Chile Forum

i'm not sure if most of you on the forum are aware of the early warning monitoring systems in place for the more active volcanoes in chile, but there does seem to be some work done in this regard using the USGS model for volcanoe monitoring in the US.

currently, Chaiten is at Level 3, Yellow with an expected probability of a re-eruption in weeks to months, from the last report released in mid-march 2011:

"NIVEL 3 - AMARILLO: CAMBIOS EN EL COMPORTAMIENTO DE LA ACTIVIDAD VOLCÁNICA II -
Tiempo probable para una erupción: SEMANAS a MESES"

it was at level 4 Yellow last June, downgraded July 2010, with similar eruption probabilities.

I don't believe I'm allowed to post links yet, so please search for the OVDAS website and follow the "Informes" link to find a list of recent and historic reports.

the reports look to be updated at least monthly, with occasional special reports during anomalous activity. the normal reports are labeled RAV, while the anomalous reports are labeled as REAV. the REAV reports seem to be posted on the day of the anomalous event (and looking at times, sometimes within an hour of the event), so it may be worth trying to use google reader to monitor any page changes if you live in the region of an active volcano.

hopefully some of you find this useful, as this forum has been incredibly useful in finding information about chile for me.

slds

Search the forum for chaiten thread, and you will see that allchile.net was the only early warning system functioning when it went nuclear (vicky posted mins after feeling the first tremors in futa). The "experts" did not even know it had erupted until 24 hours after. They thought it was another volcano, because there were no sensors on it but neighboring volcano was being monitored.

yes, i read that thread. that one, the earthquake thread, and the patagonia rebellion thread (among others) show the great value of the forum in providing a network of information about real-time events.

the current reporting system of OVDAS was started in response to chaiten, with nothing really present in the country (reporting-wise) before that. their goal is/was to install real-time monitoring systems on 42 of the 100 or so volcaones in chile that have been deemed the most threatening to prevent another repeat event like that or worse. i think they've made some decent headway in that regard.

the value of early warning systems, is that the seismic activity from volcanoes in many cases start days to weeks (if not months) prior to the eruption (vs minutes), and which may be difficult to detect by individuals and certainly difficult to discern whether volcanic in nature or not. there is a paper floating around that analyzed the seismic events given off by chaiten at the seismograph that was 300km away. the conclusion was, 3 days prior to the chaiten event there was significant background seismic activity (every hour) that had a high probability of originating from chaiten which demonstrated highly anomalous patterns, that IF were to have been captured by a chaiten specific meter would have given clear early warnings that something was a brew.

The problem with Chaiten was that no one knew it was active, and had not been for 10,000 years or so. A lot of the people living in Chaiten really did not know it was even a volcano. It was just the mountain in their backyard. Knowing to stick a monitor on it, implies knowing it is something to be worried about. There are hundreds of them in Chile that are more or less unstudied, let alone monitored. Lot's of them are under the ocean.

I think overall, better money should be spent on increasing the overall seismic grid of Chile and reporting. Obviously, monitoring the troublemakers is useful, but so too being able to monitor more.

The big boys, like Osorno and Llamia near population zones are monitored and have been for a long time.

admin wrote:The problem with Chaiten was that no one knew it was active, and had not been for 10,000 years or so. A lot of the people living in Chaiten really did not know it was even a volcano.

"They" should have known it was a potentially active volcano since the rest of the world did. The Chilean press did a great job of excusing the government for another failure. It turned out that the "no eruptions for 10,000 years" was something that the press ate up as part of the exculpatory process, and once published, people tended to stick with it. But it turns out that there is lots of evidence that the Chaitén dome has erupted in recent times. If you read the proceedings of SERNAGEOMIN [‘Volcanismo en Chile y Red Nacional de Vigilancia Volcánica’ October 2008] you will find that there are likely two significant eruptions of the Chaitén dome itself as recently as the beginning of the 19th century. These were probably visible from Chiloé. The Carretera Austral north of Chaitén also crosses a fairly recent lava flow from that volcano, which extends out to Punta Chana. But the post-eruption research has not been widely acknowledged by Chilean media, preferring to rest on the earlier but discredited 10,000 year figure instead.

The 2008 eruption was part of the Minchinmávida volcano chain of which the nearby Chaitén volcano is a part. The Chaitén dome is only about 8 miles from the known-active Minchinmávida. Minchinmávida and Chaitén volcanoes are believed to share the same magma feeds. Even if the Chaitén dome had been ignored, the larger nearby Minchinmávida has a history of eruption as recently as the 19th century that is well recorded. Even Darwin took note of it. The failure to monitor a known-active string is just another screw-up, especially since Chaitén was the provincial capital until the eruption. The events were another kick in the arse for Servicio Nacional de Geología y Minería which is supposed to be monitoring these things.






Welcome to Chile. Naw, don't you worry about that old volcano.

image: Px crossing from Quellon (Chiloé) to Chaiten with BMW R80 GS, 1997. Corcovado volcano visible; also active volcano in 19th century .


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