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Regional moments, energy levels, and a new discriminant

Zhao, Lian-She and Helmberger, Donald V. (1996) Regional moments, energy levels, and a new discriminant. Pure and Applied Geophysics, 146 (2). pp. 281-304. ISSN 0033-4553. doi:10.1007/BF00876494.

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Teleseismic observations of explosions tend to be richer in short-period energy than are earthquakes, thus the effectiveness of the m_b∶M_s discriminant. At regional distances the same basic separation occurs for smaller events in terms of M_L∶M_0 (Woodset al., 1993) and m_b∶M_0 (Patton and Walter, 1993). While these studies demonstrate the basic differences in excitation, they suffer in practical application because of the detailed information required in the retrieval of M_0. In this paper, we introduce a new method of discrimination, based on the energy strength (M_E) from broadband regional records that appears to be effective and efficient. In this method all events are processed as earthquakes, and explosions are distinguished by their stronger energy levels relative to their long-period amplitudes. Results from 29 events recorded by TERRAscope, sampling 15 explosions from NTS and 14 earthquakes from the southwestern United States, are represented, indicating complete separation (45 data points). M_L = 3.6 is the smallest event examined to date but the method can probably be extended to even smaller levels in calibrated regions.

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Additional Information:© 1996 Birkhäuser Verlag, Basel. Received April 25, 1995, accepted June 27, 1995. We thank Brad Woods, Craig Scrivner, Doug Dreger and Chandon Saikia for their reviews and useful discussion concerning models. We thank Brian Mitchell, the editor, and two anonymous reviewers for comments and suggestions. This research was supported partially by the Department of Defense and was monitored by the Air Force, Office of Scientific Research, under the contracts F49620-93-1- 0221 and F49620-94-0287. Contribution No. 1162 of Institute for Geophysics, the University of Texas at Austin.
Funding AgencyGrant Number
Department of Defense (DOD)UNSPECIFIED
Air Force Office of Scientific Research (AFOSR)F49620-93-1-0221
Air Force Office of Scientific Research (AFOSR)F49620-94-0287
Subject Keywords:Energy discriminant, magnitude, amplitude, earthquake, explosion
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Other Numbering System NameOther Numbering System ID
University of Texas Austin Institute for Geophysics1162
Issue or Number:2
Record Number:CaltechAUTHORS:20130305-083904557
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37292
Deposited By: Tony Diaz
Deposited On:05 Mar 2013 23:58
Last Modified:09 Nov 2021 23:28

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