Publication Date:
2017-04-04
Description:
The coda normalization method is one of the most used methods in the inference of attenuation
parameters Qα and Qβ . Since, in this method, the geometrical spreading exponent γ is an
unknown model parameter, the most part of studies assumes a fixed γ , generally equal to
1. However γ and Q could be also jointly inferred from the non-linear inversion of codanormalized
logarithms of amplitudes, but the trade-off between γ and Q could give rise to
unreasonable values of these parameters. To minimize the trade-off between γ and Q, an
inversion method based on a parabolic expression of the coda-normalization equation has
been developed. The method has been applied to the waveforms recorded during the 1997
Umbria-Marche seismic crisis. The Akaike criterion has been used to compare results of the
parabolic model with those of the linear model, corresponding to γ = 1. A small deviation
from the spherical geometrical spreading has been inferred, but this is accompanied by a
significant variation of Qα and Qβ values. For almost all the considered stations, Qα smaller
than Qβ has been inferred, confirming that seismic attenuation, in the Umbria-Marche region,
is controlled by crustal pore fluids.
Description:
Published
Description:
1726-1731
Description:
3.1. Fisica dei terremoti
Description:
JCR Journal
Description:
restricted
Keywords:
Seismic attenuation
;
coda normalization method
;
04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
