HR: 09:35h
AN: V21C-07    [Abstracts]
TI: Major Holocene Marker Ash Layers on Kamchatka Peninsula, NW Pacific, and Their Implication for Dating Paleoseismic Events
AU: * Ponomareva, V
EM: ponomareva@ginras.ru
AF: Inst. of Volcanology & Seismology FED RAS, Piip Blvd. 9, Petropavlovsk-Kamcha, 683006 Russian Federation
AU: Bourgeois, J
EM: jbourgeo@u.washington.edu
AF: Dept. Earth & Space Sciences, Univ. of Washington, Seattle, WA 98195-1310 United States
AU: Braitseva, O
EM: Nataliya_I_Florenskaya@svyazinvest.ru
AF: Inst. of Volcanology & Seismology FED RAS, Piip Blvd. 9, Petropavlovsk-Kamcha, 683006 Russian Federation
AU: Kozhurin, A
EM: kozhurin@ginras.ru
AF: Geological Institute, Pyzhevsky per., 7, Moscow, 119017 Russian Federation
AU: Kyle, P
EM: kyle@nmt.edu
AF: Dept. Earth & Env. Sci., New Mexico Tech 801 Leroy Place, Socorro, NM 87801-4796 United States
AU: Pinegina, T
EM: pinegtk@kcs.iks.ru
AF: Inst. of Volcanology & Seismology FED RAS, Piip Blvd. 9, Petropavlovsk-Kamcha, 683006 Russian Federation
AU: Tibaldi, A
EM: alessandro.tibaldi@unimib.it
AF: Dept. Geol. Sci. & Geotech., Univ. of Milan-Bicocca P. della Scienza 4, Milan, 20126 Italy
AB: The Kamchatka segment of the Pacific "Ring of Fire" is one of the most active seismic and volcanic regions in the world. During the last 10,000 years it has produced more than 30 large explosive eruptions with tephra volumes of 0.5-170 km$^{3}$. Widespread on-land tephra layers formed by these eruptions have been identified, dated and studied to develop their mineralogical and geochemical fingerprints. The direct tracing of marker tephra layers along lengthy traverses has allowed us to define ashfall axes and areas of ash dispersal to produce isopach maps. These data can be used for long-distance correlations with deep-sea cores and Greenland ice cores. Tephra horizons are formed instantaneously and thus can provide precise correlation of certain stratigraphic levels in various depositional sequences. We report here implications of this extensive tephra data set to dating and correlation of paleoseismic events such as tsunami, seismically triggered landslides, and episodes of faulting along a major Kamchatka fault zone. Because the historical record of earthquakes and tsunamis on Kamchatka is short (~200 years), these investigations can make important contributions to evaluating tsunami and seismic hazards. Using key marker tephra as time lines, we can compare tsunami frequency and intensity records along the Kamchatka subduction zone as well as compare records of faulting events in various parts of the fault system. The combined record of paleoseismic events and largest explosive eruptions in Kamchatka offers an unprecedented opportunity to correlate seismic and volcanic constituents of the tectonic process.
DE: 8400 VOLCANOLOGY
DE: 8404 Ash deposits
DE: 7221 Paleoseismology
DE: 8150 Plate boundary--general (3040)
DE: 4564 Tsunamis and storm surges
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting