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Item type:Publication, Locating active faults in the Cusco Valley using magnetotelluric and radon gas data(RELX Group (Netherlands), 2024-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Magnetotelluric images of the hydrothermal and magmatic system beneath Volcan Misti (Peru)(Elsevier BV, 2026-07-01)Volcan Misti, situated in the Central Volcanic Zone (CVZ) is considered one of the most hazardous volcanoes in South America. Petrophysical and mineralogical studies of the erupted materials inferred the presence of an interactive and stratified magmatic system, composed of two to three magma reservoirs. However, its geometry and the relationships with tectonic and seismic activity remain largely unresolved due to the lack of high-resolution geophysical imaging. To address this question, 42 broadband magnetotelluric (MT) stations were deployed around the volcanic edifice to construct the first three-dimensional electrical resistivity model of the magmatic and hydrothermal system. The data were inverted and the resulting model was characterized by three low-resistivity features. The first is a conductive layer, ∼1 km thick (5 to 40 Ωm), that extends laterally beneath the volcanic edifice and is interpreted as a clay cap. The second feature corresponds to an inferred low-resistivity body (10–30 Ωm), located at sea level. The third is a low-resistivity body (< 10 Ωm) imaged at ∼10 km below sea level, located slightly east of the volcano (∼2.5 km). The resistivity of this feature is interpreted as indicative of the presence of andesitic melts, suggesting a melt fraction in the range 4–24% for the temperature range 900–950 °C. The seismicity associated with the volcano is minimal and concentrated just beneath the crater at a depth of ∼2.5 km. The shallow depth of the seismicity, together with the MT model, suggests that the recharge and supply of magma occur in a cryptic manner. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Magma Storage Below Sabancaya Volcano (Southern Peru) Imaged by Broadband Magnetotellurics(Wiley, 2026-02-01)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 (<0.5 and 2–4 m) are imaged at depths 11–18 km and 3–8 km, respectively. Using petrological constraints, we interpret them as the signature of the magmatic plumbing system, connecting the Hualca‐Hualca and Ampato‐Sabancaya volcanoes. The deeper conductor is inferred to represent a magma reservoir situated beneath the older Hualca‐Hualca volcano, consistent with long‐term deformation and seismicity. It is connected to the laterally offset shallow magma chamber below Sabancaya. At depth 2–10 km, a strong conductor (<0.1 m) is imaged in the Huambo‐Cabanaconde fault zone. The extremely high conductivity of this body is attributed to the abundance of ultra‐saline brines, originating from the deep magma reservoir below. We speculate that the strong seismicity cluster detected in 2013 facilitated the passage of magmatic fluids exsolved from the magma reservoir, and replenished this ultra‐conductive body.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Locating active faults in the Cusco Valley using magnetotelluric and radon gas data(Elsevier, 2025)This study presents a novel approach to identifying and characterizing active faults in urban areas, using an example from the city of Cusco in Peru, by combining magnetotelluric (MT) exploration and radon gas monitoring. The research aims to improve understanding of the active faults in the Cusco Valley by using the MT method to provide subsurface electrical resistivity data, enabling the mapping of fault structures and determination of fault properties. A 2-D inversion of the MT data resulted in resistivity models that revealed critical information about fault geometry, such as dip and depth. Radon gas measurements complement the MT data by being able to distinguish between active and inactive faults. This is because active faults can exhibit higher permeability due to ongoing tectonic activity. This increased permeability facilitates the migration of radon from deeper rock formations to the surface, leading to detectable anomalies. Active faults are particularly significant as their continued deformation enhances permeability, making radon anomalies a valuable indicator for locating these structures. A clear correlation was found between elevated radon concentrations (>5.9 kBq m−3) and the locations of faults identified through the MT resistivity model, and additional gas sample analyses ruled out the possibility that these anomalies were caused by lithological variations. This integrated approach holds significant potential for detecting active faults in urban areas such as Cusco. In these locations faults such as the Cusco and Alto Qosqo faults may be obscured by construction. The findings uncovered previously unmapped fault lineaments and advanced the understanding of fault kinematics in Cusco, emphasizing the importance of combining MT and radon monitoring for earthquake hazard assessment in urban environments.1