Empirical relationship of T‐wave energy and fault parameters of northeast Pacific Ocean earthquakes

Abstract

A total of 179 northeast Pacific Ocean earthquakes that occurred between 1992–1998 are used to investigate the relationship of T‐wave acoustic energy and earthquake fault parameters. The moderate‐sized (3.7 ≤ Mw ≤ 6.9) earthquakes were recorded by ocean hydrophones and had their source parameters estimated by land‐based seismic networks. The acoustic energy release at the seafloor‐water interface of each earthquake was estimated by removing the signal attenuation along the propagation path and instrument gain from the hydrophone signal. There appears to be a relationship where, for a given magnitude earthquake, T‐wave energy is lower for normal and reverse fault earthquakes than strike‐slip events. A more detailed comparison indicates acoustic energy of the earthquake will often decrease as the component of dip‐slip motion increases. These observations suggest fault parameter information is contained within the T‐wave signal packet.