Session III:
Physically-based simulation of earthquike generation and the earthquake cycle

2nd ACES (APEC Cooperation for Earthquake Simulation) Workshop in Japan



Simulation of Complex Recurrence Behavior of Earthquakes with an Interacting Fault System Model
Manabu Hashimoto


Abstract

Activity of large earthquakes in and around the Japanese Islands is simulated with a model that incorporates mechanical interactions between faults, including both interplate and intraplate faults. In this simulation, each fault element is assumed to accumulate stress with a constant slip deficit rate and redistribute its accumulated stress to surrounding faults by making a forward (coseismic) slip when the cumulative stress reaches an assumed threshold. The results from the inversion of geodetic data by Hashimoto and Jackson (1993) were used to specify slip deficit rates for these faults. Each fault in this model is divided into nine equal-sized elements, three in the length direction and three in the width direction, so that this model can simulate events as small as M6. The rate of stress accumulation is not necessarily constant for all faults, which may be attributed to the interaction between faults. It is interesting that fluctuations in the amplitude of stress changes with periods of about 2,000 years or longer are seen for some inland faults. Smaller events in which only one element on a fault ruptures frequently occur, but large events with three or more rupturing elements are rarely seen.

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