Determination of seismic site classification of seismic recording stations in the Himalayan region using HVSR method

An attempt has been made to classify seismic stations installed along the Himalayan belt and in adjoining regions using recorded strong-motion data and different empirical methods. For all recorded data, HVSRs (horizontal-to-vertical spectral ratios) were computed using pseudo-response spectral acceleration (PSA) values. Five empirical techniques based on HVSRs and PSA were used to classify the stations. The first and second methods are based on the predominant period of the site and relationship between lino and parameters of HVSR. The third and fourth methods compute the correlation between the HVSR curve of a station and standard HVSR curves. Fifth used the PSA and PGA (peak ground acceleration) to identify the site as rock and soil. Conclusively, the site class which had the highest frequency of occurrence amongst the five methods was determined to be the final class for a given station. The final site class recommended is matched with the existing available site classification and also with available field test results.