2013 Volume 1 Issue 1 Pages 379-397
On March 11, the 2011 off the Pacific Coast of Tohoku Earthquake occurred and the huge tsunami widely ravaged the coast, carrying sediments inland. Because the sandy layer deposited by the past tsunami is well known to be one of the effective indexes to know the occurrence of the great earthquake in the past, it is very important to investigate the sand sediments left by the above great earthquake.
In this study, a field survey on the soil sediments was conducted at 33 sites of three cross-sections along the Sendai Plain in Miyagi Prefecture. Furthermore, 54 soil samples were dug at each site and grain-size distribution tests were conducted to study the characteristics of the soil sediments in detail.
The results of the study show that the fundamental characteristics of the sediments in this tsunami can be described as “fining upward” and “landward fining”, and the relation between the thickness of sand sediments and the distance from the coastline at the Sendai Plain can be obtained from the other investigations.