1923年関東地震による震生湖地すべりの地質構造とその意義

Abstract

1923 Kanto earthquake induced numerous numbers of landslides in the western part of Kanagawa Prefecture. In particular, a landslide dam made in Hadano still remains and its lake is known as a quake lake. However, the geological structure of the landslide was not clarified. We made geological and geomorphological investigations for this landslide, using drilling and airborne LiDAR, then found that this landslide had its sliding surface along Tokyo Pumice in the depth of about 17 m and the overlying volcanic soil and pyroclastic flow deposits slid. Tokyo Pumice erupted from the Hakone volcano 66 thousand years ago and is widely distributed in Kanagawa and Tokyo, suggesting that potential earthquake-induced landslides must be considered.