Seismic energy release over a broad frequency band
- 48 Downloads
There remains much uncertainty on the absolute elastic wave energy released by fault rupture. Few direct estimates of the partition of seismic wave energy in ground shaking have been made. In this work, ground particle velocities from integrated accelerograms are used to compute the kinetic energy crossing unit area per unit time. Simplified theory for the near-field strong-motion case would appear to give a valid lower energy bound; the wave attenuation does not present a major problem. The partition of energy in predominantly P, S, and surface wave portions, for given frequency windows, is tabulated using strong-motion accelerograms recorded at different azimuths to the fault-sources of six California earthquakes (5.5<ML<7.2). Checks against earlier magnitudeML and momentM0 correlations indicate significantly higher overall wave energy outputs than expected, but further calibration is needed.
The study demonstrates that stable estimates of frequency-dependent seismic wave energies in the nearfield can be obtained from strong-motion records. Hence, energy flux may have a wider application to risk mapping than previously thought. In particular, a shift from peak acceleration scaling to (kinetic) energy inputs for engineering design appears to involve only routine processing.
Key wordsEarthquake energy accelerogram
Unable to display preview. Download preview PDF.
- Båth, M.,Earthquake energy and magnitude, InPhysics and Chemistry of the Earth, 7. (Pergamon Press, New York 1966), pp. 177–165.Google Scholar
- Berckhemer, H. andLindenfeld, M. (1985)Problems in calculating seismic wave energy from teleseismic signals. Int. Symp.,Physics of Fracturing and Seismic Energy Release. Liblice 1985, Abstract No. 3.Google Scholar
- Bullen, K. E. andBolt, B. A.,Introduction to the Theory of Seismology, Fourth Edition, (Cambridge University Press, Cambridge 1985), pp. 371–374.Google Scholar
- Gutenberg, B. andRichter, C. E. (1956),Magnitude and energy of earthquakes, Ann. di Geofis,9, 1–15.Google Scholar
- Jeffreys, H. (1923),The Pamir earthquake of 1911, February 18, in relation to the depths of foci. Mon. Not. R. Astro. Soc., Geophys. Suppl.1, 22–37.Google Scholar
- Thatcher, W. andHanks, T. C. (1973),Parameters of Southern California earthquakes. J. Geophys. Res.78, 8547–8576.Google Scholar
- Vassilioů M. S. andKanamori, H. (1982),The energy release in earthquakes. Bull. Seism. Soc. Am.72, 371–387.Google Scholar