Time domain electromagnetic surveys for assisting in determining the groundwater resources on the Island of Lanai, Hawaii : preliminary report

Abstract

"This report contains the results of surface Time Domain Electromagnetic (TDEM) geophysical surveys performed on the Island of Lanai for Lanai Water Company. The surveys were conducted by Blackhawk GeoSciences from August 13 to August 19, 2001. Blackhawk has conducted several previous TDEM surveys on Lanai. The results of these surveys are summarized in Blackhawk project report number 9081-000, dated December 15, 1994. TDEM is a geophysical method that determines from the surface the geoelectric section (resistivity layering) of the subsurface. From the geoelectric section, information about geology and water quality can be inferred. The electrical resistivity of the earth depends on lithology, porosity, and concentration of dissolved solids in the ground water. The general objectives of the measurements on Lanai were to further refine the interpreted location of groundwater damming structures, and explore for possible anomalous basal groundwater occurrences (i.e. springs, relative thick basal layers). TDEM surveys were conducted in seven areas on the Island."