Computer Program for Seismic Hazard Analysis - A User Manual - (Stanford Seismic Hazard Analysis - STASHA)

When planning the design of a structure or a facility in a region of potential seismic activity, it becomes necessary to estimate the ground motion intensity to which the structure will be exposed during its economic life. The required information on the site intensity has to be derived using the seismic information available for the region, such as frequency of occurrence of earthquakes, Richter magnitude levels, etc.

Seismic Hazard Models are utilized to obtain the probabilities of the different ground intensity levels at a site. Therefore, the use of an established methodology to perform seismic hazard analysis and hence to synthesize the available seismological information for the purpose of ob­ training a reliable estimate of future seismic loading at a site is necessary.

The principal objective of the current work is that of describing a set of computer programs organized in a consistent way in order to be used to perform seismic hazard analysis at a specified geographic location.

The programs have been developed at Stanford University. They are based on probabilistic seismic risk models discussed in detail by Shah, Mortgat, and Kiremidjian (1975), and Mortgat (1978). They have been utilized for hazard mapping of Nicaragua, Costa Rica, Guatemala, Algeria, offshore Alaska, California, and Honduras (currently in progress) (1, 2, 3, 4, 7).*

The programs constitute a complementary set and are sufficient for the analysis. They are written in FORTRAN IV and have been tested on the Stanford IBM 370/168 computer. Certain programs, such as plotting and mapping routines, are system oriented and can be used only at the Stanford Computer Center.