Seismotectonics of the Hindukush and Baluchistan arc

摘要: Abstract A seismicity map of that part the Pakistan-Afghanistan region lying between latitudes 28° to 38°N and longitudes 66° 75°E is given using all available data for period 1890–1970. The earthquakes magnitude 4.5 above were considered in preparation this map. On basis map, it observed pattern over well-known Hindukush quite complex. Two prominent, mutually orthogonal, lineaments, namely northvestern north-eastern trends, characterize area. northwestern trend appears extend from Main Boundary Fault Kashmir Himalaya on southeast plains Amu Darya Uzbekistan northwest beyond Hindukush. Sulaiman Kirthar ranges Pakistan are well-defined zones intermontane exhibiting north-south alignment. Thirty-two new focal-mechanism solutions above-mentioned have been determined. These, together with results obtained by earlier workers, suggest pre-dominance strike-slip faulting Hazara Mountains, wrench zone zone, as well supposed extension Murray ridge up Karachi coast, appear be mostly undergoing movements. In region, thrust found equally prevalent. Almost thrust-type mechanisms belonging area both nodal planes NW-SE direction shallow intermediate depth earthquakes. dip P-axes events indicating type rarely exceeds 35°. seismic slip vector through always directed towards northeast. epicentral these a deep-seated fault paralleling northwesterly underneath This NW-lineament has preference faulting, vicinity orthogonal NW-seismic there NE-seismic lineament which faulting. discussed point view convergence Indian Eurasian plates light plate tectonics theory.