Publication Date:
2017-04-04
Description:
The attenuation of seismic waves is one of the basic physical parameters used in seismological studies and earthquake
engineering, which is closely related to the seismicity and regional tectonic activity of a particular area. In this work, the seismic
attenuation in the Straits of Messina, affected by several and strong historical earthquakes, was studied using waveforms recorded
by a local seismic network composed of seven stations. We measured: the coda quality factor (Qc) in the Single Scattering model
hypothesis; the direct quality factor (Qd) applying the Coda Normalization method for S-waves; and the intrinsic and scattering
quality factor (Qi and Qs) by the Multiple Lapse Time Window Analysis (MLTWA) method. Coda Q values were obtained using
different lapse times (40, 60 and 80 s) for the frequency bands centred at 1.5, 3, 6 and 12 Hz. Our findings indicate that Qc increases
with increasing lapse time and that Qc is frequency dependent. This behaviour is usually correlated to the degree of tectonic
complexity and to the presence of heterogeneities at several scales. In fact, by using the Coda Normalization method we obtained
low Qd values, as expected for a heterogeneous and active zone.
Finally, by the MLTWA method we observe that the contribution of the scattering attenuation (Qs
−1) prevails on the intrinsic
absorption (Qi
−1) until 3 Hz. Conversely, Qi
−1 and Qs
−1 seem to be of the same order in the higher frequency bands.
Description:
Published
Description:
173-185
Description:
reserved
Keywords:
Coda waves
;
Intrinsic attenuation
;
S-waves
;
Scattering attenuation
;
Straits of Messina
;
04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Format:
897169 bytes
Format:
application/pdf
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