NGWA Event and Education Recordings Archive

Used for aquifer location, the GF6 and a seismic source are used together to generate and collect a seismoelectric signal indicating aquifer depth, yield, and thickness. The seismic source is used to create a sound wave (pulse). When the sound wave moves through aquifers, the water in the aquifer moves relative to the rock formation. Ions in the water are dragged away from their partners bound to the rock and the electrical disturbance created travels to the surface at the speed of light and is detected by the antenna array. Each signal is separated in time from its neighbors by the propagation time of the down-going seismic pulse, showing unambiguous depth and thickness data, as with reflection seismic. The form of each signal gives information about the depth and thickness of the aquifer and this is used to estimate the yield from a water well drilled at the survey site.

In 2013 Kraemer adapted the seismoelectric system for deep investigations [PL14] and this new system has shown that because of the focused, radial symmetry of seismoelectric signals radiated by plane interfaces, deep signals are unexpectedly strong. We have observed signals, from hydrocarbon/water contacts, at travel times corresponding to depths of more than 1400 meters using only a small cartridge source onshore. The current version of the PL14 is capable of detecting oil/gas reserves to depths exceeding 2000 meters.