Double Trouble: Two Active Magma Reservoirs Identified at Masaya Volcano, Nicaragua, Using Satellite Geodesy

Abstract We analyze and model ground deformation at Masaya volcano, Nicaragua, using Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) time series spanning January 2018–February 2024. Time series show the Masaya Central Reservoir (MCR) experienced ∼3 cm of line of sight (LOS) displacement away from the satellite north of the Santiago crater from 2018 to mid‐2022 (Period 1), followed by movement toward the satellite from mid‐2022 to 2024 (Period 2), interpreted as inflation of the MCR due to new magma supply from depth. Using a point‐source (“Mogi” model), our geodetic inversions identify a preferred source location of the approximate center of the Masaya caldera, a depth of ∼3,200 m, and a volume change of ∼−1.3 × 10 6 m 3 in Period 1 and ∼4.5 × 10 5 m 3 in Period 2. Throughout 2018–2024, the area around the active Santiago crater consistently showed motion away from the satellite, attributed to a second deflating shallower reservoir located at ∼200 m depth.