Publication Date:
2017-04-04
Description:
Scattered waves observed at the seismographs of the National Italy’s seismic network have
been used to investigate the intrinsic dissipation and scattering properties of the lithosphere
under the Southern Apennines, Italy. First, we investigate the coda-Q properties, then we apply
theMLTWanalysis in the hypothesis of velocity and scattering coefficient constant with depth,
and finally we interpret these results with the aid of numerical simulations in a medium with
depth dependent velocity and scattering coefficient.
Results obtained in the hypothesis of a uniform model show that a low scattering-Q−1 and a
relatively higher intrinsic-Q−1 characterize the lithosphere of the Southern Apennines. Numerical
simulations of the seismogram energy envelopes were performed hypothesizing a strongly
scattering crust and trasparent upper mantle, both with reasonable intrinsic dissipation coefficients.
In these symplifying assumptions the theoretical curves calculated for the homogeneous
model fit to the synthetic envelopes with scattering attenuation coefficients always greater than
the synthetic values. This results lead to the consideration that scattering-Q−1 obtained using
MLTW analysis under the assumption of uniform medium are overestimated. The values of
the scattering-Q−1 estimated for Apennines at low frequency (1–2 Hz) in the hypothesis of
uniform medium are of the same order of those obtained in several areas around the world.
The estimates obtained for frequencies ranging from 2 to 12 Hz are very low if compared
with those obtained in the same hypothesis for other areas around the world. Coda Q−1 closely
resembles intrinsic Q−1.
Description:
Published
Description:
10-22
Description:
3.1. Fisica dei terremoti
Description:
JCR Journal
Description:
reserved
Keywords:
absorption
;
scattering
;
seismic coda
;
04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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