The Sound of Seismic - 3-D Seismic Survey

John N. Louie, 3 July 2001

The Sound of Seismic -- J. Louie's Research and Teaching -- Nevada Seismological Lab
This example illustrates an artificial, impulsive source of sonic energy - the thumper trucks used in seismic exploration for energy resources (courtesy of Optim LLC). Here each of the recordings made by 402 geophones covering a 10-square-km area are arranged according to distance from the thumper. You hear left-right pairs of 5-second records in sequence, sped up by a factor of 10 and with some quiet space inserted between records. All are from the same thumper source.

The close, initial records are clean and impulsive. As distance increases, the effects of wave propagation and near-sensor geologic complexity spread out the impulse and add reverberation. There is no noticeable shear wave as there is in the New Zealand earthquake record. The reverberations emphasize certain frequencies, just as in the Sand Mountain singing dune.

An additional echo appears occasionally, which is a reflection from the geothermal reservoir deep below.

MP3 file (1.6 Mb) Seismic arrivals in order of increasing distance from the source
Time increases downward in this plot:
The Sound of Seismic -- J. Louie's Research and Teaching -- Nevada Seismological Lab