caldera
eklemetti | May 12, 2008
I've been trying to keep up with the Chaiten eruption in Chile, but the news is just beginning to sound like a broken record: eruption continues, ash falls, don't know much else. However, it does sound like Chile is being realistic about people's chances of moving back to the town of Chaiten - 10 km from the vent(s) - in the near future ... and those chances are zero to none. This doesn't entirely surprise me. If the town isn't already buried, when the pyroclastic flows do start, whether they be from the collapse of the the eruptive column or from the vents themselves, the town will be…
eklemetti | May 10, 2008
Before we get too far, I wanted to make sure that folks understand that I'm just making educated conjectures on the nature of the eruptions I read about and by no means do I have any extra insight over those scientists on the ground at the eruption. I have a very limited set of data to examine - whatever the media reports - so I am just speculating based on what I know about the eruption style, volcano in question and whatever other variables might come into play. So, please, don't think that I know exactly what is going on or what will happen better than the scientists tackling the volcano…
eklemetti | May 9, 2008
This marks a full week of eruption at Chaiten and the volcano shows no signs of abating.
You have to feel for Luis Lara. He is apparently the pointman for the SERNAGEOMIN in regards to this eruption and really, I think its anybody's guess what might happen next. Heck, we haven't seen many eruptions of this scale - and this out-of-the-blue - since the birth of modern volcanology, so we're testing a lot of hypotheses now. What Dr. Lara says is that the eruption is still going strong, lava flows seem to be occurring at/near the vent but not spilling out of the caldera, the two vents have…
eklemetti | May 8, 2008
Another day, another development at Chaiten. Military stationed near the volcano helping with evacuations reported "booming noises" and saw incandescent blocks getting hurled from the vent area. This suggests that lava is at the surface and potentially that the edifice itself is beginning to crack/strain from the loss of material from the eruption. Remember, when you erupt all this volcanic material, you leave a void under the volcano where that magma used to be, so suddenly you have a volcano with no foundation. Sometimes they can founder into that space, forming a caldera. We already…
eklemetti | May 7, 2008
The eruption at Chaiten has now begun to have widescale effects on the region of Patagonia, beyond the ashfall. Air travel has been disrupted due to the amount of ash in the air. It is well-documented that ash posed a significant hazard to aircraft, so this seems like a wise move on the parts of Argentina and Chile.Â
Not much else new to report beyond that the fact that this eruption is now into day 6 without any signs of letting up. Impressive to say the least.
eklemetti | May 6, 2008NASA captured this great image of the ash plume from Chaiten, which has reached 15-km into the atmosphere.
Following this eruption, I'm sure there will be a lot of work into why no one had any clue an eruption of this magnitude was about to occur.
eklemetti | May 6, 2008
Well, this is getting rather harrowing. Volcan Chaiten, the Chilean volcano that sprung back to life last Friday after anywhere between 2,000 to 7,000 of quiet, is apparently erupting lava along with ash now. Sounds like its a good rhyolite/rhyodacite lava based on the description: "very small and very thick and as such was moving slowly so it is moving very slowly''.
Chilean officials are now fearing that the volcano is in "worst case scenario"Â mode - although, they never mention what that might be: full-on caldera? topography-erasing ignimbrite? Pinatubo-scale eruption? However, the…
eklemetti | May 5, 2008
For those of you who have missed it, Halemaumau Crater at Kilauea (Hawai'i, USA) have been experiencing new eruptions - some of them explosive - for the last couple months. These are the first eruptions at Halemaumau since the 1980s and the first explosive eruptions at Kilauea since the 1920s. Much of the area around the crater in Hawai'i Volcanoes National Park are closed due to the volcanic gases and the potential for more explosive eruptions to throw material out of the crater. These explosive eruptions are likely caused by the interaction between the magma below the surface intersecting…
eklemetti | May 5, 2008Monsters and Critics has some truly fabulous images of the ongoing eruption at Chaiten in Chile.
The pictures of the extent of ash fall are quite remarkable. It is hard to tell exactly how deep the ash is or how far from the vent these pictures were taken, but one can imagine that if a helicopter took them, then they are relatively far from the action. The Chilean President, Michelle Bachelet, toured the area to see the damage. Stunning stuff.
eklemetti | May 4, 2008
Update 5/4/08: Looks like there is now officially a deathtoll for Chaiten, as an elderly woman died during the evacuations. The volcanoes continues to spew ash and I wouldn't be surprised if it did so for at least a few more days. There have also been reports of a sharp increase in earthquakes in the area since the eruption. Now, before everyone goes nuts, this could be just a response to the dramatic release of pressure caused by the eruption, possibly faulting in the caldera walls activated by the eruption, or possibly magma working its way to the surface as the eruption progresses.…
eklemetti | May 3, 2008
Update 5/3/08: SERNAGEOMIN (the Chilean Geologic Survey) is now concerned that the eruption of Chaiten may be a the precursor of a larger eruption, mostly owing to the long (~9,000 year?) repose time. This could be the beginnings of a southern Andean Pinatubo.
The towns around Chaiten are more or less deserted now as the volcano continues to spew ash and pumice - upwards of 15 cm of ash in some places.
Edit: fixed link (thanks Mark)
Edit 2: fixed date of last eruption from ~7,000 years ago to ~9,000 years ago.
eklemetti | May 2, 2008
The big eruption news today is an unexpected eruption in southern Chile. In fact, it is so unexpected that depending on when and where you read about it, you might get a different answer to what volcano is doing the eruption. What we do know at this point is an eruptive column has been spotted by people on the ground and the Washington VAAC, with estimates of an eruptive column height of between 35-55,000 feet. In other words: pretty darn sizeable. Ash is also coming down in town to the east of the eruption in Argentina. Now it seems that Chilean officials say Volcan Chaiten is the culprit…
gregladen | November 10, 2007As you have surely heard, the Yellowstone Caldera ... the place where Old Faithful and the Geyser Basin reside ... has been undergoing increased "activity" including some earthquakes and a rising up of the land. Is this a big problem? Should the evacuate? Should those of us living only a few states away start wearing earplugs?
The paper reporting this, in the current issue of Science, concludes:
The caldera-wide accelerated uplift reported here is interpreted as magmatic recharge of the Yellowstone magma body. Although the geodetic observations and models do not imply an impending volcanic…