COLLAPSE OF SEA CLIFFS DUE TO THE 2011 GREAT EARTHQUAKE AND SUBSEQUENT TOPOGRAPHIC CHANGES

Abstract

 A massive earthquake with a magnitude of 9.0 occurred on March 11, 2011, at 14:46 with an epicenter 130 km offshore of Oshika Peninsula in Miyagi Prefecture. Due to the earthquake, sea cliffs were collapsed at many coasts. In this study, three examples were briefly introduced: sea cliff at Point Kunosaki south of Hirakata fishing port, sea cliff at the Akahama coast 1.5 km north of Point Takadobana and sea cliff at the Osawa coast facing Uraga Strait. Topographic changes due to waves were monitored after the collapse at the Osawa coast. The scale of the collapse of sea cliff increased over time.