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Application of an inhomogeneous stress (patch) model to complex subduction zone earthquakes: A discrete interaction matrix approach

Rundle, John B. and Kanamori, Hiroo (1987) Application of an inhomogeneous stress (patch) model to complex subduction zone earthquakes: A discrete interaction matrix approach. Journal of Geophysical Research B, 92 (B3). pp. 2606-2616. ISSN 0148-0227. doi:10.1029/JB092iB03p02606.

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In recent years it has been recognized that the level of shear and normal stress along a fault can vary; thus the stress is spatially and temporally inhomogeneous. Moreover, it has also been suspected that faults might interact in some way, with the result that a variety of earthquake magnitudes might be produced along a given length of fault at varying times. In order to explore these ideas we have developed a quantitative formalism, which we call the interaction matrix method, to express the influence of one fault upon another. This matrix is calculated by use of the energy change for a system of interacting cracks or faults and therefore gives energy-consistent results. Specifically, the interaction matrix relates the area-averaged stress on the fault segment to the area-averaged slip state on all the other fault segments in the system. Since any fault can be subdivided into an arbitrary number of fault segments, the interaction matrix can have arbitrary dimension; in fact, the continuum limit is recovered as the dimension of the matrix approaches infinity. We combine this matrix method with a segmentation, or “patch,” model for earthquakes, in which each discrete segment of a fault has the same coseismic stress change (defined as the difference between the driving stress at which healing occurs minus the driving stress at which sliding starts) each time it slips. We show that slip on a patch during an earthquake can vary substantially, depending on how it interacts with other nearby patches. In this model it is quite possible for the spatial distribution of stress on the fault following an event to be again in a spatially inhomogeneous state, rather than in a uniform state, as is often assumed. Hence the seismic moment produced by an earthquake on a given set of patches can vary substantially, depending on the sequence of sliding and healing on the different patches. To apply these ideas, we devised a means to calculate the interaction matrix elements and used them to quantitatively examine earthquake sequences off the Colombia-Ecuador coast and in the Nankai Trough near Japan.

Item Type:Article
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Kanamori, Hiroo0000-0001-8219-9428
Additional Information:Copyright 1987 by the American Geophysical Union. (Received April 21, 1986; revised December 1, 1986; accepted December 2, 1986.) Paper number 6B6036. The authors would like to acknowledge stimulating discussions with John Rudnicki and with Peter Malin. This research was supported by a grant from the National Aeronautics and Space Administration, Crustal Dynamics Program, to Sandia National Laboratories and by the U.S. Department of Energy under contract DE-AC04-76DP00789 to Sandia National Laboratories.
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Sandia National LaboratoriesUNSPECIFIED
Department of Energy (DOE)DE-AC04-76DP00789
Issue or Number:B3
Record Number:CaltechAUTHORS:20141030-085432935
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Official Citation:Rundle, J. B., and H. Kanamori (1987), Application of an inhomogeneous stress (patch) model to complex subduction zone earthquakes: A discrete interaction matrix approach, J. Geophys. Res., 92(B3), 2606–2616, doi:10.1029/JB092iB03p02606.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51045
Deposited By: George Porter
Deposited On:30 Oct 2014 16:57
Last Modified:10 Nov 2021 19:04

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