Abstract
Three hundreds of fault rupture scenarios considering uncertainties are generated for both strike slip and reverse faults with magnitude around Mw 6.6, in this paper. Ground motions are simulated by stochastic Green's function method at 10,201 sites in 200 km x 200km area with 2km grids. Very simple distribution of average ground motion is derived from the results, however, distribution of variation coefficent is rather complex but accountable from radiation pattern and forward directivity effect.
Applying fault rupture model on PSHA, it is expected to get over an intrinsic problems of general PSHA based on empirical attenuation formulae. The formulae are based on data set of observed ground motions at various sites due to limited number of earthquakes; i.e. spatial variation, although required design basis ground motions should be defined at a target site from an assuming source fault with uncertainties of repeating fault ruptures; i.e. temporal variartion. In probabilistic earthquake hazard analysis, this problem is supplemented by ergodic property. Using the calculated data sets above, ergodic property of uncertainties are examinned. Through the study, it is assumed that temporal variations are remarkably smaller than spatial variations. The results encourage future study for reducing variations of strong ground motions used in probabilistic analysis.
