HR: 14:25h
AN: NS13A-04 INVITED    [Abstracts]
TI: The Contribution of Robert F. Corwin to Self-Potential and Geotechnical Geophysics
AU: * Fitterman, D V
EM: fitter@usgs.gov
AF: U.S. Geological Survey, Box 25046 MS 964, Denver, CO 80225, United States
AB: Throughout his career, Robert F. Corwin developed innovative geophysical methods to solve geotechnical problems. Most notable is his work on self-potential (SP) where his focus was a blend of electricity and water, a potentially lethal brew, to solve very practical problems. Corwin's work in SP started with the idea of applying the technique to marine mineral exploration; this early work is characterized by a theme that ran through his career: understanding the effects that can influence measurements, developing methodologies to obtain consistent and reliable data, and interpreting those data in a conservative and believable manner supported by the facts. He expanded the electricity-water connection to geothermal fluids and the SP signals produced by them. He was involved in geothermal exploration throughout the western U.S. including Alaska and Mexico. In addition to developing reliable field techniques he worked on interpretational methods that made SP interpretation quantitative. Corwin's most significant contribution was the study of leaky dams using SP. Water leakage produces an SP anomaly because of the electrokinetic properties of geologic materials. Through a series of SP studies for the U.S. Bureau of Reclamation and the U.S. Army Corps of Engineers he developed a methodology for making and interpreting SP measurements that helped locate, assess, and remediate leakage. This success led to numerous surveys throughout Canada for regional power authorities. Corwin returned to marine geophysical studies throughout his career including SP measurements to locate moveable concrete mats placed in the Mississippi River to control bank erosion. Because of changes in river flow, these large articulated mats were often undercut, moved, and reburied causing hazardous bank conditions. SP and electrical resistivity measurements were found to accurately locate the mats. Corwin also worked on electrical resistivity measurements of the ocean floor. Starting with stationary seafloor measurements to characterize bottom cover he eventually developed a moving measurement system, which private companies routinely use to survey routes and potential hazards on the ocean floor before they lay deep ocean cables.
DE: 0900 EXPLORATION GEOPHYSICS
DE: 0925 Magnetic and electrical methods (5109)
DE: 1808 Dams
DE: 1835 Hydrogeophysics
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting