速度・状態依存摩擦則を用いた地震サイクル計算におけるdip angleおよび動的応力伝播の効果

抄録

Numerical model of long-term fault slip (earthquake cycle) simulation had been initially developed with a 90-degree dip angle to the free surface, neglecting dynamic stress transfer. At present we can implement either effect of lower dip angle or the dynamic stress transfer into the model, but mounting both effects is still difficult. Here we perform numerical experiments of the earthquake cycle model to compare the dip-angle effect with the dynamic effect. Qualitatively, both prolong earthquake recurrence interval by enlarging event magnitude. We find that the effect of the low dip angle can be greater than the dynamic stress transfer when the dip angle is as small as actual subduction plate interface. This tendency is stronger as seismic area is shallower.