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Analysis of T-phases recorded from recent tsunamogenic earthquakes indicates that they contain significantly more high-frequency (>50 Hz) relative to low-frequency (>10 Hz) T-phase energy with longer durations (>30 s) than nontsunamogenic events. Modeling T-phase spectrum explains this observation, where the spectrum of the recorded T-phase is the product of the source spectrum, propagation loss in the solid earth, conversion from seismic to acoustic T-phase energy, propagation loss in the ocean, and the instrument response. The propagation loss in the ocean can be accurately modeled. Assuming the seismic-to-acoustic conversion is constant over frequency, the remaining unknown term is loss in the solid earth which is primarily due to anelastic attenuation. A refined depth estimate can be obtained by modeling the solid-earth attenuation. That, coupled with the earthquake source mechanism, allows for estimation of the static ocean floor deformation and thus tsunami height. This approach has been applied to two tsunamogenic earthquakes (26, Dec. 2004, 28, Mar. 2005), and one other event. Both tsunamogenic events had significant (>1 m) seafloor uplift. In addition, the peak static offset estimated for the 26 Dec. event is consistent with estimates both from other studies, and from observations of the seafloor deformation.

Inversion of long‐period, teleseismic body waves for the Loma Prieta earthquake yields a nearly double‐couple moment tensor corresponding to an oblique mechanism with strike 130°, dip 73° and rake 146°. The long‐period centroid depth of the source is 18 km, and the seismic moment is 2.8×1019 Nm. The source time history consists of two pulses with a total duration of 8–9 sec. Preliminary forward modeling of broad‐band, teleseismic body waves indicates the occurrence of at least two sub‐sources. Constraining the fault orientation to the long‐period inversion result, the first source was located at 18 km depth, and the second source was located updip at about 14 km depth. The second source has a seismic moment 2.7 times that of the first, and occurred 2.0 sec after the first. The precise location of the second source will require further modeling.

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