HR: 13:40h
AN: OS13B-01 INVITED    [Abstracts]
TI: A Decade of Tsunami-Deposit Studies in the Russian Far East – Opportunities and Challenges
AU: * Bourgeois, J
EM: jbourgeo@u.washington.edu
AF: Earth & Space Sciences, Univ. of Washington, Seattle, WA 98195-1310, United States
AU: Pinegina, T
EM: tsunami@kscnet.ru
AF: Institute of Volcanology & Seismology, Piip Blvd 9, Petropavlovsk-Kamcha, 683006, Russian Federation
AB: Pioneering tsunami-deposit studies by I. Melekestseev and T. Pinegina led to an extensive (and ongoing) field campaign on Kamchatka and the Kuril Islands over the last ten years. This work has included large teams of Russian and American scientists and students, funded primarily by NSF Earth Sciences and Biocomplexity, the Russian Foundation for Basic Research, and institutes of the Russian Academy of Sciences. This region has rich history of 20th-century tsunamis, so most localities have a historical deposit to compare with paleotsunami deposits. In the time frame of our campaign alone, there have been two large tsunamis generated in the Kuril-Kamchatka subduction zone (Kronotsky 1997; middle Kurils 2006). Moreover, because the volcanic arc associated with the subduction zone is also very active, volcanic ash layers (tephra) serve as important correlation and dating tools for historic and pre-historic deposits. Some accomplishments of our work include: 1) quantification of (paleo)tsunami frequency north of the active volcanic arc, in the SW Bering Sea, supporting presence of a plate boundary in this region; 2) ongoing quantification of (paleo)tsunami frequency at more than 30 localities along 1000 km of coastline; 3) documentation of runup for important historical tsunamis in unpopulated regions (e.g., 1737, 1923, 1952, 1969, 1971, 1997, 2006); 4) modeling of tsunami source regions to attempt matches with runup patterns, illustrating cases of source- region heterogeneity (1952, 1997, 2006?]; 5) generating a benchmark case for modeling (paleo)tsunami sediment transport. Challenges in these studies have included (not counting remote access and bears): 1) correlation of deposits over any distance – from within a single profile to inter-locality (sometimes easy, commonly difficult); 2) paleotopographic (and paleobathymetric) reconstruction – the former is more critical because more likely to have changed over centuries to millennia; 3) given the above challenges, it is difficult to develop methods for statistical treatment of the field data – e.g., how many tsunamis of what size in how many years?; 4) access to good bathymetry and topography (and then digitizing it). This presentation will focus on challenges, which are common to all paleo-tsunami studies, and on ongoing research. Moreover, we plan to offer new sets of benchmark data for tsunami-sediment studies from the 2006 middle Kurils tsunami.
DE: 4564 Tsunamis and storm surges
DE: 7221 Paleoseismology (8036)
DE: 8104 Continental margins: convergent
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting