Paul W. Pomeroy

Excitation of Surface Waves by Events in Southern Algeria

Surface-wave magnitudes (M8) of 4.1 and 3.2 are determined for two events in southern Algeria. The corresponding body-wave magnitudes (mb) are 5.8 and 4.9, respectively. The surface waves from these events are much smaller than would be expected from most earthquakes of comparable body-wave magnitudes, which fact suggests that these waves were generated by underground explosions.

Long-Period Seismic Waves from Nuclear Explosions in Various Environments

Large nuclear explosions in the solid earth, the hydrosphere, and the lower and upper atmosphere have generated seismic waves of periods greater than about 5 seconds which have been detected at great distances from the source.

Wake Island hydrophone seismic array

The hydrophone array installed near Wake Island (WHA) was reactivated as a seismic station in June 1979 by the Hawaii Institute of Geophysics. WHA consists of six bottom phones, at 5.5‐km depth, in an array 40 km across and an additional four pairs of phones, at large spacing, suspended at SOFAR depth. The bottom array lies in a flat area on high Q lithosphere > 108 years old. All of the deep and five of the SOFAR phones are operational. Until September 1982, generally data were recorded from only three phones, on a slow speed analog cassette recorder. The station is now being upgraded for digital recording of all 11 phones. Many circumpacific earthquakes and nuclear tests have been well recorded by WHA, its location being ideally suited for monitoring such events. Nearly pure oceanic paths between WHA and circumpacific sources facilitate studies of the ocean‐lithosphere waveguide such as propagation and attenuation of high‐frequency, teleseismic Pn and Sn. For frequencies above 3 Hz, WHA is quieter than ...