Publication Date:
2017-04-04
Description:
The strong motion data of 2009 April 6 L’Aquila (Central Italy) earthquake (Mw = 6.3) and of
12 aftershocks (4.1 ≤ Mw ≤ 5.6) recorded by 56 stations of the Italian strong motion network
are spectrally analysed to estimate the source parameters, the seismic attenuation, and the site
amplification effects. The obtained source spectra for S wave have stress drop values ranging
from 2.4 to 16.8 MPa, being the stress drop of the main shock equal to 9.2 MPa. The spectral
curves describing the attenuation with distance show the presence of shoulders and bumps,
mainly around 50 and 150 km, as consequence of significant reflected and refracted arrivals
from crustal interfaces. The attenuation in the first 50 km is well described by a quality factor
equal to Q( f ) = 59 f 0.56 obtained by fixing the geometrical spreading exponent to 1. Finally,
the horizontal-to-vertical spectral ratio provides unreliable estimates of local site effects for
those stations showing large amplifications over the vertical component of motion.
Description:
Published
Description:
1573–1579
Description:
4.1. Metodologie sismologiche per l'ingegneria sismica
Description:
JCR Journal
Description:
open
Keywords:
Generalized inversion
;
strong-motion
;
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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