Magma Storage Below Sabancaya Volcano (Southern Peru) Imaged by Broadband Magnetotellurics

Abstract Sabancaya volcano is one of the most active volcanoes in the Central Andes. Its ongoing eruptive process is accompanied by large‐scale deformation, with activation of the Huambo‐Cabanaconde fault system, marked by intense seismicity over an area of about 50 × 30 . We present a pilot magnetotelluric survey performed in 2022, covering the Ampato‐Sabancaya complex, Hualca‐Hualca volcano, as well as the related system of normal faults. Our three‐dimensional electrical resistivity model reveals pronounced vertical gradients and lateral contrasts at elevations above sea level, along with generally low resistivity values at depth. Seismicity at depths km below sea level predominantly occurs in a low resistivity environment: 90% of seismic events occur at resistivity values below 10 m. Two prominent electrical conductors (