Energetic and Enervated Earthquakes

Annemarie S. Baltay, Satoshi Ide, German A. Prieto, & Gregory C. Beroza

Published 2010, SCEC Contribution #1462

We apply the empirical Green's function coda-based seismic energy analysis of Baltay et al., 2010 to four earthquake sequences in Japan that span a magnitude range of 1.8 to 6.9. In addition to the seismic energy, we measure corner frequency and stress drop by fitting a Brune ω-2 spectrum to the spectra. We find no systematic dependence of apparent stress or stress drop on seismic moment for these sequences; however, we identify several anomalous events - both energetic and enervated - that show sharply different spectral signatures from the rest of the population. The existence of these events implies that much of the scatter in apparent stress and stress drop is real, and may have important implications for seismic hazard analysis.

Baltay, A. S., Ide, S., Prieto, G. A., & Beroza, G. C. (2010). Energetic and Enervated Earthquakes. Geophysical Research Letters,.