Abstract
Predictions of earthquakes that are based on observations of precursory seismicity cannot depend on the average properties of the seismicity, such as the Gutenberg-Richter (G-R) distribution. Instead it must depend on the fluctuations in seismicity. We summarize the observational data of the fluctuations of seismicity in space, in time, and in a coupled space-time regime over the past 60 yr in Southern California, to provide a basis for determining whether these fluctuations are correlated with the times and locations of future strong earthquakes in an appropriate time- and space-scale. The simple extrapolation of the G-R distribution must lead to an overestimate of the risk due to large earthquakes. There may be two classes of earthquakes: the small earthquakes that satisfy the G-R law and the larger and large ones. Most observations of fluctuations of seismicity are of the rate of occurrence of smaller earthquakes. Large earthquakes are observed to be preceded by significant quiescence on the faults on which they occur and by an intensification of activity at distance. It is likely that the fluctuations are due to the nature of fractures on individual faults of the network of faults. There are significant inhomogeneities on these faults, which we assume will have an important influence on the nature of self-organization of seismicity. The principal source of the inhomogeneity on the large scale is the influence of geometry--i.e., of the nonplanarity of faults and the system of faults.
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Selected References
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- Christensen K, Olami Z, Bak P. Deterministic 1/f noise in nonconserative models of self-organized criticality. Phys Rev Lett. 1992 Apr 20;68(16):2417–2420. doi: 10.1103/PhysRevLett.68.2417. [DOI] [PubMed] [Google Scholar]
- Christensen K, Olami Z. Scaling, phase transitions, and nonuniversality in a self-organized critical cellular-automaton model. Phys Rev A. 1992 Aug 15;46(4):1829–1838. doi: 10.1103/physreva.46.1829. [DOI] [PubMed] [Google Scholar]
- Knopoff L. The organization of seismicity on fault networks. Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):3830–3837. doi: 10.1073/pnas.93.9.3830. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nakanishi H. Cellular-automaton model of earthquakes with deterministic dynamics. Phys Rev A. 1990 Jun 15;41(12):7086–7089. doi: 10.1103/physreva.41.7086. [DOI] [PubMed] [Google Scholar]
- Nakanishi H. Statistical properties of the cellular-automaton model for earthquakes. Phys Rev A. 1991 Jun 15;43(12):6613–6621. doi: 10.1103/physreva.43.6613. [DOI] [PubMed] [Google Scholar]
- Olami Z, Feder HJ, Christensen K. Self-organized criticality in a continuous, nonconservative cellular automaton modeling earthquakes. Phys Rev Lett. 1992 Feb 24;68(8):1244–1247. doi: 10.1103/PhysRevLett.68.1244. [DOI] [PubMed] [Google Scholar]
- Raleigh C. B., Sieh K., Sykes L. R., Anderson D. L. Forecasting southern california earthquakes. Science. 1982 Sep 17;217(4565):1097–1104. doi: 10.1126/science.217.4565.1097. [DOI] [PubMed] [Google Scholar]
- Sieh K., Jones L., Hauksson E., Hudnut K., Eberhart-Phillips D., Heaton T., Hough S., Hutton K., Kanamori H., Lilje A., Lindvall S., McGill S. F., Mori J., Rubin C., Spotila J. A., Stock J., Thio H. K., Treiman J., Wernicke B., Zachariasen J. Near-field investigations of the landers earthquake sequence, april to july 1992. Science. 1993 Apr 9;260(5105):171–176. doi: 10.1126/science.260.5105.171. [DOI] [PubMed] [Google Scholar]
- Sieh K. The repetition of large-earthquake ruptures. Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):3764–3771. doi: 10.1073/pnas.93.9.3764. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zoback M. D., Zoback M. L., Mount V. S., Suppe J., Eaton J. P., Healy J. H., Oppenheimer D., Reasenberg P., Jones L., Raleigh C. B., Wong I. G., Scotti O., Wentworth C. New evidence on the state of stress of the san andreas fault system. Science. 1987 Nov 20;238(4830):1105–1111. doi: 10.1126/science.238.4830.1105. [DOI] [PubMed] [Google Scholar]