Experimental Design of Parallel 3D Geoelectric Measurements

We have developed ETH DCMES II, a new, fully distributed, smart electrode geoelectric data acquisition system that allows parallel measurements to be performed efficiently. This is an important prerequisite for a novel data acquisition concept that encompasses two main aspects. Firstly, roll-along strategies can be employed to cover a large virtual grid with a limited number of electrodes. Secondly, within each electrode deployment, pole-bipole measurements can be acquired efficiently using the parallel recording capabilities of ETH DCMES II. For a set of n electrodes only 2n parallel pole-bipole scans (using 2 variable reference electrodes) are required to reconstruct any other pole-bipole configuration, even in the presence of noise. The performance of the system is demonstrated with a field experiment over a former waste disposal site in Switzerland. The 3D data set of several hundred thousand measurements could be acquired in about 7.5 hours, which allowed critical features within and outside of the waste pits to be delineated.