Size of earthquakes in southern Mexico from indirect methods     

José A. Canas 《Pure and Applied Geophysics》1991,136(4):479-498

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Seismic attenuation in Iberia using the coda-Q method     

G. Payo  J. Badal  J. A. Canas  V. Corchete  L. Pujades  F. J. Serón 《Geophysical Journal International》1990,103(1):135-145

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Lateral variation and frequency dependence of coda-Q in the southern part of Iberia     

José A. Canas  Lluis Pujades  José Badal  Gonzalo Payo  Fernando de  Miguel  Francisco Vidal  Gerardo Alguacil  Jesús Ibañez  José Morales 《Geophysical Journal International》1991,107(1):57-66

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A method based on the coda attenuation law: Q = Q ₀( f/f ₀)^v leads to the determination of the lateral variation of coda- Q in the southern part of the Iberian Peninsula using seismograms belonging to the seismological network of the Cartuja Observatory, located in Granada. The lateral variation of Q ₀ ( Q value corresponding to a reference frequency f ₀ of 1 Hz) and its frequency dependence for the 1 to 5 Hz frequency range are, in general, in agreement with coda- Q values for frequencies less than about 1 Hz, previously determined in the region under study.
To determine the coda- Q values analytical functions have been used to fit the magnification curves of the vertical component short-period seismographs belonging to the Cartuja network. The problem is solved by using least-squares techniques and non-linear inversion. The determined coda- Q ₀ values and its frequency dependence correlate well with several known geophysical parameters in the southern part of the Iberian Peninsula.  相似文献   

Attenuation in Southeastern Sicily (Italy) by applying different coda methods     

E. Giampiccolo  G. Tusa  H. Langer  S. Gresta 《Journal of Seismology》2002,6(4):487-501

The attenuation in Southeastern Sicily has been investigated using 40aftershocks of the December 13 1990, earthquake. The quality factor ofcoda waves (Q_c) was estimated in the frequency range 1.5–24 Hz,applying three different methods in time and frequency domains. On thewhole, a clear dependence of Q_c on frequency was observed,according to the general law Q = Q₀(f/f₀)ⁿ . Thefrequency dependence relationships obtained from the analysis of codawaves at three lapse time windows (10, 20 and 30 seconds) show that, forall methods, Q₀ (Q_c at 1 Hz) significantly increases with lapsetime. In particular, Q₀ is approximately 20 at short lapse time (10s) and increases to about 70 at longer lapse time (30 s). This is attributedto the fact that larger lapse times involve deeper parts of the crust andupper lithosphere which may be characterized by larger quality factors.Moreover, the value of the exponent n decreases with increasing codalengths from about 1.3 to 0.9, suggesting a decrease in heterogeneity ofthe medium with depth.Finally, Q_c-values here found are of the same order as thosereported from other tectonic regions like the Anatolian Highlands orSouthern Spain, while significantly higher than in the neighboring volcanicarea of Mt. Etna.  相似文献