IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS002 Poster presentation 1809
Historical and holocene paleotsunami deposits on Minor Kurile Arc
Dr. Razzhigaeva Nadya
paleotsunami paleotsunami
Larissa Ganzey, Tatiana Grebennikova, Andrey Kharlamov, Alexander Ya. Ilev
The data obtained describes the results of grain size and mineralogical study of tsunami 1994 deposits
on Shikotan, Tanfiliev and Kunashir Islands. Investigations carried out within the coast with different
configuration, geomorphologic structures, lithodymanic environments and tsunami character. Tsunami
deposits composition were mainly controlled by erosion-accumulative processes during tsunami events
and are in many respects inherited from sources material. Tsunami deposits include marine diatoms,
rich assemblages were found within areas, where material from offshore redeposited. Data of deposits
of earlier historical tsunami from the same sections are discussed too. The study of these deposits
indicates similar development of erosion-accumulative processes during tsunami events with the same
intensity and gripping the material for the same sources. Paleotsunami traces were studies in Shikotan
and Zeleniy Islands coastal peat bogs and lacustrine sequences that were deposited during last 6 ka.
The results will be used for detail catalog of tsunami events for South Kurile Region. The age of these
events was based on radiocarbon dating and tephrochronology, some tsunami parameters (wave
height, inundation area) for different coasts, and frequency were estimated. The marine origin of the
sands was confirmed by some analysis including diatom data. Paleotsunami frequency was irregular,
high reiteration of the events took place during Late Holocene. The data are presented for concrete
coasts. Largest amount of paleotsunami sands were found on Pacific side of Shikotan Island. Some sites
with numerous tsunami sands may be used as key sections. Grain size composition of tsunami sands
was analyzed and compared with other coastal facies. Sources of paleotsunami material were
established. Tsunami sediments are consisting of terrigenous and pumice sands which had different
sedimentation features. Some tsunami and volcanic eruptions were synchronously. Grants RFBR 05-05-
64063, FEB RAS I № 06-I-ОНЗ-106.
Keywords: tsunami, sediments