Investigations of ground water flow associated with the Saratoga warm springs and the Tecopa Hot Springs near Death Valley, California, using magnetic and conductivity methods

Electrical and ground magnetic surveys at Saratoga Springs and Tecopa Hot Springs in the vicinity of Death Valley reveal intersecting faults that appear to control the spring locations. Faults striking east–west and north–south intersect at Saratoga Springs. High electrical conductivity along imaged faults at Saratoga Springs implies shallow ground water channels between 5 and 20 m deep. Regions of high conductivity correlate with water saturated zones or clays. Gradients in magnetic and conductivity data at Saratoga are interpreted as faults. Similarly northwest- and northeast-trending faults are inferred to intersect at Isolated Spring in Tecopa Valley. Our data suggest that ground water flow along deep structures allows water to be heated and could account for the water temperature of about 41 °C at the Springs at Bath in Tecopa Valley. However, we hypothesize that cold water from the Amargosa River percolates downward and mixes with hot water rising at the fault intersections. The river water accounts for the lower water temperatures at Saratoga and at the Isolated Spring as compared to the Spring at Bath in Tecopa Valley. ► Intersecting faults at hot springs. ► Water temperature from mixed deep circulation and river water. ► Local stress field determines fracture permeability.