Appraisal of seismic hazard parameters for the seismic regions of the east circum-pacific belt inferred from a bayesian approach

摘要

The assessment of seismic hazard parameters is important in the seismically active regions. A straightforward approach is considered for the statistical estimation of the maximum values of earthquake hazard parameters. The Bayesian estimator is suggested and emphasis is given to the evaluation of the maximum possible M_(max) (regional) magnitude in a future time interval T. This approach allows the uncertainty of earthquake magnitude to be accounted for. Seismic hazard parameters like the beta-value which is the slope of the magnitude-frequency law (where, b = log_e beta) and the intensity (rate) lambda of seismic activity and their uncertainties are also estimated. The quantiles of functions of distributions of true and apparent magnitude on a given time interval [O, T] are evaluated, as well. Two main assumptions are adopted for the method: (1) earthquake occurrence is Poissonian and (2) the magnitude-frequency law is of Gutenberg-Richter type with a cutoff maximum value of magnitude. It is needless to say the seismic catalog used must have a large number of events. This requirement leads to the estimation of the parameters referred to some of the most seismically active regions of the world, e.g., Chile. Peru-Equador-South Colombia, Central America and Mexico, which belong to the east part of the circum-Pacific belt.