Probability of earthquake occurrence as estimated from crustal strain

We illustrate how a simple statistical model can describe the quasiperiodic occurrence of large earthquakes. The model idealizes the loading of elastic energy in a seismic fault by the stochastic filling of a box. The emptying of the box after it is full is analogous to the generation of a large earthquake in which the fault relaxes after having been loaded to its failure threshold. The duration of the filling process is analogous to the seismic cycle, the time interval between two successive large earthquakes in a particular fault. The simplicity of the model enables us to derive the statistical distribution of its seismic cycle. We use this distribution to fit the series of earthquakes with magnitude around 6 that occurred at the Parkfield segment of the San Andreas fault in California. Using this fit, we estimate the probability of the next large earthquake at Parkfield and devise a simple forecasting strategy.

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“…The accumulated distribution of the box model in Eq. (15) for N = 11 with τ = 0.74 yr also is drawn. In Fig.…”

Section: Earthquake Probabilities At Parkfieldmentioning

confidence: 99%

The occupation of a box as a toy model for the seismic cycle of a fault

González

Gómez

Pacheco

2005

American Journal of Physics

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“…These are interpreted, in terms of plate tectonics, as the overriding plate margin dragged by the subducting PHS suddenly rebounds due to decoupling at the time of an earthquake (Fitch and Scholz, 1971;Ando, 1971Ando, , 1975aSavage, 1983). Long-term prediction programs for great interplate earthquakes in Japan are based on the strategy of detecting risky areas using this periodic interseismiccoseismic crustal deformation pattern (e.g., Rikitake, 1974;Mogi, 1985). For example, in the Tokai district in central Japan (Fig.…”

Section: Introductionmentioning

confidence: 99%

Intermediate-term precursors of great subduction zone earthquakes: An application for predicting the Tokai earthquake

Seno

2014

Earth Planet Sp

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The Philippine Sea coast of central-southwest Japan tilts oceanward during interseismic periods and peninsulas uplift suddenly at the time of great earthquakes. Tide gauge data indicate that precursory uplifts of the peninsulas occurred during about the decade prior to the occurrence of recent earthquakes. I construct a model to interpret the precursory uplifts on the basis of the model which assumes a fractal distribution of asperities. I calculate uplifts due to slow failures of smaller asperities contained in the rupture zone, assuming that the probability of breakage of the smallest unit asperity increases linearly over time. The time of breakage of one of the largest asperities is the time of the occurrence of a great earthquake, t f . I conduct a least squares fitting to the residual uplift data prior to great earthquakes to constrain t f . Applications to tide gauge data before the 1923 and 1946 earthquakes give t f = 1923.2 (±1.6), and 1943.7 (±2.7), respectively. For the expected Tokai earthquake, I obtain t f = 2007.6 (−5.4, +2.8) using precise leveling data. The intermediate-term precursors of a decade may be useful to limit the expected time of occurrence of coming great earthquakes, filling the gap between long-term and short-term earthquake predictions.

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“…We briefly outline the method here and refer the interested reader to appendix A for additional explanation. The approach used in this study is based upon a model of earthquake occurrence that assumes that the probability of an earthquake along a fault segment is initially low following a large segment-rupturing earthquake and increases with time as stress on the segment recovers the stress drop of the prior earthquake (Rikitake, 1974;Hagiwara, 1974). Fault segments expected to rupture in coming earthquakes are delineated using a variety of observations and judgments.…”

Section: Methodsmentioning

confidence: 99%