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Chaitén – VDAP briefing 19 June 2008

Posted by admin in activity reports, Chaitén, Chile, eruptions, natural hazards.
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On 13 June 2008 the Volcano Disaster Assistance Program of the USGS, who have been working with Chile’s SERNAGEOMIN at Chaitén, gave a presentation to President Michelle Bachelet of Chile which is now available as a PowerPoint (.ppt) file from the USGS ftp site. It can be downloaded directly from this ftp link.*

The presentation is in the usual visually hideous PowerPoint style but is full of information about the Chaitén eruption that has not been available elsewhere. Some of the interesting points to emerge, paraphrased and re-ordered, are as follows:

  • The new lava dome:
    • Current lava dome eruption rate estimated to be greater than 50m3/s (average ~37m3/s)
    • Area ~540,000m2 (900 x 600m)
    • Volume ~55 million m3
    • At current eruption rate it will take less than 3 months to erupt a new dome as big as the one from the old (9400yr) eruption
  • Volcano monitoring in Chile:
    • Of 122 volcanoes in Chile, 40 have been active historically, 20 have completed geological studies, 7 have completed hazard assessments, and 7 are monitored to some degree
    • SERNAGEOMIN has 12 personnel directly involved with volcanism
    • There is one volcano observatory in Chile – OVDAS
    • Chaitén was unmonitored prior to its 2008 eruption
  • USGS/VDAP forecast for Chaitén:
    • The USGS regard Chaitén as a VEI5 eruption (>1km3 magma, ash to 20km; only a few VEI5s each century)
    • With few historical rhyolite eruptions to draw upon, forecasts must rely on analogs from other types of dome-forming eruptions
    • Although explosive activity and seismicity are both declining, lava dome extrusion will likely continue, possibly for months
    • Statistically Chaitén is unlikely to return to a highly explosive character – of 252 large eruptions (>VEI3) 63% had maximum explosivity within 1 month, and of 3301 eruptions with known start and stop dates, 71% lasted <6 months
    • Continued close monitoring is needed to watch for change in eruptive pattern
    • Hydrologic disruption will persist for months to years

* You’ll need a browser that’s happy handling ftp downloads to get the file – I couldn’t make it work in Internet Explorer, but Mozilla was fine – and PowerPoint, or the free PowerPoint Viewer, to see the presentation.

Many thanks to commenter Hawkeye for locating this presentation.

For all our Chaitén coverage: Chaitén << The Volcanism Blog

Global Volcanism Program: Chaitén – summary information for Chaitén (1508-41)
ONEMI, Oficina Nacional de Emergencia – Chilean government emergencies office (Spanish)
SERNAGEOMIN – Servicio Nacional de Geología y Minería (Spanish)

The Volcanism Blog


1. Lisa Gentry - 20 June 2008

are there any new release on the amounts of CO2, ash, and the other hazardous gasses that have come out in the ash plume? I know for about a month, it’s been mostly water vapor and I know varying levels from about a month ago, but haven’t found anything lately.

2. Fresh Bilge » Chaitén Update 21 - 20 June 2008

[…] lava dome at The Volcanism Blog, I have been in a state of shock and awe. This evening, via another TVB post, I have learned another astonishing and alarming […]

3. Erik Klemetti - 20 June 2008

I’m glad someone found this presentation … it has some great information, especially with the VEI 5 ranking of the eruption.

4. Claudine Mangen-Sales - 21 June 2008

So it won’t collapse?
What do you think will be the repecussions of all this ash in the air on the weather next year? Does someone have an idea?
Very interesting blog

5. Lisa Gentry - 22 June 2008

It MAY still collapse, it’s just not clear yet if it will. With new vents and plumes, it’s still seeming fairly active. Do you remember the repercussions of Mt St Helens eruption in 1980 and how it continued for 4 years? The first year after was somewhat colder, but the ash and effects stayed in the northern hemisphere, and mostly were restricted to North America. They will likely get a degree or so cooler, have pretty bad vog/smog in the area until it can settle due to normal means, but the areas that have gotten a layer of ash will in the near future have fairly fertile soils. Just a thought.

6. Chaitén - updated VDAP briefing « The Volcanism Blog - 9 August 2008

[…] VDAP gave a presentation to President Michelle Bachelet of Chile (TVB post about the presentation here), and the latest briefing, given on 6 August for the benefit of the Office of U.S. Foreign […]

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