Stratovolcano
eklemetti | July 30, 2008
I have a few bits of news about one (of the three) volcanoes erupting in Ecuador. Reports from the Foreign and Commonwealth Office of Ecuador says the volcano is still erupting ash and there is evidence that lava is erupting from the summit vent. Not surprisingly, there is a travel ban on both Reventador and Tungurahua.
eklemetti | July 29, 2008
It seemed like events at Soufriere Hills had been heading for a dome collapse for the past few week and sure enough, part of the summit dome collapsed last night, producing pyroclastic flows that reached the ocean along with a 40,000 foot ash column. The report I received from the Montserrat Volcano Observatory offered the following details:
The collapse started at 11:27 pm local time on Monday 28th July 2008
without any precursory activity. Part of the western side of the lava
dome collapsed generating pyroclastic flows that reached Plymouth and
the sea.
There were also a few explosions…
eklemetti | July 28, 2008
Ecuador's Geophysical Institute is reporting that Reventador is currently erupting ash. Apparently, there is no threat to nearby Quito or any pipelines near the volcano. The volcano last erupted in 2007 (although the article incorrectly reports 2002) with small VEI 2 explosions and lava flows. The last major eruption was in 2002, a VEI 4 that spread ash over Quito and caused a number of fatalities. The 2002 eruption was an impressive one (see picture above), producing numerous lahars and a 17-km tall (~55,000 feet) ash column. This also makes two currently erupting volcanoes in Ecuador with…
eklemetti | July 28, 2008
After raising the alert level at Okmok Caldera in Alaska to Red over the weekend, AVO has reduced it to Orange. Reports have the volcano producing ash columns of less than 20,000 feet versus the 35,000+ foot columns earlier in the weekend. At the same time, Cleveland Volcano is continuing to issue ash from the vent and signs are still there for a lava flow. Both of these volcanoes look like they should continuing erupting into the near future.
eklemetti | July 27, 2008
There haven't been any major developments volcano-wise over the weekend, just a few updates on some current rumblings:
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Soufriere Hills (Montserrat) coughed up more ash, producing ash columns to "thousands of feet" according to reports from the MVO. The eruptions/explosions were centered at the lava dome on the summit of the volcano, Seismicity has also increased, suggesting that a larger eruption might be in the works.
Chaiten continues to worry Chilean geologists. Although the eruption seems to have reduced in intensity over the weekend, the fear of a blockage that could lead to a…
eklemetti | July 25, 2008
The Alaska Volcano Observatory is reporting that both current eruptions in the Aleutians - at Okmok Caldera and Mount Cleveland - are showing signs of a lava extruding from the vent. Thermal anomalies have been imaged at the vents of both volcanoes, although no lava has been seen thus far. Both volcanoes continues to emit ash and steam.
The news that lava is erupting isn't really shocking (it is a volcano, you know). Many times, these eruptions begin with a "throat-clearing" phase of ash and volcanic debris being erupted from the vent. If the magma is still rising after these initial…
eklemetti | July 22, 2008
Admittedly, this is only a brief report, but there are indications that Tungurahua in Ecuador might be heading into a new period of heightened activity. Over the last week or so, there has been increased seismicity, reports of "booming noises" and increased ash emissions from the volcano. Being one of the more active volcanoes in the Andes, it would be surprising if the new eruptions were very big, but instead we might expect more frequent moderate ash and pyroclastic eruptions. However, with this little information, it is hard to tell what might happen and I'll keep my eyes peeled for more…
eklemetti | July 22, 2008
There were a number of small explosive events at Soufriere Hills in Montserrat in the past few days. Small ash columns of ~5,000 feet were produced, likely caused by some degassing or interaction with water of the andesite dome at the top of the volcano. The director of the Montserrat Volcano Observatory says there is little concern for heightened activity. The volcano has been erupting off-and-on since 1995 and these eruptions are just part of the ebb-and-flow of this period of activity.
eklemetti | July 21, 2008
Just when you thought it was exciting enough in the Aleutians, word comes in that Cleveland Volcano is erupting as well. Cleveland is a very noisy volcano on Chuginadak Island, having last erupted in February (although it hasn't been updated on the GVP page). Aircraft have been warned about both eruptions in the Alaskan island chain. Along with the eruption of Okmok Caldera, the AVO has their hands full watching these volcanoes. The latest on Okmok has a 24,000 foot ash column continuing to be emitted from the new vent.
eklemetti | July 21, 2008
The latest eruption at Llaima is beginning to slow down according to Chilean state geologist, Hugo Moreno. The volcano has been erupting for most of the month, forcing limited evacuations. The eruption has (so far) produced lava flows, ash falls and some bombs thrown from the crater. However, the SERNAGEOMIN is keeping the "red alert" on Llaima.
