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

We analyze 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 towards 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 ~3210 m, and a volume change of ~-1.3x106 m3 in Period 1 and ~4.5x105 m3 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.