Use of Long-Period Seismic Waves for Rapid Evaluation of Tsunami Potential of Large Earthquakes

Abstract

Two seismological methods for rapid evaluation of tsunami potential of an earthquake are discussed. In the first method, long-period (200 to 300 sec) surface waves are used to determine the seismic moment and the fault geometry. This method allows determination of the source parameters in about 10 minutes after the surface-wave data have been retrieved, and is appropriate for far-field tsunami warning purposes. In the second method, long-period (100 to 300sec) near-field displacements are used to estimate the seismic moment. Our numerical experiment for a source-station geometry appropriate for Japan demonstrates that a very rapid and robust method can be developed for near-field tsunami warning purposes, if an appropriate (long-period, low gain) recording system is available.

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