Tsunami Deposits of Tokai Earthquakes Preserved in a Coastal Marsh Sequence at Osatsu, Toba, Central Japan, And Their Magnetochronological Dates

摘要

The coastal northeastern part of the Kii Pen- insula, southwest Japan, has great potential for suffering tsunami disasters in the future. In order to investigate the past tsunami events recorded in Holocene sediments, an oriented box core sample 3.5meters long was obtained from the marsh in Osatsu, Toba City. The core sample lithologically consists of eleven layers (A-K layers); all except B and D are composed of mud and sandy mud deposited in fresh water environments.