HR: 13:40h
AN: T33F-01    [Abstracts]
TI: Tectonic Setting of the 8 October 2005 Kashmir Earthquake
AU: * Yeats, R S
EM: yeatsr@geo.oregonstate.edu
AF: Geosciences, Oregon State University, 104 Wilkinson, Corvallis, OR 97331-5506, United States
AU: Hussain, A
EM: ahussain@brain.net.pk
AF: Earth Consultants International and Geological Survey of Pakistan, 57 Hussain-abad,Street 2, Peshawar, NWF N/A, Pakistan
AU: Meigs, A
AF: Geosciences, Oregon State University, 104 Wilkinson, Corvallis, OR 97331-5506, United States
AU: Yule, D
EM: Doug.Yule@csun.edu
AF: Geological Scieences, California State University Northridge, Northridge, CA 91330, United States
AU: Madden, C
EM: madden@earthconsultants.com
AF: Geosciences, Oregon State University, 104 Wilkinson, Corvallis, OR 97331-5506, United States
AU: Lisa, M
EM: lisa_qau@yahoo.com
AF: Earth Sciences, Quaid-i-Azam University, Islamabad, N/A N/A, Pakistan
AB: The source of the 8 October 2005 earthquake of M 7.6 was the northwest-striking Balakot-Bagh (B-B) fault, which had been mapped by the Geological Survey of Pakistan prior to the earthquake, but, except for a 16-km section near Muzaffarabad, had not been recognized as active. The fault follows the Indus-Kohistan Seismic Zone (IKSZ) and cuts across and locally offsets the Hazara-Kashmir syntaxis defined by the Main Boundary and Panjal thrusts. The fault has no expression in facies of the Miocene-Pleistocene Siwalik Group, but does offset late Pleistocene terrace deposits in Pakistan-administered Jammu-Kashmir. Two en-échelon anticlines near Muzaffarabad and Balakot expose Precambrian Muzaffarabad Limestone and are cut by the B-B fault on their southwest side, suggesting that folding and exposure of Precambrian rocks by erosion accompanied Quaternary displacement along the fault. The B-B fault has reverse separation, northeast side up; uplift of the northeast side accompanies displacement, producing high topography and steeper stream gradients northeast of the fault. Limited surface expression of the B-B fault has been found northwest of the syntaxis, although the IKSZ and steeper stream gradients continue at least as far as the Indus River, the site of the Pattan earthquake of M 6.2 in 1974. To the southeast, northwest-striking faults, one of which is flanked by an anticline exposing Precambrian limestone, were mapped by the Geological Survey of Pakistan. Farther southeast, in Indian-administered territory, active faulting may follow the Riasi thrust, where Holocene activity has been described. In the Kangra re-entrant still farther southeast, active faulting may follow the Soan thrust, along which Holocene and Pleistocene offsets have been described. The Soan thrust, rather than the south flank of the Janauri anticline, may represent the surface projection of the 1905 Kangra earthquake of M 7.8.
DE: 7205 Continental crust (1219)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 8002 Continental neotectonics (8107)
DE: 8108 Continental tectonics: compressional
DE: 8175 Tectonics and landscape evolution
SC: Tectonophysics [T]
MN: 2007 Fall Meeting