A Semi-Quantitative Approach to Detect Aquifers in Hard Rocks from Apparent Resistivity Data

Resistivity sounding technique is conventionally adopted for ground water exploration in hard rock areas. From the interpretation and layer parameter evaluation alone, deciphering the actual depth to aquifer zone and delineating the thin high yielding fracture zones is found to be difficult. In many cases, the high yielding zones are found to be well within the bedrock signal part of the sounding curve. A non-conventional way of examining the apparent resistivity data of soundings was attempted for the soundings conducted over different hard rock terrains. The interpretation yielded a factorial depth relation with the yielding aquifer zones hidden in the bedrock signal. This approach has been used successfully in many areas of investigation. A theoretical base for the observed depth relation is at developmental stage.