부산대학교 도서관

Pakistan is situated very close to the subduction zone of Indian-Arabian plates and Indian-Eurasian plates. Thus, it is a country with moderate to high seismicity with a large number of major earthquakes. Therefore, the severity of seismic hazards of major earthquakes is not ignorable. The seismicity of northern areas of Pakistan (33-37°N and 70-76°E), which are the part of North West Himalaya, is studied. Three earthquake catalogues are selected and then completed for this purpose. The spatial distribution of their epicenters, as a function of depth, shows that most of the earthquakes (about 84 %) occurred in shallow to intermediate depths. Relationship between major faults and their source mechanism is also investigated. The Focal mechanism solutions of 39 significant earthquakes in this area, occurred in the period of 1976-2014 with magnitude M > 5.0, are also analyzed. The focal depth of these events is in the range of 10-244 km. Among 39 focal mechanisms, the majority of them located in lower crust. Global centroid moment tensor solutions indicate that the majority of the seismic events show strike-slip faulting with a left-lateral sense of motion, followed by thrust and normal faulting. Most of these focal mechanisms located in the Hindu-Kush, a most seismically active, region. The major source of these events and thrusting is the subduction of the Indian plate under the Eurasian Plate. At shallow to intermediate depth, low-to-intermediate angle thrust faulting is dominant. It is seen that in a large number of seismic events the compressive stress is acting nearly in NNW-SSE to N-S directions. [ABSTRACT FROM AUTHOR]