Slip distribution of the 2003 Tokachi-oki earthquake estimated from tsunami waveform inversion

Abstract

The slip distribution of the 2003 Tokachi-oki earthquake is estimated from the 11 tsunami waveforms recorded at 9 tide gauges in the southern Hokkaido and eastern Tohoku coasts and two ocean bottom tsunami-meters (pressure gauges) off Kamaishi, Tohoku. The largest slip of 4.3 m is estimated on the subfault located off Hiroo. A large slip of 2.1 m is also estimated on the subfault located near Kushiro. The total seismic moment of the 2003 Tokachi-oki earthquake is 1.0 × 1021 Nm. The slip distribution estimated from the tsunami waveform inversion is similar to the slip distribution deduced by Yamanaka and Kikuchi (2003) from the inversion of the teleseismic body waves. The rupture area of the 2003 Tokachi-oki earthquake is similar to the western part of the rupture area of the 1952 Tokachi-oki earthquake estimated by Hirata et al. (2003).