Magnetotelluric Case Study from Ain Al-Harrah Hot Spring, Al-Lith, Saudi Arabia

A couple of studies show that Saudi Arabia has promising geothermal resources. The most prominent sites are located around Al-Lith, with four hot springs, where Ain Al-Harrah has the highest temperature. Previous studies suggest that this hot spring’s geothermal reservoir is promising and may provide the Al-Lith region with long-term electricity. Our key objective is to investigate and explore more comprehensively the prospect of geothermal resources around the Ain Al-Harrah hot spring. To achieve this goal, we acquired broadband magnetotellurics (MT) data in the period range 0.001–60 s for three different sampling frequencies at 15 soundings along one profile. The 2D inversion results show three main units. A conductive anomaly (< 30 Ω.m) at a depth > 3.5 km below the surface is most likely related to a geothermal heat source. The high resistive zones (roughly 200–4000 Ω.m) are associated with hard-rock geological formations. Although uncertain, a detected medium resistive body (30–200 Ω.m) at a depth of 800 m below the surface possibly indicates the pathway of geothermal fluids forming a convection cell between the hot body and the surface. A lateral resistivity discontinuity is considered a fracture zone acting as a pathway for the fluids to reach the surface forming the hot spring.