Analysis of seismological and tsunami data from the 1993 Guam earthquake
Abstract
The fault parameters of the Guam earthquake of August 8, 1993 are estimated from seismological analyses, and the possibility of identifying the actual fault plane from tsunami waveforms is tested. The Centroid Moment Tensor solution of longperiod surface waves shows one nodal plane shallowly dipping to the north and the other nodal plane steeply dipping to the south. The seismic moment is 3.5×10^{20} Nm and the corresponding moment magnitude is 7.7. The Moment Tensor Rate Function inversion of P waves also yields a similar focal mechanism and seismic moment. The point source depth is estimated as 40 50 km. This earthquake generated tsunamis that propagated toward the Japanese coast along the IzuBoninMariana ridge system. The tsunamis are recorded on ocean bottom pressure gauges and tide gauges. Numerical computation of tsunamis shows that the computed waveforms from the two possible fault planes match well with the observed tsunami waveforms. The numerical computation also shows that the tsunami waveforms at Guam Island, just above the fault, should contain useful information regarding the identification of the actual fault plane. However, the current sampling rate of the tide gauges is so small that the records cannot help the identification.
 Publication:

Pure and Applied Geophysics
 Pub Date:
 September 1995
 DOI:
 10.1007/BF00874396
 Bibcode:
 1995PApGe.144..823T
 Keywords:

 Tsunamis;
 the 1993 Guam earthquake;
 fault plane