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Kuril Islands Biocomplexity

Hi Misty-

I thought of you many times last week. There was an earthquake in the Aleutians of over 6. I'll bet you didn't feel anything, you would have noted it I'm sure.

In reading your journals about recording tsunami damage, there were a few questions.

Have any of the tsunamis damaged the dig sites?

Have the tsunamis exposed something that would have gone undiscovered if they hadn't tore away the beach/land?

As tsunamis tear away, so volcanoes add. Have you come across layers of ash/volcano eruption stuff as you are digging so you could tell when a volcano erupted?

I am sending some of the hot and dry weather that we are experiencing up to the Kurils in a rare reverse cyclonic air flow. My students are requesting that you send the cold rainy weather down here so we can stop our water rationing. 

warmly,

Maggie et all 

 

 

Mon, 08/13/2007 - 13:44

Misty Nikula

Maggie As always, very thought-provoking questions!
Thanks for the warm weather wishes! We have had pretty nice weather the past 3-4 days, so....maybe the rain is headed your way!
We DID feel 3 earthquakes in 24 hours the day before the webinar - but I don't know where they might have emanated from. We haven't felt any since then... Quite frankly, we haven't been to enough of the sites to determine if the tsunami damaged them. However, many of the known dig sites are on the Okhotsk side of the islands and/or on top of the terraces, so it is less likely that the tsunami would have damaged them directly. But again, we haven't revisited all of the known sites and there is some controversy about whether sites exist (or once existed, but have been lost to tsunamis or other catastrophes) that we haven't found on the Pacific side of the islands.
Often sites are exposed by "natural erosion", which I suppose includes tsunamis, but is more often from more gradual beach or river bank erosion. In Ainu Bay, on Matua, there WAS some archaeological material uncovered by the tsunami erosion. It was a site that we were aware of and had dug some test pits in last year. All along the large erosional scarp, at about the same level below the original surface and right above a distinctive yellow brown tephra, there was charcoal and poorly preserved bone that we could see along the erosional face. Since the site was now exposed and would likely continue to be eroded away and "lost", Mike Etnier, Matt Walsh and Dima Chvagian hiked over on August 8 (the day that I returned to the ship) to sample and record it better.
As for your volcanic layers question - yes. There are quite often layers of volcanic deposits - called tephras - which are distinctive and can be tied with relatively good certainty to a specific large eruption. That is one of the primary objectives of the volcanologists is to determine the eruptive histories and the distinctive features/chemistry of major volcanoes on the islands in order to correlate these tephras with a volcano and date. Sometimes tephras have a distinctive color or composition or grain size. They will vary in thickness dependent upon how close you are to the source, of course. Tephras that we know came from a certain eruption and can be dated are called "marker tephras". For example, there is a tephra that can be found on Paramushir that varies from about 20 centimeters or so in the north to 10 centimeters or so in the south that is distinctly light yellow brown and very fine grained. It is called the Kuril Lake tephra and came from the large, caldera-producing explosion of a volcano on the southern end of Kamchatka Peninsula that happened about 7500-8000 years ago.
There is more about that and an excavation that I dug on Paramushir where I found that tephra in my August 21-22 journal from last year.
Hope that helps! Misty

Mon, 08/13/2007 - 19:33

Kirk Beckendorf

Misty,When you felt the quakes were any precautions taken for a possible tsunami. Now that the results of the tsunami have been seen are any precautions in place in case of additional quakes?
Be safe out there!!!
Kirk