Publication Date:
2017-04-04
Description:
Strong ground motion attenuation relationships are fundamental tools for seismic hazard
evaluation. In Italy the most widely used attenuation relationship is the Sabetta and
Pugliese (1987 and 1996, here afters referred to as SP96) for evaluating peak ground
acceleration, peak ground velocity, Arias intensity and pseudovelocity response spectra,
of the Italian territory. The equation has been derived using 95 records relative to
17 earthquakes with magnitude ranging from 4.6 to 6.8. The SP96 relation is based
on the strongest events since the installation of accelerometric instruments in Italy,
dated 1972, such as Friuli 1976, Valnerina 1979, Irpinia 1980, and Lazio-Abruzzo
1984, which is the most recent event. In the time span 1984 – 2007 other moderate
seismic events occurred in Italy, namely the East Sicily 1991, Umbria-Marche 1997-
1998, Pollino 1998 and Molise 2002, with moment magnitude 〉 5, and huge data
sets have been obtained due to the installation of many temporary stations and digital
instruments. The Umbria-Marche and Molise accelerometric data sets allowed the calculation
of regional attenuation relationships that show a considerably different trend
compared to the SP96. In this time span a project for an updated Italian accelerometric
data base construction has been started with the aim of collecting all the acceleration
time histories recorded since 1972 and re-evaluating, updating and improving event
parameters, data processing and station geological/geotechnical characteristics.
The aim of this research is the implementation of a new weighted regression analysis with the expanded and updated database, including coefficients to model the
magnitude-dependent decay rate, the faulting mechanism, the local site effects and
the magnitude-dependent variance. In addition, the fit of the SP96 equation to the new
accelerometric data set spanning from 1972 to 2004 is evaluated with the aid of different
statistic techniques, in order to verify the need of deriving a new attenuation
equation.
Description:
Published
Description:
Vienna
Description:
3T. Pericolosità sismica e contributo alla definizione del rischio
Description:
open
Keywords:
attenuation relationship italian accelerometric data
;
04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Conference paper
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