Abstract
Motivated by the need to image faults to test Cenozoic extension models
for the Death Valley region of the western basin and range province,
an area of strong lateral velocity variations, we examine the geometry
of normal faulting in southern Death Valley by seismic depth imaging.
We analyze COCORP Death Valley Line 9 to attain an enhanced image
of shallow fault structure to 2.5 km depth. Previous work used standard
seismic processing to infer normal faults from bed truncations, displacement
of horizontal reflectors, and diffractions. We obtain a detailed
velocity model by nonlinear optimization of first- arrival times
picked from shot gathers, examine the unprocessed data for fault
reflections, and use a Kirchhoff prestack depth imaging procedure
to handle lateral velocity variations and arbitrary dips properly.
Fault-plane reflections reveal the listric true-depth geometry of
the normal fault at the Black Mountains range front in southern Death
Valley. This is consistent with the concept of low-angle extension
in this region and strengthens its association with crustal-scale
magmatic plumbing
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