Three-dimensional tsunami runup simulation for the port of Koborinai on the Sanriku coast of Japan

Abstract

Kim, D.C., Kim, K.O., Pelinovsky, E., Didenkulova, I. and Choi, B.H., 2013. Three-dimensional tsunami runup simulation for the port of Koborinai on the Sanriku coast of Japan.The huge tsunami generated by the earthquake that occurred off the Pacific coast of Japan at 14:46 JST (05:46 UTC) on Friday, 11 March 2011 produced a maximum runup of 40 m on the east coast of Japan. The earthquake triggered extremely destructive tsunami waves up to 37.9 m in height that struck Japan minutes after the quake. Koborinai is a tiny fishery port located north of Miyako City in the Iwate Prefecture. A survey team from the University of Tokyo Earthquake Research Institute (ERI) found high water marks and other evidence of a gigantic wave at the port of Koborinai. The port is on low land sandwiched between two mountains. A joint survey team from ERI-Sungkyunkwan University (SKKU) and Korea Ocean Research & Development Institute (KORDI) visited again and surveyed the site in detail. The 3D Princeton Ocean Model was applied to describe the propagation and runup of the tsunami on the Japanese coast. The numerical simulation results obtained were in satisfactory agreement with observations made in the general area, except those made in many v-shaped valleys along the northern Iwate coast. The extremely high runup of tsunami waves at the port at Koborinai were successfully reproduced by numerical simulation through stepwise refinement of the spatial scale using multi-nesting and consideration of the vertical acceleration of flow along steep slopes using a CFD model to solve the Reynolds-averaged Navier–Stokes (RANS) equations. The velocity field was also computed, and the simulation results show that the water flow that climbed the coast possessed a strong vertical velocity component.