EMPIRICAL RELATION OF EFFECTIVE STRESS ON ASPERITY TO FAULT TYPE AND DEPTH INFERRED FROM EXISTING SPECTRUM INVERSION RESULTS AND SOURCE INVERSION RESULTS

Empirical relations of the effective stress on the asperity to the fault type and the depth were examined for more accurate prediction of strong ground motions from a future earthquake. The existing spectrum inversion results showed that the level of the acceleration source spectrum in a short period range, called short period level in this paper, varied several hundred percent as a function of the fault type (inland earthquake, subduction earthquake, and slab earthquake) and 10 percent as a function of the focal depth. The effective stress on the asperity, inferred from the short period level, had the same feature as the short period level. The existing variable-slip rupture models showed that the effective stress on the subfaults in the asperity varied several hundred percent as a function of the fault type (strike slip fault with a surface rupture, reverse fault with a buried rupture, and oblique slip fault with a buried rupture) and 10 to 30 percent as a function of the depth of the subfault.