Walter A. Barnhardt, PhD (Former Employee)
Science and Products
Filter Total Items: 39
Influence of near-surface stratigraphy on coastal landslides at Sleeping Bear Dunes National Lakeshore, Lake Michigan, USA Influence of near-surface stratigraphy on coastal landslides at Sleeping Bear Dunes National Lakeshore, Lake Michigan, USA
Lake-level change and landslides are primary controls on the development of coastal environments along the coast of northeastern Lake Michigan. The late Quaternary geology of Sleeping Bear Dunes National Lakeshore was examined with high-resolution seismic reflection profiles, ground-penetrating radar (GPR), and boreholes. Based on sequence-stratigraphic principles, this study recognizes...
Authors
W. A. Barnhardt, B. E. Jaffe, R. E. Kayen, G.R. Cochrane
Sand volume and distribution on the paraglacial inner continental shelf of the northwestern Gulf of Maine Sand volume and distribution on the paraglacial inner continental shelf of the northwestern Gulf of Maine
In an extensive program of side-scan sonar and seismic reflection profiling, bottom sampling and vibracoring, we have mapped the western Gulf of Maine between Canada and Massachusetts, from the shoreline to the 100 m isobath. The purpose of the program was, in part, to locate and evaluate sand resources on the inner shelf. Surficial sand occurs on only 7% of this formerly glaciated...
Authors
J. T. Kelley, S.M. Dickson, D. F. Belknap, W. A. Barnhardt, D.C. Barber
The internal structure of sand bars on the Colorado River, Grand Canyon, as determined by ground-penetrating radar The internal structure of sand bars on the Colorado River, Grand Canyon, as determined by ground-penetrating radar
High-resolution, subsurface imagery from ground-penetrating radar (GPR) has revealed the internal structure of sand bars at seven sites on the Colorado River, Grand Canyon. Based on reconnaissance-level surveys, we recognized three stratigraphic units and several intervening unconformities. Unit A, which exhibits hyperbolic reflections and always occurs at the base of the section, is...
Authors
Walter A. Barnhardt, Robert Kayen, David Rubin, Diane L. Minasian
Radar structure of earthquake-induced, coastal landslides in Anchorage, Alaska Radar structure of earthquake-induced, coastal landslides in Anchorage, Alaska
Ground-penetrating radar (GPR) was used to investigate the internal structure of two large landslides in Anchorage, Alaska that resulted from the great 1964 earthquake. The Government Hill and Turnagain Heights landslides occurred in similar stratigraphic and geographic settings, yet the style of ground deformation is different at each site. GPR data are compared with previous...
Authors
Walter Barnhardt, Robert E. Kayen
Non-destructive measurement of soil liquefaction density change by crosshole radar tomography, Treasure Island, California Non-destructive measurement of soil liquefaction density change by crosshole radar tomography, Treasure Island, California
A ground penetrating radar (GPR) experiment at the Treasure Island Test Site [TILT] was performed to non-destructively image the soil column for changes in density prior to, and following, a liquefaction event. The intervening liquefaction was achieved by controlled blasting. A geotechnical borehole radar technique was used to acquire high-resolution 2-D radar velocity data. This method...
Authors
Robert E. Kayen, Walter A. Barnhardt, Scott Ashford, Kyle Rollins
Evaluation of landslide hazards with ground-penetrating radar, Lake Michigan coast Evaluation of landslide hazards with ground-penetrating radar, Lake Michigan coast
Ground-penetrating radar (GPR) and boreholes were used to investigate a landslide-prone bluff at Sleeping Bear Dunes National Lakeshore on the northeastern coast of Lake Michigan. Based on borehole observations, sediment underlying the area is homogeneous, consisting of well-sorted, medium to coarse sand. GPR penetrated up to 20 m deep in these sediments, revealing the late Quaternary...
Authors
Walter A. Barnhardt, Bruce E. Jaffe, Robert Kayen
Science and Products
Filter Total Items: 39
Influence of near-surface stratigraphy on coastal landslides at Sleeping Bear Dunes National Lakeshore, Lake Michigan, USA Influence of near-surface stratigraphy on coastal landslides at Sleeping Bear Dunes National Lakeshore, Lake Michigan, USA
Lake-level change and landslides are primary controls on the development of coastal environments along the coast of northeastern Lake Michigan. The late Quaternary geology of Sleeping Bear Dunes National Lakeshore was examined with high-resolution seismic reflection profiles, ground-penetrating radar (GPR), and boreholes. Based on sequence-stratigraphic principles, this study recognizes...
Authors
W. A. Barnhardt, B. E. Jaffe, R. E. Kayen, G.R. Cochrane
Sand volume and distribution on the paraglacial inner continental shelf of the northwestern Gulf of Maine Sand volume and distribution on the paraglacial inner continental shelf of the northwestern Gulf of Maine
In an extensive program of side-scan sonar and seismic reflection profiling, bottom sampling and vibracoring, we have mapped the western Gulf of Maine between Canada and Massachusetts, from the shoreline to the 100 m isobath. The purpose of the program was, in part, to locate and evaluate sand resources on the inner shelf. Surficial sand occurs on only 7% of this formerly glaciated...
Authors
J. T. Kelley, S.M. Dickson, D. F. Belknap, W. A. Barnhardt, D.C. Barber
The internal structure of sand bars on the Colorado River, Grand Canyon, as determined by ground-penetrating radar The internal structure of sand bars on the Colorado River, Grand Canyon, as determined by ground-penetrating radar
High-resolution, subsurface imagery from ground-penetrating radar (GPR) has revealed the internal structure of sand bars at seven sites on the Colorado River, Grand Canyon. Based on reconnaissance-level surveys, we recognized three stratigraphic units and several intervening unconformities. Unit A, which exhibits hyperbolic reflections and always occurs at the base of the section, is...
Authors
Walter A. Barnhardt, Robert Kayen, David Rubin, Diane L. Minasian
Radar structure of earthquake-induced, coastal landslides in Anchorage, Alaska Radar structure of earthquake-induced, coastal landslides in Anchorage, Alaska
Ground-penetrating radar (GPR) was used to investigate the internal structure of two large landslides in Anchorage, Alaska that resulted from the great 1964 earthquake. The Government Hill and Turnagain Heights landslides occurred in similar stratigraphic and geographic settings, yet the style of ground deformation is different at each site. GPR data are compared with previous...
Authors
Walter Barnhardt, Robert E. Kayen
Non-destructive measurement of soil liquefaction density change by crosshole radar tomography, Treasure Island, California Non-destructive measurement of soil liquefaction density change by crosshole radar tomography, Treasure Island, California
A ground penetrating radar (GPR) experiment at the Treasure Island Test Site [TILT] was performed to non-destructively image the soil column for changes in density prior to, and following, a liquefaction event. The intervening liquefaction was achieved by controlled blasting. A geotechnical borehole radar technique was used to acquire high-resolution 2-D radar velocity data. This method...
Authors
Robert E. Kayen, Walter A. Barnhardt, Scott Ashford, Kyle Rollins
Evaluation of landslide hazards with ground-penetrating radar, Lake Michigan coast Evaluation of landslide hazards with ground-penetrating radar, Lake Michigan coast
Ground-penetrating radar (GPR) and boreholes were used to investigate a landslide-prone bluff at Sleeping Bear Dunes National Lakeshore on the northeastern coast of Lake Michigan. Based on borehole observations, sediment underlying the area is homogeneous, consisting of well-sorted, medium to coarse sand. GPR penetrated up to 20 m deep in these sediments, revealing the late Quaternary...
Authors
Walter A. Barnhardt, Bruce E. Jaffe, Robert Kayen