Seismic site classification based on H/V spectral ratio from strong ground motion records: the urban areas of Bursa province

Abstract

It is known that the site classifications are closely related to the damages caused by earthquakes in areas with increased seismic hazard. Additionally, another important parameter utilized to identify the damage is the Peak Ground Acceleration (PGA) value. While measurements and the GMPE are utilized to identify PGA values, site classification is usually conducted by using the Vs30 value. This study aims to identify the site classifications for Bursa province by using a different approach, namely, the H/V spectral ratio method based on the dominant periods. In this regard, 205 records belonging to 82 earthquakes recorded by 41 strong ground motion stations located in Bursa province were utilized. A mean H/V spectral ratio curve was developed for each station based on the Fourier and response spectra of these earthquake records. Generally, double or multiple peaks resulting from the site structure were observed in the H/V curves. Furthermore, for the station locations, the evaluations were conducted in accordance with the site classifications per the dominant period as it is suggested in the literature. The stations were identified as all of the site classifications suggested by (Zhao et al. Bull Seismol Soc Am 96:914–925, 2006), as SC-1, 2, 3 and 5 suggested by (Fukushima et al. J Earthquake Eng 11:712–724, 2007) and as CL I, II, III, IV and VII suggested by (Di Alessandro et al. Bull Seismol Soc Am 102:680–695, 2012). Additionally, various Spectral Acceleration estimations were made with different GMPE equations for scenario earthquakes, and the results were compared with the design spectra suggested by the Turkish Building Earthquake Code (TBEC 2018). As a result of the study, the H/V spectral curves were generated according to both Fourier and response spectra; using a great number of earthquake data, the hazard was assessed by the soil dominant period-based for the first time in Bursa province.