**1. Introduction**

Localization of ground water is a national and global issue at the priority basis. The fragility of water for various uses is a serious problem, which can be resolved by geological and Vertical Electric Soundings (VES) studies [1–3]. The problem arises when the geological information is not enough and accurate in the location of wells, resulting into dry wells. This problem is mostly frequent in volcanic areas, where the areas covered by alluvial material do not allow to observe the possible structures that contain underground water. In this study, we present a methodology for the location of this resource in arid volcanic zones, especially in the Central Mesa of Mexico. The methodology is based on a basic knowledge of Geology, the study of the magnetic field (air and ground) and the application of the electrical resistivity method, in two modalities, that is, sections and SEV [2].

The methodology was applied to solve serious water problem in the rural population of La Dulcita town, Municipality of Villa de Ramos, which is located at the Northwest of the capital of San Luis Potosí and state of Zacatecas (**Figure 1**). The population of La Dulcita in 2005 was reported with 750 inhabitants [4] and their water was supplied by a single well located at 5 km South of La Dulcita town, with

#### **Figure 1.**

*Satellite image of study area, that is, La Dulcita, villa de Ramos, state of San Luis Potosí, Mexico.*

its capacity measured less than 1 L/s, which was not sufficient for the entire population. In addition, the State Water Commission (CEA, for its acronym in Spanish), State of San Luis Potosí, had drilled three wells and all of them were dry.

The rocks that form the aquifers are characterized by their physical properties such as porosity, permeability and water content [5, 6]. The present methodology allows locating the zones and the degree of fracture and measure if these can be associated to moisture from the surface.
