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The energy release in earthquakes

Vassiliou, M. S. and Kanamori, Hiroo (1982) The energy release in earthquakes. Bulletin of the Seismological Society of America, 72 (2). pp. 371-387. ISSN 0037-1106.

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Energy calculations are generally made through an empirical application of the familiar Gutenberg-Richter energy-magnitude relationships. The precise physical significance of these relationships is somewhat uncertain. We make use here of the recent improvements in knowledge about the earthquake source to place energy measurements on a sounder physical basis. For a simple trapezoidal far-field displacement source-time function with a ratio x of rise time to total duration T_0, the seismic energy E is proportional to [1/ x(1 - x)^2] M_0^2/T_0^3, where M_0 is seismic moment. As long as x is greater than 0.1 or so, the effect of rise time is not important. The dynamic energies thus calculated for shallow events are in reasonable agreement with the estimate E ≅ (5 × 10^(−5))M_0 based on elastostatic considerations. Deep events, despite their possibly different seismological character, yield dynamic energies which are compatible with a static prediction similar to that for shallow events. Studies of strong-motion velocity traces obtained near the sources of the 1971 San Fernando, 1966 Parkfield, and 1979 Imperial Valley earthquakes suggest that, even in the distance range of 1 to 5 km, most of the radiated energy is below 1 to 2 Hz in frequency. Far-field energy determinations using long-period WWSSN instruments are probably not in gross error despite their band-limited nature. The strong-motion record for the intermediate depth Bucharest earthquake of 1977 also suggests little teleseismic energy outside the pass-band of a long-period WWSSN instrument.

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Kanamori, Hiroo0000-0001-8219-9428
Additional Information:© 1982 Seismological Society of America. Manuscript received 2 June 1981. We thank Medhat Haroun, who was most helpful in providing us with the strong-motion data we needed. Discussions with Bernard Minster and Larry Ruff were helpful. We also thank Tom Heaton, Steve Hartzell, and Jeff Given for reading through the manuscript. This research was supported by the Earth Science Section, National Science Foundation, Grants EAR77-13641 and EAR78-11973.
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Caltech Division of Geological and Planetary Sciences3631
Issue or Number:2
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Official Citation:M. S. Vassiliou and Hiroo Kanamori The energy release in earthquakes Bulletin of the Seismological Society of America, April 1982, v. 72, p. 371-387
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54125
Deposited By: Tony Diaz
Deposited On:27 Jan 2015 17:14
Last Modified:09 Mar 2020 13:18

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