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The use of body-wave spectra in the determination of seismic-source parameters

Hanks, Thomas C. and Wyss, Max (1972) The use of body-wave spectra in the determination of seismic-source parameters. Bulletin of the Seismological Society of America, 62 (2). pp. 561-589. ISSN 0037-1106.

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Teleseismic determinations of body-wave (P, S) spectra, interpreted in terms of the Brune (1970) seismic-source model, are used to estimate the parameters seismic moment (M_o) and source dimension (r) for three large, shallow, strike-slip earthquakes occurring on nearly vertical fault planes and for which the same parameters can be determined from field (F) data. These earthquakes are (1) the Borrego Mountain, California, earthquake (April 9, 1968) for which [M̅_o(P) = 10, M̅_o(S) = 6.6, and M_o(F) = 3.6] × 10^(25) dyne-cm and [r̅(p) = 14, r̅(S) = 23, and L/2(F) = 17] km; (2) the Mudurnu Valley, Turkey, earthquake (July 22, 1967) for which [M̅_o(P) = 9.1, M̅_o(S) = 8.5, and M_o(F) = 7.4] × 10^(26) dyne-cm, and [r̅(P) = 39, r̅(S) = 48, and L/2(F) = 40] km; and (3) the Dasht-e-Bayāz, Iran, earthquake (August 31, 1968) for which [M̅_o(P) = 4.8, M̅_o(S) = 8.6, and M_o(F) = 18] × 10^(26) dyne-cm, and [r̅(P) = S1, r̅(S) = 48, and L/2(F) = 40] km. The Brune (1970) model is well-calibrated with respect to the determination of these parameters for the earthquakes considered. A minimum estimate for the radiated energy can be expressed in terms of M_o and r; this estimate is low by a factor of 10 with respect to the estimate obtained from energy-magnitude relations for these three earthquakes. The stress drops of these events are of the order of 10 bars.

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Additional Information:Copyright © 1972, by the Seismological Society of America. Manuscript received August 9, 1971. This work was supported by NSF Grant Ga-12868 (Earthquake Mechanisms), by the Advanced Research Projects Agency under the Air Force Office of Scientific Research Contracts AF 44620-69-C-0067 and AF 19628-71-C-0245, and by the U.S. Geological Survey Contract 14-08-0001-12289 under ARPA Order No. 1684. John Kuo, Keith McCamy, Otto Nuttli, and Lynn Sykes read the manuscript and provided several pertinent comments. We benefited from discussions with James Savage concerning the directivity function. Peter Molnar and Mihailo Trifunac pointed out the error associated with the asymptotic approximation in the radiated energy integral.
Funding AgencyGrant Number
Advanced Research Projects Agency (ARPA)1684
Air Force Office of Scientific Research (AFOSR)AF 44620-69-C-0067
Air Force Office of Scientific Research (AFOSR)AF 19628-71-C-0245
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Caltech Division of Geological and Planetary Sciences2051
Lamont-Doherty Geological Observatory1756
Issue or Number:2
Record Number:CaltechAUTHORS:20140812-155534880
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48452
Deposited By: George Porter
Deposited On:13 Aug 2014 14:03
Last Modified:03 Oct 2019 07:04

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