Estimation of crustal Qβ in the NW Himalaya using teleseismic broadband SH waveforms of the 8 October 2005 South Asian earthquake

Abstract

The average value of the intrinsic shear wave quality factor, Qβ, for the 15 km of the upper crust in the NW Himalaya is estimated. Thirty-two teleseismic broadband SH and sSH waveforms of 8 October 2005 South Asian earthquake (Mw = 7.6), from sixteen Global Seismographic Network stations of the National Earthquake Information Center network have been used. The selected windows of the direct and depth phases have been Fourier transformed and smoothed using the Hamming and Tuckey technique. Ratio of the smoothed spectra of depth and direct phases are obtained in the frequency range 0.2–1.5 Hz. A straight line is fitted in the least-square sense to the spectral ratio versus frequency. The value of Qβ is estimated from the slope of the line. The frequency independent average value of Qβ is estimated to be 218±56.