Discussion and reply: Reply to the discussion

Revil (2013) contests that the depth from extreme points (DEXP) method could be used to interpret self-potential (SP) data, mainly because he thinks it is incompatible with the physics of SP signals and the specific boundary conditions. However, any reader of our paper would wonder why such an incompatible theoretical ap- proach could work so well: We in fact presented three synthetic cases and three real cases in which the method yields good results, which are also well consistent with the known information. This happens because our approach, contrarily to what is stated by Revil (2013), is physically consistent, based on the same theoretical framework of a number of already published papers (e.g., Bhatta- charya and Roy, 1981; Gibert and Pessel, 2001; Abdelrahman et al., 2008; Agarwal and Srivastava, 2009; Srivastava and Agarwal, 2009; Mauri et al., 2010; and many others). In addition, we find much of the comment does not sufficient consider the new theoreti- cal and practical aspects emerging in our and other imaging meth- ods (e.g., Fedi and Pilkington, 2012).