Институт вычислительной математики
и математической геофизики

Abstracts

Parallel numerical algorithms

Study of seismicity with the statistical and phenomenological analysis of the real earthquake catalogs has the disadvantage that the reliable data cover, in general, a time interval of about one hundred years or even less. This time interval is very short, in comparison with the duration of tectonic processes responsible for the seismic activity. Therefore the patterns of the earthquake occurrence identifiable in a real catalog may be only apparent and may not repeat in the future. In this connection, mathematical models of seismicity, i.e., of earthquake sequences, are important tools supplying synthetic catalogs, which may cover very long time interval that allows us to acquire a more reliable estimation of the parameters of seismic flow and to search for premonitory patterns preceding large events. It is evident that a model should be adequate in the sense of reproducing properties of observed seismicity (first of all, the Gutenberg-Richter law on frequency-magnitude relation, migration of events, seismic cycle and so on). Only in this case it is possible to use a synthetic catalog, being a result of numerical simulation, for obtaining some estimations of characteristics of an earthquake flow.

We consider the spherical block model, which is used to study dynamics of the global system of tectonic plates. This model requires a lot of computational burden that sometimes makes impossible to use it at a one-processor computer. However, the approach applied to modeling admits sufficiently effective parallelization of calculations at a multiprocessor machine. Namely this fact makes possible passing to simulation of dynamics and seismicity for the global system of tectonic plates using real geophysical and seismic data. The description of the parallel algorithm, corresponding program, and results of numerical simulation for different systems of tectonic plates are presented.

Two block structures are considered: the first is characterized by specifying the largest plates as boundary blocks, whereas the second is the closed spherical structure covering the whole surface of the Earth. Results of numerical experiments include the qualitative information on displacements of plates, and on the nature of their interaction along boundaries. Synthetic earthquake catalogs reveal some patterns of observed seismicity. The dependence of properties of the synthetic seismicity on the model parameters is analyzed. It turns out that the dynamics of the global system of tectonic plates is more accurately modeled by means of the closed block structure than with the structure for that boundary blocks are specified. In the report directions of future investigations are outlined.

Note. Abstracts are published in author's edition

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