Strong Ground Motion of the 1923 Kanto, Japan Earthquake

Abstract

The 1923 Kanto earthquake (M_J=7.9) has great significance for seismic hazard assessments of the Tokyo metropolitan area, because it caused extensive damage to the area. To deepen our understanding of the strong ground motion of the Kanto earthquake, this paper reviewed studies on its observed strong ground motion and found that 1) seismic intensity VI on the Japanese scale (IX or X on the M. M. scale) was widely distributed in an area of approximately 8,000 km², which is equivalent of that of the 2011 M9 Tohoku earthquake, 2) strong effects of soil amplification on ground motion were suggested by the correlation of the damage distribution with surface geology, 3) the restoration of the scaled-out seismogram indicated that the ground motion at the upland of Tokyo would be roughly 50 cm/s for maximum velocity and 50 cm for maximum displacement, and 4) the ground motion in the epicentral area is unclear, but would be roughly twice or more as strong as that at Tokyo.