Seismotectonics of the Western Himalayas : application to earthquake hazard and collisional tectonics : final report covering period August 30, 1990 to October 30, 1994

During the first year (8/90-8/91), the project studied instrumentally located earthquakes reported by the International Seismological Center. During the second year, the project studied earthquakes in the Pamirs and Karakorum. In the third year the project deployed and operated an 11-station temporary seismic array in the Pakistani Himalayas. The project trained Pakistani scientists to operate digital seismic recording systems, and left computer programs and a complete set of data. The research showed that moderate-sized subcrustal events that have occurred in the Nepal Himalayas could occur in the western Himalayas. A detailed three-dimensional analysis of the velocity structure beneath the western Himalayas reveals a buried foreland basin, which may trap gas and oil. Thus, the seismic results may eventually lead to new discoveries in oil and gas in the Pakistan Himalayas. The data from the temporary seismic deployment indicate there is no appreciable large-scale azimuthal anisotropy beneath this part of the Himalayas. Therefore, if there is any significant strain in the uppermantle beneath this area, it must be vertically oriented. (Author abstract)