Publication Date:
2017-04-04
Description:
We present a physically based methodology to predict the range of ground-motion hazard
for earthquakes along specific faults or within specific source volumes, and we demonstrate
how to incorporate this methodology into probabilistic seismic hazard analyses (PSHA). By
‘physically based,’ we refer to ground-motion syntheses derived from physics and an understanding
of the earthquake process. This approach replaces the aleatory uncertainty that current
PSHA studies estimate by regression of empirical parameters with epistemic uncertainty that
is expressed by the variability in the physical parameters of the earthquake rupture. Epistemic
uncertainty can be reduced by further research.We modelled wave propagation with empirical
Green’s functions. We applied our methodology to the 1999 September 7 Mw = 6.0 Athens
earthquake for frequencies between 1 and 20 Hz.We developed constraints on rupture parameters
based on prior knowledge of the earthquake rupture process and on sources within the
region, and computed a sufficient number of scenario earthquakes to span the full variability of
ground motion possible for a magnitude Mw = 6.0 earthquake with our approach. We found
that: (1) our distribution of synthesized ground motions spans what actually occurred and that
the distribution is realistically narrow; (2) one of our source models generates records that
match observed time histories well; (3) certain combinations of rupture parameters produced
‘extreme,’ but not unrealistic ground motions at some stations; (4) the best-fitting rupture
models occur in the vicinity of 38.05!N, 23.60!Wwith a centre of rupture near a 12-km depth
and have nearly unilateral rupture toward the areas of high damage, which is consistent with
independent investigations.We synthesized ground motion in the areas of high damage where
strong motion records were not recorded from this earthquake. We also developed a demonstration
PSHA for a single magnitude earthquake and for a single source region near Athens.
We assumed an average return period of 1000 yr for this magnitude earthquake and synthesized
500 earthquakes distributed throughout the source zone, thereby having simulated a sample
catalogue of ground motion for a period of 500 000 yr. We then used the synthesized ground
motions rather than traditional attenuation relations for the PSHA.
Description:
This project was partially funded by the National
Observatory of Athens, Greece, which also contributed significant data and data processing. The University of Athens, Greece contributed significant computational facilities and data. This project was partially supported by the University of California, Lawrence Livermore National Laboratory under the auspices of the U.S. Department of Energy under contract W-7405-Eng-48.
Description:
Published
Description:
659-680
Description:
4.1. Metodologie sismologiche per l'ingegneria sismica
Description:
JCR Journal
Description:
reserved
Keywords:
computational PSHA
;
empirical Green's functions
;
quasi-dynamic
;
source models
;
strong ground-motion prediction
;
1999 Athens earthquake
;
04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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