Seismic waves from atomic bomb tests

Registration of seismic waves from atomic bombs provides a direct check on accepted travel-time curves. The Baker Day test at Bikini on July 24, 1946, U.T., was recorded at eight stations by short-period Benioff vertical-component seismometers. Only longitudinal waves (P) appear; no transverse waves or surface waves have been found. Figure 1 shows the seismogram at Mount Wilson; the others are similar.