Der Spiegel: Geologists Warning Of “Mega-Eruption”

Der Spiegal via NoTricksZone ^ | 5 November, 2010 | P Gosselin

[Errant]

Errant should check his data for before 30 years ago. Also check for frequency of EQs 7.0 and above.

The data at USGS begins at 1973. The 5.0 chart below looks a little worrisome but we're dealing with a VERY short time frame in geological terms + we can't be too sure of its accuracy. I'll not be held responsible for anyone leaping from a tall structure (blame the USGS). :)

[Errant]

Ping for charts above

[The Comedian]

Thanks for the ping.

Not the most reassuring graphs I've ever seen...

Multi-quakes/tectonics galore.

Frowning takes 68 muscles.
Smiling takes 6.
Pulling this trigger takes 2.
I'm lazy.

[Errant]

Too bad more data isn’t available as it would give a better picture. With what we have, it seems we’re seeing a 33% increase in activity over an average year.

[Quix]

THX

[PIF]

Always a good source to check on theories like the 30 year cycle thingy (unfortuately their data doesn’t go back more than 11,000 years):

Global Volcanism Program|Volcanoes of the World|Large Holocene Eruptions
http://www.volcano.si.edu/world/largeeruptions.cfm

[little jeremiah]

Thank you.

Does tell a bit of a story. Would be nice if the data went further back in time but you have what’s available.

[Errant]

Does tell a bit of a story.

I was very surprised by the rhythm that shows up in the 5.0 chart. I thought that all would show random numbers of earthquakes occur, such as seen in the magnitude 7 and greater chart. This could mean some regularly occurring, underlying event(s) trigger earthquakes. Further investigation may discover what/if this is true and lead to some kind of advanced warning. A 33% increase as we seem to be experiencing now is not insignificant.

I hope the US/world can afford to continue the work that the USGS is doing in collecting this data. It could prove invaluable in solving mysteries about earthquakes and even about volcanoes.

[gleeaikin]

Re the 30 year cycle: I have only been able to follow it since Laki in 1783 at VEI-4, which actually is listed under Grimsvotn. Apparently a big part of the Laki problem was the fact that it erupted over a two year period along a 25 mile fissure. It ejected large amounts of fluorine gas which in addition to ash on the grass killed 90% of the livestock and 10% of the population by starvation. It also put a blue haze over Europe and disrupted the climate to the point where some believe the worsening economic conditions helped provoke the French Revolution. Katla seems to have a major blowout about every 50 years and it is due, but I don’t think it will be the BIG one either, just a lot of trouble for airline traffic.

I am currently collecting data and information for a book about the 1902 Pelee eruption on Martinique. My hero is a young geologist who falls for a lovely young woman from Martinique. An interesting fact is that the entire Caribbean Plate was being disrupted, with Pelee and neighboring St. Vincent each erupting with a VEI-4, Santa Maria in Guatemala with a VEI-6/7, Izalco in El Salvador, Momotombo in Nicaragua, Poas in Costa Rica from 1902 to 1906, and possibly Rincon de la Vieja in Costa Rica and Purace in Colombia. These others were no greater than VEI-3, but all rim the Caribbean Plate. The death toll on the first 3 was around 45,000. One result of all this activity was the decision to put the canal in volcano free Panama instead of Nicaragua.

Interestingly in 1812 (remember the great Mississippi EQ cycle of 1811-12) there was a major EQ in Colombia that killed 20,000 and St. Vincent blew up then too. On either side of the Caribbean Plate activity of 1902 was the Charleston EQ of 1886 and the San Francisco EQ of 1906.

It has been hard to trace things back earlier, but there also seems to be a secondary activity period about midway or slightly later between each 30 year cycle. The great Lisbon EQ (1755?) comes to mind, and Boston had its worst EQ the same month as Lisbon. I have pretty good volcano sources, but not so good on earthquakes. Hope to push the pattern back further. Also, Jaeger (Hawaii Volcano Observator in the 1950’s noticed that magma seemed to rise higher in rhythm with the sun spot cycles.

I wish I could find a source of data on volcanoes earlier than 10,000 years ago. I have those charts. I know that Sakara-jima left a 15 mile diameter caldera/bay 22,000 years ago with a concurrent temperature drop. There is a very large caldera around Vesuvius, but I don’t know its age. Any facts will be appreciated.