Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1972 | Published
Journal Article Open

Seismic Source Descriptions of Underground Explosions and a Depth Discriminate


Synthetic seismograms of both body waves and Rayleigh waves are used to determine the radiation field of a few large contained underground explosions. A number of possible source descriptions are investigated. A reduced displacement potential of the form, ø(t) = ø_0t^ξ exp(-ηt), fits the long- and short-period data. The source parameters appropriate for the Boxcar event are ξ = 0·5 and η = 0·15. Synthetic PL and Rayleigh waves are compared with observations from a number of different size events to determine the dependence of η on yield. The amplitude of the long period synthetic body wave responses at ranges greater than about 12° increases rapidly as the source depth is increased. Thus the difference in spectral properties of explosions and earthquakes can be largely explained by the depth effect. The theoretical ratio SP/LP, that is the short period divided by the long-period amplitude, is computed from 12 to 25° for the Johnson upper mantle model and the Boxcar source. A study of an earthquake which cannot be distinguished from an explosion using the m_b vs. M_s criterion is investigated by the SP/LP discriminate.

Additional Information

© 1972 Royal Astronomical Society. Received in original form 1972 March 21. Received 1972 August 21. The authors were assisted by Gladys Engen and Shirley Fisher in the computations and digitization of seismograms. This research was supported by the Advanced Research Projects Agency of the Department of Defence and was monitored by the Air Force Office of Scientific Research under Contract Nos. F44620-69-C-0067 and F44620-70-C-0120.

Attached Files

Published - Harkrider_1973p45.pdf


Files (768.7 kB)
Name Size Download all
768.7 kB Preview Download

Additional details

August 19, 2023
October 25, 2023