USE OF STKONG-MOTION DATA FOR FREQUENCY-DEPENDENT SHEAR WAVE ATTENUATION STUDIES IN THE PITHORAGARH REGION OF KUMAON HIMALAYA

摘要

The Pithoragarh district in the state of Uttarakhand, India lies in the border region of India and Nepal and falls in the seismically active zone of Kumaon Himalaya. A local network of eight strong-motion accelerographs has been installed in this region since March 2006. The installed strong-motion instruments have recorded several events in this region. These events are located using HYP071 and the processed digital data is used for obtaining the frequency-dependent shear wave attenuation. This paper presents a method of finding Q_β(f) from the strong-motion data, which is based on the modified method of Joshi (2006). Based on the availability of data, hypocentral parameters, and clear S-phases, a total of 27 strong-motion records from six stations are used in this work. By using the inversion algorithm developed in this work, an average relation in the form, Q_β(f) = 30f~(1.45),is obtained for the Pithoragarh region of Kumaon Himalaya.