Abstract
North-west Himalayas and its adjoining regions have been experiencing deadly earthqaukes from time to time and are home for a large portion of population of Indian subcontinent. Knowledge of regional path attenuation and site parameters are prerequisite while attempting seismic hazard studies towards minimizing damages during future earthqaukes for a region. Present work focuses on the determination of path attenuation and site characteristics of earthqaukes recording stations, located in the north-west Himalayas and its adjoining regions, within India. It is done using two- step generalized inversion technique. In the first step of inversion, non-parametric attenuation curves are developed by constraining attenuation to be a smooth decaying function with hypocentral distance. Qs = (105 ± 11)f (0.94 ± 0.08) as S wave quality factor is obtained indicating that the region is seismically active having high degree of heterogeneities in the crustal medium. In the second step of generalized inversion, site amplification curve, at each recording station, is computed as the ratio of site spectral amplitude of horizontal and vertical components. In addition, based on Horizontal to vertical spectral ratio (HVSR) method, predominant frequency of each recording station is calculated. Values of predominant frequencies based on HVSR and generalized inversion are found matching for each of the recording station. Based on obtained predominant frequency, site class of 101 recording stations, which at present are absent, are determined in this work. Determined path attenuation as well as site parameters can be collectively used for developing regional ground motion models and subsequently for seismic hazard studies for the selected region.
Highlights
The Himalayan arc, extending approximately 2500km between Kashmir and Arunachal Pradesh within India, is one amongst the most seismically active regions across the globe
The values of n (= 0.94) and Q0 (= 105), obtained in this study indicate that the present study region is tectonically active, characterized by higher degree of heterogeneities
In the light of on-going seismicity and catastrophic damages witnessed during earlier EQs, of path attenuation as well as site characterization of PESMOS handled EQ recording stations, located in the north-west Himalayas and adjoining area of is attempted
Summary
The Himalayan arc, extending approximately 2500km between Kashmir and Arunachal Pradesh within India, is one amongst the most seismically active regions across the globe. EQ records from PESMOS recording stations located in the north-west Himalayas and its foothills within India (including the states of Himachal Pradesh, Uttarakhand, Punjab, Haryana and New Delhi), are analysed for estimating path attenuation and site characteristics separately. It is done based on two-step generalized inversion (GINV) of the S-wave Fourier spectra (hereafter referred to as GINV). Harinarayan and Kumar [2018] computed site parameters for recording stations in the north-west Himalayas in terms of predominant frequency (fpeak) alone using Horizontal to vertical spectral ratio (HVSR) based on the response spectra of the entire accelerogram
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
