MEASUREMENTS OF INTRINSIC AND SCATTERING SEISMIC ATTENUATION IN THE CRUST

Intrinsic and scattering attenuation parameters, Q(i) and Q(s), have b een measured in three different tectonic areas for local and shallow e arthquakes located close to the receiver. The approach developed by We nnerberg (1993), which takes into account the numerical correction of the coda-Q parameter for the multiple scattering formulation of Zeng, was used to infer from the estimates of coda Q and direct S-wave Q the intrinsic (Q(i)) and scattering (Q(s)) Q values. Results for 1 to 12 Hz range show that Q(i) is comparable to Q(s) for the Etna volcano and for the Campi Flegrei area, while Q(i) for the tectonically active ar ea of Granada is lower than Q(s). Coda Q is close to intrinsic Q, sugg esting that, at least in the crust, coda Q is a good estimate of the i ntrinsic Q. Volcanic areas show a reasonable higher degree of heteroge neity, if compared with the nonvolcanic area of Granada.