engleski

INTRINSIC AND SCATTERING ATTENUATION OF HIGH-FREQUENCY S-WAVES IN THE SOUTHERN PART OF THE EXTERNAL DINARIDES

The southern part of the External Dinarides (SED) is a geologically and tectonically complex region formed in the collision between the Adriatic microplate and the European plate. The area is characterised by moderate to high seismicity with the rare occurrence of strong earthquakes. Previous studies on coda and direct body waves attenuation for the area suggest highly attenuating crust. In order to estimate the contributions of the intrinsic and the scattering attenuation (1/Qi and 1/Qsc) to the total S-wave attenuation, we applied the multiple lapse-time window analysis (MLTWA method). The method is based on the assumptions of multiple isotropic scattering in a homogeneous medium with uniformly distributed scatterers. We analysed events with hypocentral distances between 20 and 90 km and local magnitudes greater than 2.0 recorded on the broadband stations of Croatian Seismological Network in the SED area. Results show seismic albedo less than 0.5, as well as 1/Qi > 1/Qsc, therefore implying the intrinsic attenuation as the dominant process of S-waves energy loss in the study area. The results are very similar to the ones obtained for the northern and especially for the central part of the External Dinarides.

External Dinarides ; seismicity ; MLTWA method ; intrinsic and the scattering attenuation

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