HR: 1340h
AN: T13C-1381    [Abstracts]
TI: Reconstruction of Holocene Seismic Events Along Kamchatka's Pacific Coast
AU: Pinegina, T
EM: pinegtk@kcs.iks.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 98185-1310 United States
AB: Since 1995 we have been conducting detailed neotectonic and paleoseismological field studies of the Holocene at more than 15 localities along the east coast of Kamchatka. Specific methods of these investigations include 1) application of tephra chronology and tephra stratigraphy for dating and correlation of various types of coastal deposits and landforms; 2) study of paleotsunami deposits in order to determine their ages and recurrence rate and to estimate the magnitude of large tsunamis and tsunamigenic earthquakes along the Kurile-Kamchatka subduction zone and north of the latter during Holocene time; 3) analysis of the geologic structure, age, and modern and paleo-topography of marine terraces and beach ridges in order to determine the direction and scale of seismotectonic movements over different time intervals; and 4) identification and dating of inferred seismogenic landslides along the coast. Eastern Kamchatka's short history (since about 1730 A.D.) includes many large and several great earthquakes, although historical coverage of these events is scarce because of both low population density, and also military secrecy. Nevertheless, we can use historical earthquakes and tsunami deposits as benchmarks for pre-historic events. Moreover, our studies have helped elucidate historic cases, including co-seismic deformation, tsunami runup, and tsunami source mechanism. As a result of these studies we have reconstructed key events in coastal evolution during the Holocene, and determined the ages of marine accumulative landforms on various segments of the coast. A combination of all our data enables us to get an idea about spatial and temporal distribution of strong subduction-type earthquakes along the Kuril-Kamchatka trench and 'non-subduction' earthquakes north of the trench terminus.
DE: 7221 Paleoseismology
DE: 8123 Dynamics, seismotectonics
DE: 4564 Tsunamis and storm surges
DE: 3020 Littoral processes
DE: 1824 Geomorphology (1625)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting