Imaging subsurface northern Rahat Volcanic Field, Madinah city, Saudi Arabia, using Magnetotelluric study

Abstract Rahat volcanic field is one of the basaltic fields in Saudi Arabia that has three major geohazard events; the historical eruption (1256 CE), the fissure eruption (~4500–1500 BP), and seismic swarm (1999). These events were studied and evaluated using geophysical and geochemical studies as well as volcanological studies. Geophysical studies include gravity, seismic, and magnetotelluric surveys. In the current research, the magnetotelluric data will be analyzed using 3D inversion technique in order to image the subsurface resistivity setting of the study area. Results from 3D inversion of the MT data revealed four major resistivity structures. The first is a layer of intermediate resistivity (40–250 Ω-meters) which is thicker (~800 m) to the south-west and thinner to the eastern edge, mostly covered by exposed Precambrian basement. This layer is underlain by resistive (>1000 Ω-metres) granitic basement. Intruding into the resistive basement are two near-vertical conductive (