MEASUREMENTS OF INTRINSIC AND SCATTERING SEISMIC ATTENUATION IN THE CRUST

Abstract

Intrinsic and scattering attenuation parameters, Q~ and Qs, have been measured in three different tectonic areas for local and shallow earthquakes located close to the receiver. The approach developed by Wennerberg (1993), which takes into account the numerical correction of the coda-Q parameter for the multiple scat- tering formulation of Zeng, was used to infer from the estimates of coda Q and direct S-wave Q the intrinsic (Qi) and scattering (Qs) Q values. Results for 1 to 12 Hz range show that Q~ is comparable to Qs for the Etna volcano and for the Campi Flegrei area, while Qi for the tectonically active area of Granada is lower than Qs. Coda Q is close to intrinsic Q, suggesting that, at least in the crust, coda Q is a good estimate of the intrinsic Q. Volcanic areas show a reasonable higher degree of heterogeneity, if compared with the nonvolcanic area of Granada.