Takaaki Uda, Kazuya Sakai, Yukiyoshi Hoshigami, and Yasuhito Noshi

Abstract:
The massive earthquake with a magnitude of 9.0 occurred at 14:46 on March 11, 2011, with an epicenter 130 km offshore from the Oshika Peninsula in Japan¡Çs northeastern Miyagi Prefecture. After the earthquake, large tsunamis were generated owing to abrupt crustal subsidence and uplift, which inundated Japan¡Çs eastern Pacific Ocean coastline. We carried out field observations to investigate the deformation of a previous river-mouth bar by comparing oblique photographs, and investigated the damage to seawalls and the tsunami inundation depth on the Iwama-Sanuka coast, located north of the Same River in southern Fukushima Prefecture. Here, the results of the field observations on the deformation of the sandy beach and the inundation of the Iwama-Sanuka coast are reported.

Keywords: The 2011 Tohoku Earthquake Tsunami, Iwama-sanuka coast, inundation, shoreward sand transport, shoreline change