI Weekly Report states:Â
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Strong volcanic tremor on 2 August prompted AVO  to raise the Volcano Alert Level to Warning and the Aviation Color Code to Red. Cloudy conditions prevented satellite observations. Later that day, AVO geologists in the area reported that ash-and-steam plumes rose to minimum altitude of 6.1 km (20,000 ft) a.s.l. The seismicity decreased and the Volcano Alert Level was lowered to Watch and the Aviation Color Code was lowered to Orange. Observers in Ft. Glenn on Umnak…
eklemetti | August 7, 2008
Finally, in a very slow week for volcano news, we find a report from the Alaska Volcano Observatory about concerns of another eruption in the state. Currently, both Okmok and Cleveland are erupting, and now AVO has issued a warning about Kasatochi Volcano on the island of the same name (~100 kilometers east of Adak, roughly near 175W on the map above). The volcano is the island - more or less - and any people on the small island are being evacuated due to increased seismic activity underneath the volcano/island.
Not much is known about the eruptive activity at Kasatochi. The volcano does…
eklemetti | August 1, 2008
So, August rolls in and who would have thought in early May we'd still be talking about the Chaiten eruption with such intensity. Jorge Munoz of the SERNAGEOMIN is wondering whether the current eruptive activity and seismicity at Chaiten is a precursor to the end of the "first cycle" (as he calls it) of activity that started in May or that this is all leading up to another major explosive eruption (the "plugged volcano" scenario). The most puzzling part of the current activity is the high amount of seismicity: 105 earthquakes over the last few days, some of them up to magnitude 4. The…