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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Effects Of Signal Processing And Antenna Frequency On The Geostatistical Structure Of Ground-Penetrating Radar Data, Greg A. Oldenborger, Michael D. Knoll, Warren Barrash
Effects Of Signal Processing And Antenna Frequency On The Geostatistical Structure Of Ground-Penetrating Radar Data, Greg A. Oldenborger, Michael D. Knoll, Warren Barrash
CGISS Publications and Presentations
Recent research has suggested that the geostatistical structure of ground-penetrating radar data may be representative of the spatial structure of hydraulic properties. However, radar images of the subsurface can change drastically with application of signal processing or by changing the signal frequency. We perform geostatistical analyses of surface radar reflection profiles in order to investigate the effects of data processing and antenna frequency on the semivariogram structure of radar reflection amplitudes. Surface radar reflection data collected at the Boise Hydrogeophysical Research Site illustrate the processing- and antenna-dependence of radar semivariograms for a fluvial, cobble-and-sand aquifer. Compensating for signal attenuation and …
Seismic Expression Of Pleistocene Paleoceanographic Changes In The California Borderland From Digitally Acquired 3.5 Khz Subbottom Profiles And Ocean Drilling Program Leg 167 Drilling, Aleksandra Janik, Mitchell W. Lyle, Lee M. Liberty
Seismic Expression Of Pleistocene Paleoceanographic Changes In The California Borderland From Digitally Acquired 3.5 Khz Subbottom Profiles And Ocean Drilling Program Leg 167 Drilling, Aleksandra Janik, Mitchell W. Lyle, Lee M. Liberty
CGISS Publications and Presentations
We correlate processed 3.5 kHz seismic profiles with physical properties of cores collected during ODP Leg 167 from the Tanner, East Cortes, and San Nicolas Basins through much of the Pleistocene succession. Results indicate that seismic horizons in the unconsolidated Pleistocene sediments (top 50 m) are mainly controlled by density contrasts. Removing of the compaction trend from the density reveals a very interesting relationship between density and composition - the density closely and inversely correlates with organic carbon indicating that large-scale variations in organic carbon are responsible for seismic reflections through their influence on density. This is a significant discovery …
Multivariate Analysis Of Cross-Hole Georadar Velocity And Attenuation Tomograms For Aquifer Zonation, Jens Tronicke, Klaus Holliger, Warren Barrash, Michael D. Knoll
Multivariate Analysis Of Cross-Hole Georadar Velocity And Attenuation Tomograms For Aquifer Zonation, Jens Tronicke, Klaus Holliger, Warren Barrash, Michael D. Knoll
CGISS Publications and Presentations
We have investigated the potential of combining cross-hole georadar velocity and attenuation tomography as a method for characterizing heterogeneous alluvial aquifers. A multivariate statistical technique, known as k-means cluster analysis, is used to correlate and integrate information contained in velocity and attenuation tomograms. Cluster analysis allows us to identify objectively the major common trends in the tomographic data and thus to ‘‘reduce’’ the information to a limited number of characteristic parameter combinations. The application of this procedure to two synthetic data sets indicates that it is a powerful tool for converting the complex relationships between the tomographically derived velocity …
Design Of Geophysical Surveys In Transportation, Paul Michaels
Design Of Geophysical Surveys In Transportation, Paul Michaels
CGISS Publications and Presentations
Designing geophysical investigations for transportation related projects requires special attention to the constraints imposed by right-of-way, irregular topography, noise from traffic, and the need to avoid the interruption of traffic flow. A geophysical engineer needs to be prepared to consider these design issues that are not addressed in a standard procedure such as ASTM D-5777. The author presents design strategies that address these issues, and illustrates the concepts with case histories taken from bridge and highway projects. Beam steering, broadside shooting, and non-traditional designs that preserve alternative analysis options are presented. Transportation engineers who augment traditional subsurface geotechnical surveys with …