Ocean bottom microseisms from a distant supertyphoon

In this paper we describe microseisms and swell produced by a supertyphoon in the western Pacific, near the Philippine Islands, recorded from an ocean‐bottom seismic ‘station’ (OBSS) located about 200 km west of San Francisco, California at a depth of about 4 km and from a pressure sensor installed in shallow water near Pt. Arena, California. The microseisms recorded on OBSS are generated by the swell in the vicinity of the station and narrow‐band spectral peaks observed with frequency increasing slowly with time from the ocean‐wave dispersion correlate well, at twice the frequency, with swell near Pt. Arena. Similar, previously reported, observations at OBSS from storms in the northeastern Pacific are consistent with fundamental Rayleigh wave propagation, toward the coast in that case and away in the present, possibly related to a large difference in the estimated width of the zone of interaction between incident and reflected swell along the California coast.