caldera

Sorry about the brevity of this update, but I'm exhausted. From the Alaska Volcano Observatory (AVO): At this time, based on AVO analysis of satellite data, ash is continuing to erupt from a composite cinder and spatter cone called Cone D in the eastern portion of the 6-mile wide caldera or crater of Okmok. It appears that the eruption is very water-rich due to interaction of rising magma with very shallow groundwater and surficial water inside the caldera. We have few direct observations into the caldera and details of the current event remain unknown. The current activity differs in…
Sorry about the delay with updates, I am actually at a meeting filled with volcanologists (of all things), so updates might be a little sporadic. A lot of news today about Okmok erupting in the Aleutians. The Alaska Volcano Observatory had this to say: The eruption at Okmok continues based on high levels of seismicity and ash continues to be erupted as indicated in satellite observations. Seismicity reached a peak at about 2200 Z (2:00 PM ADT) yesterday and has been gradually declining since. Reports from Unalaska indicate no ash fall in Unalaska/Dutch Harbor since last night. However,…
Okmok Caldera in Alaska's Aleutian Islands erupted today, sending an ash column to at least 30,000 feet. Very little news has been released about the eruption so far beyond this information about the eruption column and some bits about precursor seismicity. A number of flights to Unalaska Island were cancelled due to the eruption. I'll pass on more information when I get it. Okmok is located near Dutch Harbor, Alaska and is a large shield volcano with two prominent calderas at the top. In fact, whenever I see pictures of the caldera, I am reminded of what Crater Lake (Oregon) might look…
There are some astounding new pictures of Chaiten in full eruption over at the Smithsonian Website. There pictures were released by the USGS/VDAP team and show a full eruption column coming from the new dome in the Chaiten caldera (see above and below). The dome itself looks giant, filling up a lot of the old caldera (the highlands around the edge of the dome itself). The eruption is almost the antithesis of the 2004-08 Mt. Saint Helens dome eruptions which has produced a minute dome filling the 1980 crater. This rhyolite dome is the first major rhyolite eruption in almost 100 years, so I…
I found this picture on the SF Chronicle website and it speaks volumes about the destruction wreaked on Chaiten, Chile. The ash has buried the town and what the ash hasn't damaged, the water and debris from the swelled river in the background have finished off. This is what volcanoes can do in the blink of an eye (geologically speaking).
Just when you thought it was safe to go outside. After apparently settling down a bit over the weekend, Chaiten has kicked it back up a notch. The latest reports say that two ash columns are active ... and that is about all we get for more news. Not surprisingly, most of the damage around the volcano has been done by flooding and/or lahars, thanks to the ash and debris-choked rivers like Rio Blanco. It also sounds like the SERNAGEOMIN is digging in for the long-haul, calling for the eruption to go on - to some degree - for months. This isn't too shocking considering the minor dome eruption…
The newest reports out of Chile are indicating that the eruption at Chaiten has reached levels of intensity not seen since the eruption first started over six weeks ago. I have to admit, that isn't a good sign in terms of keeping the volcanic edifice in one piece. There have been frequent, small (<M3) earthquakes along with "rumbling noises," which might indicates that the domes are collapsing to form pyroclastic flows. Alternately (and need I remind you, very speculatively) it might be the the edifice itself beginning to show the wear of this long eruption and the emptying of the magma…
So, this was a bit of a surprise to me. Six weeks into the Chaiten eruption in Chile, apparently the volcano has picked up the tempo again. Not much in the report except that apparently two new vents/craters have opened, there is an increase in ash emission and seismic activity. What this might be is difficult to ascertain from the report, but it could indicate that the volcano might be heading down the road toward a collapse, such as the one previously alluded to by scientist-in-charge Luis Lara. Another report - albeit almost identical to the first - does mention in the headline that the…
If you needed any evidence that Chaiten is still erupting quite vigorously, just check out the MODIS image taken on 5/31 (above). The eruptive column is still delivering ash across southern Chile, over the Andes and into Argentina. This eruption just keeps on impressing me with its duration and magnitude - this is one for the ages (well, human ages).
