Estimation of geothermal parameters using spectral analysis and 3D inverse modelling of the magnetic data in the Mahallat geothermal field

The existence of hot springs, extensive travertine deposits, hydrothermal alteration ranges, and the presence of faults in the Mahallat indicate an important geothermal system. In order to recognize the reservoir of the geothermal system as well as areas with magnetic anomalies, in the study area were conducate the magnetometry measurements In the length of 10 profiles,with total length 160 km and with an station spacing of 40 meters. The main purpose of this study is to estimate the bottom (Curie point depth) and top depth of magnetic sources also thermal gradient and heat flow using spectral analysis (centroid method). As well as conducted 3D inverse modeling of the magnetic data by Li-Oldenberg algorithm, in order to determine of geometries of the heat source. Conformity between of the obtained results by inverse modelling and centroid method indicate the existence of geothermal reservoir in the north part of study area. The results indicated that the range of variations in the bottom- depth, top depth of magnetic sources, varies from 1350 to 3400 meter,1230 to 2390meter, respectively.