Publication Date:
2017-04-04
Description:
Rapid evaluation of strong ground-shaking maps after moderate-to-large
earthquakes is crucial to recognizing those areas where the largest damage and losses
are expected. These maps play a fundamental role for emergency management. This is
particularly important for areas having high seismic risk potential and covered by
dense seismic networks. In near-real-time applications, ground-shaking maps are produced
by integrating recorded data and estimates obtained by using ground-motion
predictive equations, which assume point-source models. However, particularly for
large earthquakes, improvements in the predictions of the peak ground motion can
be obtained when fault extension and orientation are available. In fact, detailed source
information allows one to use a more robust source-to-site distance metric compared
with hypocentral distance.
In this paper, a technique for estimating both fault extent (in terms of its surface
projection) and dominant rupture direction is presented. This technique can be used in
near-real-time ground-motion map calculation codes with the aim of improving
ground-motion estimates with respect to a point-source model. The model parameters
are estimated by maximizing a probability density function based on the residuals
between observed and predicted peak-ground-motion quantities, the latter obtained
by using predictive equations. The model space to be investigated is defined through
a Bayesian approach, and it is explored by a grid-searching technique. The effectiveness
of the proposed technique is demonstrated by offline numerical tests using data
from three earthquakes occurring in different seismotectonic environments. The
selected earthquakes are the 17 August 1999 Mw 7.5 Kocaeli (Turkey) earthquake,
the 6 April 2009 Mw 6.3 L’Aquila (Italy) earthquake, and the 17 January 1994 Mw 6.7
Northridge (California) earthquake. The obtained results show that the proposed technique
allows for fast and first order estimates of the fault extent and dominant rupture
direction, which could be used to improve ground-shaking map calculations.
Description:
Published
Description:
661-679
Description:
4.1. Metodologie sismologiche per l'ingegneria sismica
Description:
JCR Journal
Description:
restricted
Keywords:
Source directivity
;
ShakeMap
;
L'Aquila earthquake
;
Northridge earthquake
;
Kocaeli earthquake
;
04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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