The seismic microzonation map of Yenisehir-Bursa, NW of Turkey by means of ambient noise measurements

Unal DİKMEN and Mete MİRZAOĞLU

General Directorate of Disaster Affairs, Earthquake Research Department, Ankara, Turkey

Abstract: This paper describes the results of the study of seismic microzonation at Yenisehir-Bursa which is located at the Northwestern part of Turkey. Seismic noise measurements have been made at 151 sites. Short periods (less than 1 second) were taken into account at the main peak in the spectral ratio between the horizontal and the vertical components. At the investigated area, two maps were prepared that show the spatial variations of the predominant period and seismic amplification according to Nakamura’s technique. The analysis shows that the north and south edges of the Yenisehir basin have relatively high predominant periods and high seismic amplification compared to the centre of the basin. This result is in line with the theory of topographic effects on seismic amplification and also confirmed the suitability of the H/V spectral ratio of ambient noise as a geophysical exploration tool in seismic hazard assessment.