Abstract. Seismic-induced ground motion at a site is generally influenced by seismic source, propagation path and local site conditions. Over the last several decades, researchers have consistently asserted that for near site attenuation, the spectral parameter kappa is subject primarily to site conditions. In this research we estimated parameter kappa based on the acceleration amplitude spectrum of shear waves, from the selected recordings of local earthquakes from seismological stations situated in the western part of Croatia from the slope of the high-frequency part. The spatial distribution of individual kappa values is compared with the azimuthal distribution of earthquake epicentres, with Vs30 values and the published coda-Q values for each station, as well as with isoseismal maps for several stronger events in the investigated area, along with the geological features. The dextral shift of crustal segments and frontal thrust of the External Dinarides along the Kvarner fault zone has probably had an impact on the geometry of the kappa parameter contour lines. These results are important for gaining further insight into the attenuation of near-surface crust layers in the Northwestern External Dinarides and the associated Adriatic foreland, as well as in similar geotectonic settings.
Coda Q-1 in Awaji Island Estimated from the Aftershock Records of the 1995 Hyogo-ken Nanbu Earthquake.
