The study area is located in the extreme southwest of the Ougnat Mountains in the eastern Anti-Atlas, which is part of the distorted northern margin of the West African craton. It has Late Neoproterozoic to terminal, Paleozoic and Quaternary lands. In order to obtain a better recognition of the different structural contacts and to define the alignment of mineralized veins in barite and galena at the level of the study area, we used the technique of electrical tomography. The resulting response, in the form of electrical imaging, informed us in detail about the different zones of heterogeneity existing in the prospected soil. In induced polarization, the pseudosections obtained were able to locate the passages of the zones of anomalies encountered and thus confirm their alignments defined by the electrical resistivity measurement results.

Resistivity Profiling and Very Low Frequency (VLF) electromagnetic methods were introduced to study fracture zones detection in Zaouia Jdida locality, within the Errachidia basin. The Horizontal Profiling was conducted in Wenner-α array, with AB = 300 m and profile lines oriented NW-SE and NE-SW. The resistivity measurements were taken using MAE advanced geophysics instruments. The VLF profiles were implanted with the length reaches 1000 m and profile lines oriented in NE-SW direction. The VLF measurements were collected using T-VLF iris instrument and the data filtering was done using KHFFILT software. Two filters, Karous-Hjelt and Fraser, were applied to the real component of the secondary electromagnetic field. The qualitative interpretation of resistivity results, showed the presence of subsurface targets; fracture zones were detected at 70m, 240m and 450m positions along the profile P1, at 180m, 340m and 450m positions from the profile P2. The semi-quantitative interpretation of VLF results revealed the presence of two principal fracture zones at L3 and L5 locations, oriented NW-SE, at a depth range of 30 m to 60 m. The VLF anomaly observed at L3 location is confirmed by the resistivity measurements from the profile P1 (at 70m station). The identified fractures represent the potential zones for groundwater supply and then will have an implication on storage and movement of groundwater in the prospect area.

This work is the results of a geophysical study by geoelectric method, 62 electrical soundings of an injection line length of AB=1000m with continuous electrical current, its goal is to identify the main areas fractured by which is performs the preferential flow in depth and subsurface from plateau to plain of Saiss and to have an idea about the geometric of the existing aquifer. After the interpretation of all data of vertical electrical drillings, we exploited to make a quantitative and qualitative interpretation of the results. Indeed we have established apparent resistivity maps, isohypse of the resistant roof, isopaque card of Liassic limestones also geoelectric cuts in correlation with data from existing drilling on the study area Résumé : Le présent travail fait les résultats d'une étude géophysique par méthode géoélectrique, comporte 62 sondages électriques d'une longueur de ligne d'injection du courant électrique continue AB= 1000m, son but principal est de repérer les grands axes fracturés par lesquels s'effectue la circulation préférentielle des eaux en profondeur et en subsurface, du Causse vers la plaine de Saiss ainsi d'avoir une idée sur la géométrique de l'aquifère existant. Après l'interprétation de l'ensemble des données des sondages électriques verticaux réalisés, nous avons bien y exploités pour faire une interprétation qualitative ainsi quantitative des résultats obtenus. En effet nous avons établis des cartes de résistivités apparentes, d'isohypse du toit du résistant, carte d'isopaque des calcaires liasiques aussi des coupes géoélectrique en corrélation avec des données des forages existants sur la zone d'étude. Motsclés: Causse du Moyen Atlas, géoélectrique, sondage électrique, résistivité apparente.

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