HR: 0830h
AN: T21C-0473    [PDF]
TI: Neotectonic uplift of the central Dead Sea fault (Lebanon and Syria) revealed by InSAR and DEM analysis
AU: * Gomez, F
EM: fgomez@missourui.edu
AF: Department of Geological Sciences, 101 Geological Sciences Bldg. University of Missouri, Columbia, MO 65211 United States
AU: Khawlie, M
AF: LNCRS, Lebanese National Center for Remote Sensing, Beirut, 00000 Lebanon
AU: Tabet, C
AF: CNRS, Lebanese National Council for Scientific Research, Beirut, 00000 Lebanon
AU: Khair, K
AF: Department of Geology, American University of Beirut, Beirut, 00000 Lebanon
AU: Darkal, A
AF: Department of Geology, Damascus University, Damascus, 00000 Syrian Arab Republic
AU: Barazangi, M
AF: Institute for the Study of the Continents, Snee Hall Cornell University, Ithaca, NY 14853 United States
AB: A 200 km long restraining bend along central Dead Sea fault (DSF), the transform boundary between the Arabian and African plates, has resulted in the uplift of the Mount Lebanon and Anti Lebanon ranges. The length scale of this restraining bend compares with other large bends observed along continental transforms, including the Big Bend along the Sand Andreas fault system. Our study of active and late Cenozoic tectonism along the central DSF includes the application of Synthetic Aperture Radar Interferometry (InSAR) for the construction of a high resolution (20 meter pixel) digital elevation model (DEM) and to assess present-day vertical motions. The DEM provides a base to assess neotectonic uplift through mapping of macro-scale geomorphic features and morphometric analyses. The regional pattern of late Cenozoic uplift is revealed by a late Neogene paleo-surface that demonstrates greater uplift and erosion in the Mount Lebanon range compared with the Anti Lebanon range. The present-day geometry of this paleo-surface also suggests structural segmentation. Morphometric analyses, including relief and stream length-gradient indices, further illuminate the spatial distribution of uplift and/or tilting. Preliminary results of InSAR point target analysis yield insight into present-day vertical movements. Uplift and subsidence measured by InSAR may represent elastic loading of dip-slip faults beneath the Lebanese ranges. Asymmetric uplift patterns correspond with differences in the overall structures of the Mount Lebanon (a monocline) and the Anti Lebanon (broad anticlinorium). These structural differences may reflect competing influences of adjacent tectonic features including the Lebanese passive margin and the intracontinental Palmyride fold belt (in southern Syria). The obliquity of the Arabian-African plate motions relative to the restraining bend suggests that NW-SE crustal shortening locally accommodates a significant amount of the total 5 - 10 mm/yr. plate motion. It is plausible that some of the historically documented earthquakes during the past 2,000+ years may have occurred along dip-slip faults, instead of strike-slip faults. Hence, dip-slip faulting and related folding present an important, but little studied, element of the regional earthquake hazard.
DE: 1824 Geomorphology (1625)
DE: 7230 Seismicity and seismotectonics
DE: 8107 Continental neotectonics
DE: 8109 Continental tectonics--extensional (0905)
SC: Tectonophysics [T]
MN: 2003 Fall Meeting