HR: 0830h
AN: T51F-0217    [PDF]
TI: An Integrated Geophysical study of the Lithospheric Structure Beneath Libya
AU: * Brown, W A
EM: wesley@geo.utep.edu
AF: University of Texas at El Paso, Dept of Geologicas Sciences, El Paso, TX 79968 United States
AU: Doser, D I
EM: doser@geo.utep.edu
AF: University of Texas at El Paso, Dept of Geologicas Sciences, El Paso, TX 79968 United States
AU: Keller, R G
EM: keller@geo.utep.edu
AF: University of Texas at El Paso, Dept of Geologicas Sciences, El Paso, TX 79968 United States
AB: The tectonic evolution of Libya has yielded a complex crustal structure, which is composed of a series of basins and uplifts. A considerable amount of oil exploration has been undertaken in the area and numerous studies have been published on the shallow ($<10$km depth) geology and geophysics of the region. In addition, over 6000 gravity measurements are available for the northern Libya region. We are using these data in conjunction with other geologic and geophysical control to construct a 3-D model of density/geology for northern Libya and surrounding regions. Knowing the surface geology and having a digital elevation model and observed gravity value at specified stations, we first calculate the gravity contribution for polygonal areas assuming infinite depth. We then calculate the gravitational contribution for the same polygonal area using the Paleozoic surface as the elevation, assuming uniform density for the volume of rocks below the Paleozoic surface. Subtracting the value calculated at the Paleozoic layer from the gravitational value at the surface yields a gravitational value matching that of the layer between the surface and the top of the Paleozoic layer. The same procedure is then repeated for the top of the Precambrian, the Moho, etc. The 3-D model will then be used to develop a regional velocity model that can be verified/modified by analysis of regional seismic waveform data we are collecting from earthquakes occurring within northern Libya. Northern Libya is the most seismologically active and highly faulted portion of the country. For this reason we have collected thirteen Landsat 5 satellite images covering the most seismically active and structurally significant regions of northeast and northwest Libya. The satellite images have been mosaicked using a seamless mosaicking technology based on ENVI's cutline feathering approached. The resulting mosaicked figures were then overlain with the previously mapped faults analyzed to identify the more recent faults.
DE: 0905 Continental structures (8109, 8110)
DE: 8122 Dynamics, gravity and tectonics
SC: Tectonophysics [T]
MN: 2003 Fall Meeting