Bayesian Estimation of Seismic Hazard for Two Sites in Switzerland

Authors: RÜTTENER E.¹; EGOZCUE J.J.²; MAYER-ROSA D.¹; MUELLER S.¹

Source: Natural Hazards, Volume 14, Numbers 2-3, 1996 , pp. 165-178(14)

Publisher: Springer

Abstract:

Seismic hazard analysis is based on data and models, which both are imprecise and uncertain. Especially the interpretation of historical information into earthquake parameters, e.g. earthquake size and location, yields ambiguous and imprecise data. Models based on probability distributions have been developed in order to quantify and represent these uncertainties. Nevertheless, the majority of the procedures applied in seismic hazard assessment do not take into account these uncertainties, nor do they show the variance of the results. Therefore, a procedure based on Bayesian statistics was developed to estimate return periods for different ground motion intensities (MSK scale).

Bayesian techniques provide a mathematical model to estimate the distribution of random variables in presence of uncertainties. The developed method estimates the probability distribution of the number of occurrences in a Poisson process described by the parameter . The input data are the historical occurrences of intensities for a particular site, represented by a discrete probability distribution for each earthquake. The calculation of these historical occurrences requires a careful preparation of all input parameters, i.e. a modelling of their uncertainties. The obtained results show that the variance of the recurrence rate is smaller in regions with higher seismic activity than in less active regions. It can also be demonstrated that long return periods cannot be estimated with confidence, because the time period of observation is too short. This indicates that the long return periods obtained by seismic source methods only reflects the delineated seismic sources and the chosen earthquake size distribution law.

Keywords: historical earthquakes; seismic hazard; Bayesian estimation; data uncertainty; probability distribution; macroseismic intensity

Language: English

Document Type: Regular paper

Affiliations: 1: Swiss Seismological Service, Institute of Geophysics, ETH-Hönggerberg, CH-8093 Zurich, Switzerland 2: Universidad Politécnica de Cataluna, Dep. Matématica Aplicada III, Gran Capitán s/n, E-08034 Barcelona, Spain

Publication date: 1996-01-01

• In this: publication
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• In this Subject: Geography ,  Geology ,  Social & Public Welfare
• By this author: RÜTTENER E. ;  EGOZCUE J.J. ;  MAYER-ROSA D. ;  MUELLER S.

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