André Revil is Associate Professor at the Colorado School of Mines and Directeur de Recherche at the National Centre for Scientific Research (CNRS) in France. His research focuses on the development of new methods in petrophysics, and the development of electrical geophysical methods applied to geothermal systems, water resources and oil and gas reservoirs. Dr Revil is presently Chief Editor of the Journal of Geophysical Research – Solid Earth, Associate Editor of the Vadose Zone Journal and editorial member of the International Journal of Mathematical Modelling and Numerical Optimization and has published 156 peer-reviewed papers. He received the Bronze Medal from the CNRS for outstanding research in 2003 and an award of excellence from the American Rock Mechanics Association (ARMA) in 2004. Abderrahim Jardani is Associate Professor at the University of Rouen, where he also obtained his Ph.D. in geophysics in 2007. His research interests centre on environmental geophysics, mathematical modelling of hydrologic systems and inverse problems. Dr Jardani has authored twenty-seven peer-reviewed publications in the field of hydrogeophysics, especially in the theory of self-potential signals and its application to environmental problems. He is a member of the American Geophysical Union.