Earthquake, Geology, and Tsunami

Abstract

On March 11, 2011, a huge subduction zone earthquake occurred offshore of the Tohoku district, Japan, and created devastating damage, primarily due to the very high tsunami tide along the Pacific Coast. We first review several source studies and then summarize basic characteristics of observed strong motions with reference to the attenuation relationships, response spectra, linear site factors in the region, and nonlinearity. Fortunately we haven't seen heavy damage concentration even in the areas with high Peak Ground Accelerations, because Peak Ground Velocities were not high enough to make buildings heavily damaged or collapsed. The locally deployed network data as well as observed building responses are briefly summarized. Topographic maps and geological maps of Tohoku district and Kanto district will be shown. Finally, statistics of inundation survey, water level time -histories, and examples of damage for tsunami in Tohoku district will be presented. © Springer Japan 2012.