Hazan: a FORTRAN program to evaluate seismic-hazard parameters using Gumbel's theory of extreme value statistics

Abstract

A FORTRAN IV computer program for seismic Hazard Analysis is presented and illustrated by an example. It evaluates the parameters of Gumbel's first and third type asymptotic distributions of extreme values and in the latter situation it is based on the nonlinear least-squares method developed by Marquardt. The application of this method is developed here so that the uncertainty on each parameter of Gumbel's third distribution is estimated and the complete covariance matrix is obtained, in recognition of the importance of assigning uncertainties to all parameters used for seismic hazard assessment. The primary data required is a chronological catalogue of earthquake magnitudes, however, earthquake magnitude or a related value of earthquake caused ground acceleration, velocity, or displacement may be the quantity used in the ensuing analysis to characterize the seismic hazard.