Abstract
It has been argued that power-law time-to-failure fits for cumulative Benioff strain and an evolution in size-frequency statistics in the lead-up to large earthquakes are evidence that the crust behaves as a Critical Point (CP) system. If so, intermediate-term earthquake prediction is possible. However, this hypothesis has not been proven. If the crust does behave as a CP system, stress correlation lengths should grow in the lead-up to large events through the action of small to moderate ruptures and drop sharply once a large event occurs. However this evolution in stress correlation lengths cannot be observed directly. Here we show, using the lattice solid model to describe discontinuous elasto-dynamic systems subjected to shear and compression, that it is for possible correlation lengths to exhibit CP-type evolution. In the case of a granular system subjected to shear, this evolution occurs in the lead-up to the largest event and is accompanied by an increasing rate of moderate-sized events and power-law acceleration of Benioff strain release. In the case of an intact sample system subjected to compression, the evolution occurs only after a mature fracture system has developed. The results support the existence of a physical mechanism for intermediate-term earthquake forecasting and suggest this mechanism is fault-system dependent. This offers an explanation of why accelerating Benioff strain release is not observed prior to all large earthquakes. The results prove the existence of an underlying evolution in discontinuous elasto-dynamic systems which is capable of providing a basis for forecasting catastrophic failure and earthquakes.
| Original language | English |
|---|---|
| Pages (from-to) | 2413-2427 |
| Number of pages | 15 |
| Journal | Pure and Applied Geophysics |
| Volume | 159 |
| Issue number | 10 |
| DOIs | |
| State | Published - 2002 |
| Externally published | Yes |
Bibliographical note
Funding Information:This research was funded by the Australian Research Council and The University of Queensland. Computations were made on QUA KES’ 12 processor SGI Origin 2000 and the Australian Solid Earth Simulator (ASES) thematic parallel supercomputer facility (phase I – 16 processor SGI Origin 3800) funded by the ARC, The University of Queensland, CSIRO, University of Western Australia and Silicon Graphics. We express our appreciation to the reviewers whose helpful comments improved the manuscript, and to an anonymous reviewer for drawing our attention to the recent paper by ZOELLER et al., (2001).
Keywords
- Critical point hypothesis for earthquakes
- Earthquake prediction
- Lattice solid model
- Numerical simulation
- Stress correlation function evolution
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology
