Integrated Geological, Geophysical Data and Geographic Information System (GIS) for Better Mapping of Geothermal Potential Zones

This study delineates hydrothermal (hot-water) geothermal potential zones in the central–western Taiz region, Yemen, by integrating remote sensing, geological, and aeromagnetic data within a geographic information system (GIS). Nine controlling factors were used: elevation; drainage density; lineament density; geological fault density; lithological contact density; rock units; and the densities of faults interpreted from aeromagnetic data at depths of 38.3, 95.5, and 144.4 m. Each factor map was reclassified, and class weights (0–5) were derived from the number of eight known hydrothermal occurrences falling within each class. The weighted maps were combined with a weighted overlay technique and classified into five potential classes. Very high and high potential zones cover 5.08% and 9.65% of the study area, respectively, and follow fault- and lineament-rich corridors. Seven of the eight known occurrences (87.5%) fall within the very high potential zone, and a success-rate analysis gave an area under the curve (AUC) of 0.81. Because the same eight sites were used for weighting and evaluation, these statistics indicate internal consistency rather than independent predictive accuracy. Lineaments, geological faults, and shallow magnetic faults showed the greatest spatial overlap with the high-potential zones. As no heat-flow, geothermal-gradient, or subsurface-temperature data exist for the area, the mapped zones are potential targets inferred from indirect indicators that require confirmation by temperature-gradient measurements, heat-flow studies, and exploratory drilling. The study is limited to hot-water-dominated systems.