Tsunami Magnitude and Seismic Moment

Relation between tsunami magnitude m, (Imamura-Iida scale) and seismic moment M0, is investigated, using the data of 30 tsunamigenic earthquakes on the Pacific coast. The source area of tsunami is very well represented by the formula: log S=0.4m+3.3, where S is measured in square kilometers. The tsunami magnitudes m=1, 2, 3 and 4 correspond to the seismic moments of the order of M0=1027, 1028, 1029 and 1030 (dyne-cm), respectively. The tsunami magnitude due to the dip angle thrust faulting δ≥30° has a tendency to increase. It is useful information that the tsunami data be used a diagnostic aid in estimating seismic moment.