Tsunami Inundation Modeling of the 2011 Tohoku Earthquake Using Three-Dimensional Building Data for Sendai, Miyagi Prefecture, Japan

Abstract

AbstractIn conventional modeling of tsunami inundation, based on nonlinear shallow water theory in a finite-difference scheme, the effect of buildings and structures is represented by a bottom friction parameter rather than by three-dimensional (3D) building shapes. But large, strong buildings should offer direct protection against an incoming tsunami, like seawalls. In this study, therefore, we incorporated 3D building data obtained from lidar measurements in modeling the tsunami from the 2011 Tohoku earthquake at the port of Sendai, Miyagi Prefecture, Japan, and compared the results from conventional modeling based on a digital elevation model. In the model incorporating 3D building data, the maximum inundation height was greater than in the conventional model at the front of coastal buildings and structures and smaller behind them. High-velocity currents appeared in the corridors between these buildings, and the tsunami inundation area was smaller in the residential zone because of the obstacles that buildings presented to the tsunami. These results mean that solid buildings and structures have a significant influence on the propagation of tsunamis on land. The effects of the 3D shapes of buildings and structures should be further investigated for detailed tsunami hazard assessments in urban areas.Keywords2011 Tohoku TsunamiTsunami modeling3D Building data