With persistently active volcanoes like Llaima, it is not surprising that they see multiple eruptive periods during each year. In a sense, this is actually better for the people living around the volcano because the more often the volcano erupts, the…
eklemetti | July 21, 2008
I suppose this is more "unnews" than "news", but workers at Ruapehu in New Zealand report that seismicity has decreased, gas emissions have returned to background and the crater lake has cooled, indicating that the current eruptive cycle which started in September 2007 might be winding down. There was some concern earlier in the summer (well, northern hemisphere summer) that it was cranking up to erupt, but these fears seem to have abated. As always, though, Ruapehu remains on "elevated alert" for eruption.
eklemetti | July 11, 2008
Some news of a series of small eruptions at San Cristobal in Nicaragua. Ash from the small explosions drifted to a town near the volcano, however officials for Ineter in Nicaragua say that there is little chance of a large eruption.
San Cristobal is one of the seven active volcanoes in Nicaragua. It has a long record of small eruptions, with at least one every year in the 21st century (and beyond). The largest eruption in recent times was in 1999 that produced lahars and an explosive eruptions (landing us at VEI 2).
eklemetti | July 10, 2008
Just a brief note that the USGS has officially pronounced the eruption that started in 2004 at Mt. Saint Helens over. They lowered the alert level to "normal" after months with little to no signs of activity. The new dome that grew in the crater formed by the 1980 eruption is 125 million cubic yards of new material as the volcano continues to rebuild.
Here is the official USGS Press Release.
Edited 7/10/08 to add the USGS Press Release.
eklemetti | July 4, 2008[wp_caption id="" align="alignnone" width="400" caption="Anak Krakatau"][/wp_caption]
Indonesia's Volcanology and Geological Disaster Mitigation Center of the Ministry of Energy and Mineral Resources (whew, that is a mouthful) has placed Anak Krakatau on high alert for increased activity. Tourists were warned not to climb on the volcanic island in the Sunda Straits that rises from the remnants of the famous 1883 eruption of Krakatau. Anak Krakatau formed within the caldera of the ancestral volcano and have been fairly active since the 1920's, producing incandescent bombs and small ash…
eklemetti | July 4, 2008[wp_caption id="" align="alignnone" width="360" caption="Llaima 2008"][/wp_caption]
The current eruption at Llaima in Chile is causing some concern about flooding in the Rio Calbuco near the volcano. The lava flows are melting snow on the volcano and this is being exacerbated by heavy rain in the area as well. The eruption seems to have waned some according to the governor of the region. This all follows the evacuations of people near the volcano and the red alert issued by the Chilean government. (The picture of Llaima is from the January 2008 eruption.)
eklemetti | July 1, 2008
Update 7/2/08: Sounds like the lava flows from Llaima are increasing ... or that there are more of them. The lava flows, as mentioned below, pose a threat to melt the ice on the volcano and produce lahars, or at least flooding.
Lots of news this morning about a new eruption at Llaima in Chile. The composite volcano is in south central Chile (the lakes region) about 430 miles south of Santiago. This is at least the third time this year that Llaima has erupted, and this time a lava flow is heading down the volcano towards the Rio Calbuco as far as 800 m downslope. The fear is the lava flow…
eklemetti | June 29, 2008
Almost 9 months since its last eruption, Ruapehu is keeping New Zealanders guessing about its next move. Brad Scott of GNS Science (NZ) reports that the crater lake at Ruapehu is reading unusually warm temperatures and high gas emissions, well after geologists there would have expected after the last eruption. Their conclusion doesn't seem to point to an imminent eruption, but rather just "unrest" at the volcano. Ruapehu is a fairly unique situation, mitigation-wise, as the volcano is a popular tourist destination for its skiing, but is also a relatively active volcano. This means that…
eklemetti | June 24, 2008
If Alaska wants to take a cue from Iceland, it might find itself with more power than it can use. That is, if the dreams of the Alaska Division of Oil and Gas come true. They are planning to lease land on Mt. Spurr and possibly Mt. Augustine for geothermal exploration. Both of these volcanoes are active, with Mt. Spurr erupting last in 1992 (famously almost taking out a KLM 747 due to volcanic ash EDIT: Oops, this was not Spurr in 1992, but Redoubt in 1989. Luckily, AVO knew to warn aviation about the Spurr eruption thanks to the lessons learned from the near disaster at Redoubt) and…
eklemetti | June 10, 2008
One of the most famous eruptions in human history (at least recent history) is the 1883 eruption of Krakatau in Indonesia, made (more) famous by Simon Winchester's book (and the inappropriately named film Krakatoa: East of Java ... hint: look at a map). Since the cataclysm eruption, a new volcano has risen where the old one once stood. Anak Krakatau (I believe loosely translates to "son of Krakatau") is a fairly active volcano, producing Strombolian explosive eruptions - fairly mild - that threw volcanic bombs and debris onto the island and into the surrounding ocean (thus, building up the…
eklemetti | May 26, 2008
Tungurahua, one of the most active (and harder to pronounce) volcanoes in the Andes, has been experiencing explosions over the last few days. Not much in the report beyond the 125 explosions, increased seismicity and ashfall around the volcano. This is fairly typical behavior of Tungurahua: Strombolian-style eruptions (see the picture above for a great example) with ash and blocks being ejected from the crater. The volcano has been continuously erupting since 1999.