ASSESSMENT OF SEISMIC HAZARD NEAR FAULTS OF UNCERTAIN TYPE - INTER-PLATE VERSUS INTRAPLATE

Maximum magnitude is an important input parameter in seismic hazard an alysis, but may be difficult to determine directly on the basis of ava ilable seismological data. Moreover, there is evidence that the scalin g law relating maximum magnitude to fault length for inter-plate fault s may differ from the law for intra-plate faults. Thus uncertainty as to the fault type can complicate the problem of determining maximum ma gnitude. We present a method for examining the implications for seismi c hazard analysis of uncertainty regarding fault type. We apply the me thod to a simple constructed example and find that the problem of asse ssing fault type can be far more critical to the hazard assessment tha n the exact statement of fault geometry, especially for sites that are distant from the fault.