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Full-Text Articles in Physical Sciences and Mathematics
Instantaneous Spectral Analysis: Time-Frequency Mapping Via Wavelet Matching With Application To Contaminated-Site Characterization By 3d Gpr, John H. Bradford, Yafei Wu
Instantaneous Spectral Analysis: Time-Frequency Mapping Via Wavelet Matching With Application To Contaminated-Site Characterization By 3d Gpr, John H. Bradford, Yafei Wu
CGISS Publications and Presentations
Spectral decomposition, by which a time series is transformed from the 1D time/amplitude domain to the 2D time/spectrum domain, has become a popular and useful tool in seismic exploration for hydrocarbons. The windowed, or short-time Fourier transform (STFT) was one early approach to computing the time-frequency (t-f) distribution. This method relies on the user selecting a fixed time window, then computing the Fourier spectrum within the time window while sliding the window along the length of the trace. The primary limitation of the STFT is the fixed window which prevents either time localization of high frequency components (if …
Applying Reflection Tomography In The Postmigration Domain To Multifold Ground-Penetrating Radar Data, John H. Bradford
Applying Reflection Tomography In The Postmigration Domain To Multifold Ground-Penetrating Radar Data, John H. Bradford
CGISS Publications and Presentations
Acquisition and processing of multifold ground-penetrating radar (GPR) data enable detailed measurements of lateral velocity variability. The velocities constrain interpretation of subsurface materials and lead to significant improvement in image accuracy when coupled with prestack depth migration (PSDM). Reflection tomography in the postmigration domain was introduced in the early 1990s for velocity estimation in seismic reflection. This robust, accurate method is directly applicable in multifold GPR imaging. At a contaminated waste facility within the U.S. Department of Energy’s Hanford site in Washington, the method is used to identify significant lateral and vertical velocity heterogeneity associated with infilled waste pits. Using …