A year of microseisms in southern California

Peter Gerstoft, & Toshiro Tanimoto

Published October 2007, SCEC Contribution #1153

Microseisms are due to continuous harmonic forcing by ocean waves, whose sources vary in time, frequency, and azimuth. Using frequency-domain array beamforming, this variation is studied using one-year of continuous seismic data from 155 stations in southern California. Detailed analysis of data delineates spatiotemporal variations of sources for the primary and secondary microseisms. Both types of microseisms are generated near the coasts but the locations of excitation are different and change with season. Often sources are multiply located but can be spread out over wider areas, especially in the case of secondary microseisms. Distant storms can also be seen occasionally in the frequency range between the primary and secondary microseisms where spectral amplitudes from nearby sources are low.

Key Words
United States, California, Southern California Seismic Network, Southern California, time series analysis, statistical analysis, microseisms, magnitude, elastic waves, seismic waves, seismic networks, earthquakes

Gerstoft, P., & Tanimoto, T. (2007). A year of microseisms in southern California. Geophysical Research Letters, 34, L20304. doi: 10.1029/2007GL031091.