SITE EFFECT ASSESSMENT OF SEISMOLOGICAL STATIONS OF ALBANIA THROUGH HVNR TECHNIQUE

摘要

In this paper is presented the study of site response parameters of Albanian Seismological Stations (ASN) from ambient noise measurements and felt earthquakes. The seismological stations of Albania which use the VSAT communication technology are located generally in hard rock formations. The aim of Methodology is to compare the response parameters of the sites (fundamental frequency, amplification) for registered seismic signals, from microtremors and the earthquakes as well. The predominant frequency of the site of every seismological station site is determined using the methodology of Horizontal to Vertical Spectral Ratio (HVNR), of the triggered noise and several felt earthquakes in Albania territory. From the results of this study, is concluded that fundamental frequency (F_0) and the amplification in this frequency (A_0), are almost the same for the microtremors and seismic events. As far as for the amplification factor, we concluded that on the sites of seismological stations situated on hard rock (basement) there is not amplification. In the contrary, for the Vlora station site, the amplification factor is 5-6 at fundamental frequency 6 Hz, showing that this station is not situated on the hard rock. The microtremors are a useful technique for the site assessment effects, used in microzonation of urban areas, that complement the lack of seismic data in a region (boreholes, geology, etc.)