Focal mechanism study of the Chakwal Earthquake of July 16, 2001 in the light of regional tectonics
Abstract
On July 16, a body wave magnitude 5.2 (Ms 4.7) earthquake occurred near Chakwal, about 75 kin south of Islamabad. The earthquake was widely felt from Peshawar to Lahore. The fault-plane solution on the basis of P-wave polarity data of seismic stations of the PAEC's (Pakistan Atomic Energy Commission) Seismic Network has been found well-controlled and comparable with the Centroid Moment Tensor Solution given by Harvard University. The fault plane is oriented in the WNW direction with strike, dip and slip of 303o, 66o and 148o respectively Which is in accordance with the local tectonics of the region. On the basis of Focal Mechanism Solution of this earthquake, along with two more solutions of earthquakes of the region, a possibility of another subsurface fault parallel to the Kallar Kahar fault is also derived.
References
Hussain, F., 1993. Geological Map of Pakistan. Pub. Geological Survey of Pakistan, Quetta, Pakistan.
Kazmi, A. He, & Jan, M. Q., 1997. Geology and Tectonics of Pakistan Graphic Publisher; Karachi p, 124.
Kami, A. H., 1979. Active Faults system in Pakistan. Geodynamics of Pakistan. Editors: Farah and Dejong; Geological Survey of Pakistan Quetta Pakistan.
Lee, W. H., & Lahr, J. C., 1975. HYP071. A Computer Code for Determining Hypocentral Parameters, Magnitude and First Motion Pattern of Local Earthquakes. USGS Open File Report No. 75-311.
Mubarak, M.A., Armbruster, J., Khan, S. A., Ali, I., Ahmad, S., and Ali, J., 1977. Rawalpindi Earthquake of 14th February 1977 and Associated shocks, Micro Seismic Studies Project, PINSTECH Internal Report No, MSSP-2/77.
Suetsagu, D., 1997. Source Mechanism Practice. Lecture notes, International Institute of Seismology and Earthquake Engineering, Tsukuba Japan 1997.
Wadia, D. N., 1978. Geology of India. 4th edition. McGraw Hill Publisher; New Dehli India.
