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On Seismic Hazard Scenarios Characterization: From the Intensity Virtual Distribution to the Historical Earthquake Size, through a Seismic Moment-Felt area relation
by
D. Termini
Osservatorio Sismologico, Università di Messina Via Osservatorio, 4 - 98121 Messina (Italy).
Coauthors: A. Teramo
The determination of the size of an historical earthquake, even through a reduced number of observed intensity points, represents a topic of relevant interest within the characterization of a seismic hazard scenario. The proposed procedure, starting with the modelling of macroseismic intensity distribution aims to define a correlation between the virtual intensity distribution of a given earthquake, source parameters and seismic moment deduced through a macroseismic approach. In this regard, the vectorial distribution of the observed intensity is modelled to characterize the intensity virtual distribution through ellipses whose centres and semiaxes coincide with the calculated epicenter and the directions of the minimum and maximum intensity attenuation respectively. Given that the felt area of the earthquake, characterised by a set of such ellipses to which an intensity level is associated from IV MCS up to a Io epicentral intensity, the determination of the seismic moment is effected through an empirical relation based on the same felt area. The obtained results show the applicability of the proposed procedure to depict seismic hazard scenarios based on a felt-area and seismic moment values consistent with those taken from literature, even in the cases where show a lack of a suitable number of observed intensity points, where it is possible to correlate the felt-area of the earthquake to the tectonic and geomorphological characteristics of the seismogenic zone within which the given earthquake falls.
Date received: September 20, 2004
Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caon-60.