Banerjee Soham, Kumar Abhishek (2017), Determination of Seismic Wave Attenuation for the Garhwal Himalayas, India, Geosciences Research, DOI: 10.22606/gr.2017.22005

(a) The Locations of the earthquake epicenters and recording stations are shown in blue earthquake symbols and orange home symbols respectively; (b) Q-f correlation for P and S wave in Garhwal region
(a) The Locations of the earthquake epicenters and recording stations are shown in blue earthquake symbols and orange home symbols respectively; (b) Q-f correlation for P and S wave in Garhwal region

Present work determines the seismic wave attenuation characteristics in the Garhwal Himalayan, India. These are obtained based on the attenuations of P, S and coda wave spectra from the recorded seismograms of nearby earthquakes (EQs) with focal depth up to 10 km. Since P and S waves come directly to the site, attenuation of P and S waves in the present study represent the crustal attenuation characteristics of the region whereas coda wave appears from deeper lithospheric regions thus coda wave attenuation represent the attenuation characteristics of deeper lithospheric regions. Above attenuation characteristics are frequency dependent and are shown in terms of the Quality factors . The average  correlation  for P, S and coda waves obtained in the present study are  ,  and  respectively. Value of  ratio greater than 1 for the study area suggests that the crust beneath this region is composed of dry rocks. In addition,  correlation for coda wave are also determined with the increasing lapse time suggesting that the upper lithosphere of Garhwal Himalayas is more heterogeneous than the lower lithosphere. The obtained  correlations are essential for creating a Ground motion model in this region.

Full Text