CONTRIBUTION OF IMAGE FUSION BY HIGH PASS FILTER TO THE MAPPING OF FRACTURES IN THE TOUMODI DEPARTMENT, CENTRAL CÔTE D’IVOIRE

Toumodi department is facing challenges in accessing potable water due to the drying up of the water reservoirs used to meet the needs of population during dry seasons, a very high failure rate of catchment facilities (wells and boreholes), and their deficit in rural areas. However, the area lies in a basement zone where water is trapped in fractures. Various studies have shown that these fractured aquifers can represent significant groundwater reserves. In order to map the fractures of the geological formations of Toumodi department, to identify, if possible, groundwater potential, optical and radar sentinel images were merged.The pre-processing phase involved Sentinel 1A data encoding, mosaicking and Geometric Correction. The processing steps are optical and radar images fusion using a high-pass filter, the enhancement of discontinuities using Sobel-type directional filters and the extraction of lineaments. The results show more than 1,500 structural lineaments recorded, with an average length of 2.38 km. Validated by previous work and boreholeyield data, around 353 fractures were identified as major fracture, each exceeding 4km in length, these fractures are grouped into 5 orientation classessuch asN20-N30, N30-40, N40-50, N130-140 and N140-N150. These directions should expect to guide future drilling.