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Upper crust attenuation in the Basin and Range Province of Sonora, Mexico
We estimated the S -wave quality factor Q ( f ) of the upper crust in northeastern Sonora, Mexico, using a two-layer model. The first layer of the model has a thickness of 1 km, and the frequency dependence of Q can be represented by the relation Q ( f ) = 127 f 0.7 in the frequency range of 0.5 ≤...
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Published in: | Journal of seismology 2021-10, Vol.25 (5), p.1241-1249 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | We estimated the
S
-wave quality factor
Q
(
f
) of the upper crust in northeastern Sonora, Mexico, using a two-layer model. The first layer of the model has a thickness of 1 km, and the frequency dependence of
Q
can be represented by the relation
Q
(
f
) = 127
f
0.7
in the frequency range of 0.5 ≤
f
≤ 20 Hz. The second layer varies in depth between 1 and 21 km, and
Q
(
f
) = 181
f
0.7
in the same frequency range. The average
Q
of the model, weighted with the thickness of the layers, gives the relation
Q
(
f
) = 179.1
f
0.7
. We used nonparametric attenuation functions, determined in a previous study, to correct the observed spectral amplitudes, and then we retrieved source and site effects using a spectral inversion scheme. We used the resulting functions to separate source and site effects from the original spectral records and modeled
Q
for the 1-D model’s depths. We analyzed 38 local earthquakes recorded by 12 stations of the regional network RESNES (
Red Sísmica del Noreste de Sonora
). We found that the
S
-wave
Q
of the superficial layer is a factor of only 1.4 smaller than the more profound layer. This result validates the use of an average
Q
to correct spectral amplitudes by the effect of anelastic attenuation from waves traveling within the upper crust. |
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ISSN: | 1383-4649 1573-157X |
DOI: | 10.1007/s10950-021-10025-0 |