HR: 15:25h
AN: GP43C-08    [Abstracts]
TI: How Many and What Kinds of Plate Boundaries? Neotectonics North of the Active Arc, Kamchatka, Russian Far East
AU: * Bourgeois, J
EM: jbourgeo@u.washington.edu
AF: Dept. Earth & Space Sci., Univ. of Washington, Seattle, WA 98115-1310 United States
AU: Pinegina, T
EM: pinegtk@kcs.iks.ru
AF: Inst. Volcanology & Seismology FED RAS, Piip Blvd. 9, Petropavlovsk-Kamcha, 683006 Russian Federation
AU: Titov, V
EM: vasily.titov@noaa.gov
AF: JISAO/UW, NOAA/PMEL, 7600 Sandpoint Way NE, Seattle, WA 98115-6349 United States
AB: The Ozernoi Peninsula on Kamchatka exhibits neotectonic evidence comparable to many subduction zones, although this peninsula is north of the Kuril-Kamchatka subduction zone as identified by active volcanism and intense seismicity. This evidence includes active thrust faulting (Ozernoi tsunamigenic earthquake of 1969), Holocene marine terraces (uplift rates of ca. 1 mm/yr), tsunami history (recurrence of tsunamigenic earthquakes about 200 yr), uplifted Quaternary marine terraces (uplift rates of at least 0.1 - 0.3 mm/yr), and Quaternary arc volcanism (albeit of an unusual chemistry). Karaginsky Island shares some of these same characteristics, though its neotectonics is not yet investigated in detail. We have also calculated convergence rates of about 15 mm/yr for the Ozernoi-Komandorskiy Basin juncture based on a fault-plane solution consistent with tsunamigenesis for the 1969 Ozernoi earthquake, extrapolated back for 2000 years, based on tsunami recurrence. Such a result, coupled with patterns of historic seismicity and Quaternary and Holocene marine terraces, suggests that Kamchatka may belong to an Okhotsk plate, perhaps as far north as Karaginsky Island, interacting with a Bering plate.
DE: 7221 Paleoseismology
DE: 8123 Dynamics, seismotectonics
DE: 8150 Plate boundary--general (3040)
DE: 8158 Plate motions--present and recent (3040)
DE: 4564 Tsunamis and storm surges
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting