Field Observations And Numerical Simulations Of The 2011 Tohoku Tsunami Using Comcot

The objectives are two-folded: first summarizing field observations made in 2012 and secondly presenting results of numerical simulations of the 2011 Tohoku tsunami. First, this paper summarizes our field observations made along the coastlines of Miyagi and Iwate Prefectures in the Tohoku areas in 2012, including the cities of Ishinomaki, Onagawa, Minamisanriku, Kesennuma, Rikuzentakata, Ofunato, and Kamaishi. Some peculiar observations are reported, including the overturned buildings at Onagawa. Secondly, tsunami simulations were performed using COMCOT (Cornell University based program) based on linear shallow water equations. The resolution of the bathymetry used is based on 1 minute grid downloadable from NOAA website. Three focal mechanism models proposed by United States Geological Survey (USGS), Chinese Academy of Sciences (CAS) and Tsukuba University (TU) were used to estimate the seismic moment, slip displacement on the fault plane, and fault rupture length and width. Tide gauge readings were used to compare with these computer simulations. In general, the predicted arrival time of tsunami appears earlier than the actual tide record, and the run-up is higher than that of the record, except at certain locations.