Imaging of the Hypersaline Mono Lake with Marine Resistivity: A Feasibility Study
D. Rucker and N. Crook
Event name: SAGEEP 2017 - 30th Annual Symposium on the Application of Geophysics to Engineering and Environmental Problems
Session: DC & IP Electrical Methods I
Publication date: 19 March 2017
Info: Extended abstract, PDF ( 1.02Mb )
A short, waterborne streamer resistivity survey was conducted at Mono Lake in California. The lake, located on the eastern side of the Sierra Nevada Mountains, contains a significant amount of dissolved solids, resulting in hypersaline conditions, due to being a terminal lake with no outlet. The survey was conducted to determine if the method could be used to define subbottom sediments and geological structure to answer questions related to recent-past volcanic and tectonic events. The survey used a streamer resistivity cable with a 15-meter electrode spacing, towed at approximately 2 mph behind a small survey vessel. The survey was limited in scope to collecting approximately 6000 meters of data within the western cove, where significant core sampling has been conducted. The survey revealed that data of good quality could be obtained despite the lake’s conductivity being in excess of 84,000 uS/cm. Below the lake bottom, the resistivity models reconstructed geological material upwards of 400 ohm-m to depths of 35 meters, which likely represent hard rock. We conclude that the method could be used to map most of the shallow areas of the lake, where the water column is less than 20 meters. The deepest areas of the lake, south of Paoha Island, would require streamer resistivity cables with an electrode spacing of at least 60 meters.