New satellite analysis has uncovered evidence of two previously unrecognized magma sources beneath Nicaragua's Masaya volcano, a popular tourist site near Managua. The finding comes from six years of Sentinel-1 radar observations processed with InSAR, which detects tiny rises and falls in the ground surface. The research was published in Geophysical Research Letters.
Between 2018 and 2024, one part of the caldera gradually subsided and then began to rise, a change the scientists interpret as fresh magma entering a deep reservoir. At the same time, the ground around the active Santiago crater and its lava lake kept sinking, suggesting a separate, shallower magma reservoir was behaving differently. This split behavior implies the volcano's underground plumbing is more complex than previously known.
About two million people live within 13 miles of Masaya, and the volcano is a national park. It last produced a major lava flow in 1772, but its persistent degassing can release harmful sulfur dioxide. The authors say continuous monitoring, like the satellite-based approach used here, is essential for distinguishing normal activity from changes that could signal a future eruption.