George A. McMechan

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Ž . Time domain 2.5-D finite-difference simulations of ground-penetrating radar GPR responses from models of buried human remains suggest the potential of GPR for detailed non-destructive forensic site investigation. Extraction of information beyond simple detection of cadavers in forensic investigations should be possible with current GPR technology. GPR(More)
Ideally, characterization of hydrocarbon reservoirs requires information about heterogeneity at a submeter scale in three dimensions. Detailed geologic information and permeability data from surface and cliff face outcrops and boreholes in the alluvial part of the Ferron Sandstone are integrated here with three-dimensional (3-D) ground-penetrating radar(More)
To decouple the parameters in elastic full-waveform inversion (FWI), we evaluated a new multistep-length gradient approach to assign individual weights separately for each parameter gradient and search for an optimal step length along the composite gradient direction. To perform wavefield extrapolations for the inversion, we used parallelized high-precision(More)
Ground-penetrating radar (GPR) surveys, outcrop measurements, and cores provide a high resolution threedimensional geologic model to investigate the effects of shales in marine-influenced lower delta-plain distributary channel deposits within the Cretaceous-age Ferron sandstone at Corbula Gulch in central Utah, USA. Shale statistics are computed from(More)
A parallel 3-D two-point ray tracing is implemented and successfully applied to to-mography and prestack Kirchhoo migration using an 8 node iPSC/860 Intel computer. The salient features of the travel time calculation, tomography, and migration algorithms , their decomposition strategies, I/O, and performances on a parallel environment are demonstrated using(More)
As oil and gas exploration moves into deeper offshore areas, Shallow Water Flow (SWF) from overpressured, unconsolidated/uncemented sands becomes a high profile drilling hazard. Laboratory measurements show that SWF sands have high seismic compressional to shear velocity (Vp/Vs) ratios. Thus, elastic seismic inversion for Vp/Vs provides a quantitative(More)