I always find it interesting how and why news of a volcanic eruption makes it into the press. Sometimes it is just to report the eruption itself, however, a lot of the time it is more to report the "human interest" side of the story, or in this case, the wildlife side of the story. Cerro Azul, one of the volcanoes in the Galapagos islands, apparently erupted on Thursday (5/29). Lavas flows on the northeast side of the volcano are threatening the Giant Galapagos Tortoises and their status (the tortoises and the lava flows) will be monitored. On the volcanic side of things, Cerro Azul last…
We've been hearing a lot of conflicting reports about the state and future of the Chaiten eruption. Now ending its fourth week of eruption, Chaiten was said to be easing up a bit, but recent reports have Luis Lara from the SERNAGEOMIN still worried about a potential collapse, followed by a devastating eruption. I'll have to take his word for it as the explanations in the article don't really make a lot of sense. It sounds like both Lara and Dr. Petrinovic (Argentina) are worried about dome collapse, but that would just form large pyroclastic flows ... unless the dome collapses enough to…
The Oregonian reports on the on-going desire to develop geothermal power in the Oregon and California Cascades and backarc. There have been attempted (or at least exploration) to develop geothermal power at Newberry Volcano, Crater Lake and Medicine Lake, but none have ever panned out. Well, it seems like this time it might happen, and I, for one, think it is a good idea. Of course, there are a lot of folks who don't want a geothermal plant anywhere near Newberry, especially with its National Monument designation, but one of these days we'll have to choose between that and higher energy…
Some news from the Chaiten eruption. Apparently, LanChile has cancelled some flights around the region of southern Chile due to the ash. They likely implies that the eruption column is bigger than reported by the SERNAGEOMIN on Monday, but the report has little in the way of details. Sounds like the volcano is still huffing and puffing away. Definitely one of the more important and interesting eruptions in the last few hundred years and it has the Cascades Volcano Observatory along with the USGS VDAP buzzing (based on some conversations I've had recently), even almost four weeks in.
Although the mainstream media seems to have lost interest in the Chaiten eruption beyond the "human interest" (or should I say "salmon interest") aspect of the eruption, there is still a lot going on at the volcano. The SERNAGEOMIN recently released this excellent photo of the erupting caldera: What is pretty clear here is thank a new rhyolite dome is erupting on top of the old dome. (On a side note, when I was visiting the Smithsonian last week, we were all lamenting the fact that no one has come out and said what composition this lava is? I'm 99% convinced it is rhyolite, e.g., high silica…
I'm always amazed by the number of volcanic eruptions captured by satellites that we might not have ever even had known occurred otherwise. Case in point is Rabaul on the island of New Britain in Papua New Guinea. An Aqua satellite captured this shot of Rabaul erupting on May 20th, leaving a gorgeous plume heading off into the Pacific. Sure, most likely someone might have noticed the eruption, but its good to see that we can find eruptions going on even when we're not really looking. Rabaul is a caldera volcano that is most famous for the simultaneous eruptions of Vulcan and Tavurvur in 1994…
Everyone loves a "supervolcano"*. According to a recent report, Los Angeles will be erupting from underneath Yellowstone Caldera (Wyoming). OK, not really, but apparently there has been 7 cm of uplift underneath the footprint of the Yellowstone Caldera since 2004, which is a pretty good amount of uplift. Whether this uplift is caused by new magma intruding, volcanic gases collecting or hydrothermally spawned (however, in the article, we are to believe these unnamed "researchers" that it is magma). I'll keep an eye out for more on this, but it sounds like this is just another "more uplift!"…
To keep us up to date on the goings-on at Chaiten in southern Chile, well, the volcano is still erupting! Yes, two weeks in and heavy ash is still being erupted from vent. The latest reports are vague, but Chilean officials are saying things like "There's been additional volcanic activity that we're really worried about..." Now, I can only speculate what this means, but this might be an indicate that the SERNAGEOMIN are really beginning to seriously consider that the whole volcano may collapse. The town of Chaiten, even without a collapse, is pretty much been wiped off the map. 90% of the…
A bit busy today, so to borrow from the newest USGS/SI Volcanism Report: On 12 May, the plume rose to an altitude of 8 km (26,200 ft) a.s.l. During an overflight conducted by SERNAGEOMIN, four more plumes of a similar altitude were generated by explosions and drifted NE. Several hectares of burned vegetation, likely from pyroclastic flows or lateral explosions, were noted on the N flank of the dome. Small pyroclastic flows may also have been responsible for completely burned forest to areas in the NE, and on the W and NW dome flanks. A lahar caused the banks of the Chaitén River to overflow…
I just read a report that the ash column at Chaiten is beginning to collapse. The SERNAGEOMIN says that the ash column is only 4.5 km tall now, as opposed to the 20 km it had reached earlier. Still, there are not reports of pyroclastic flows, but that could be a matter of hours or days at this point. We'll be keeping a close watch on the eruption to see if this is the beginning of the end, or just a lull in eruptive activity, here a full 12 days into the eruption. UPDATE 12:20 PM (Pacific Time): According to this new article, the SERNAGEOMIN is reporting the first of the column-collapse…
Here is a gallery of some ridiculously cool photos from the Chaiten eruption ... Â