engleski

Intrinsic and scattering attenuation of high- frequency S-waves in the central part of the External Dinarides

This study provides novel information about the attenuation properties of the crust beneath the central part of the External Dinarides (CED). This is geologically and tectonically complex region formed in the collision between the Adriatic microplate and the European plate. Contributions of intrinsic and scattering attenuation to total attenuation were calculated for the first time. MLTWA method, based on assumption of multiple isotropic scattering in a homogeneous medium with uniformly distributed scatterers, was applied to seismograms of 750 earthquakes recorded at 7 seismic stations. Selected events have hypocentral distances between 40 and 100 km with local magnitudes between 1.5 and 5.9. The analysis was performed over 11 frequency bands with central frequencies between 1.5 and 16 Hz. Results show that the seismic albedo of the studied area is less than 0.5 and suggest that the intrinsic attenuation dominates over scattering attenuation at all central frequencies and for all stations. In addition, we calculated total S-wave and expected coda wave attenuation for CED and compared them to the ones observed in previous studies by the coda normalization and the coda-Q method. All estimated attenuation factors decrease with increasing frequency. Obtained results are consistent with the ones from different studies in the area of central and east Mediterranean: the intrinsic attenuation for CED is among the highest and the scattering attenuation is close to the average value observed elsewhere.

intrinsic attenuation ; scattering attenuation ; coda waves ; MLTWA method ; the External Dinarides

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