Sound Waves in the Atmosphere Generated by a Small Earthquake

In previous papers theoretical and experimental results on the coupling of atmospheric compressional waves to various types of surface waves in the underlying earth or ocean have been presented. Recently Benioff presented a paper describing a remarkable instance of atmospheric waves received at Pasadena from the earthquake of January 24, 1951, 07-17-01, magnitude 5.6, 33° 07'N., 115° 34'W., Δ = 265 km. The microbarograph recorded a train of waves which commenced gradually at about 23:34:00 P.S.T. with periods of about 3/4 second and ended at about 23:39:00 P.S.T. with periods of about 1 sec. (Fig. 1). Benioff had noticed a similar disburbance following a small tremor several years earlier.