An application of magnetotelluric data inversion in a stratovolcano region

Sabalan, with an elevation of 4,811 meters, is the second-highest mountain located in the Alborz mountain range in northwestern Iran. Although it is an inactive stratovolcano, the overall system of faults around the Sabalan peak can be considered as two common groups of linear and arcuate faults. Faults with the linear structure are mainly observed along with the NW-SE and N-S directions at the southern part of Sabalan. Arcuate faults around the Sabalan volcano are almost coincided with the crater of the volcano and have led to the penetration of volcanic masses. In this study, magnetotelluric data modeling was performed on one profile (“namely the MM profile”). The profile includes both types of fault systems in the region. By assessing and interpreting the resistivity section of the MM profile by 2D magnetotelluric data inversion, we have clearly detected the faults by features such as displacement and sudden changes in resistivity anomalies forming conductive zones with low resistivity anomaly along with the profile. The MM profile has almost continuous conductive anomaly (<30 Ω-m) between elevations of 1000 to 3000 m except in the eastern side, where a resistive block is found from the surface down to lower depths. Eight faults were detected across the MM profile. Our final represented geology section is consistent with actual observations and 2D magnetotelluric data inversion and prior studies.