Application of teleseismic receiver functions and gravity for Moho depth mapping: a case study of the Western Himalayas

Abstract

This study presents the coherently stacked P-wave receiver functions and bouguer anomaly mapping of Western Himalayas (longitude 71°-74°E and latitude 31°-34°N ) to estimate crustal thickness. Data used for Pwave receiver function is from local seismic network of Pakistan whereas, gravity data is extracted from Topex available in public domain for research. The crust thickness and average crust Vp/Vs ratio at each station of the network is obtained by coherently stacking the Ps, PpPs, PpSs + PsPs phases of 15 seismic stations. The data used in this study was collected from 2012 to 2019, events with magnitudes mb ≥ 6 and epicenteral distances 30°to 95°were chosen. There is a significant difference in Moho depth beneath the broadband seismic stations used for the investigations. Moho depth mapping: A case study of Western HimalayasMoho depth is 36 km in the south, on average 46 km in the center, and 52 km at the northernmost seismic station of the study area. In general, the crust is dipping from South to North for the study area. In order to support this interpreted argument of moho-depth variation from P-Wave receiver function, residual calculation of bouguer anomaly data was carried out as well. The residuals showing a variation of anomalous data from -89 to 193 mGal in study area have presented a promising correlation and favored the argument of crustal dipping as suggested by P-wave function from seismic network. The trend confirms that the crustal thickening and shortening is caused by the collision of Indian and Asian plates.