Indian Ocean seabed drops several meters after magma intrusion

Scientists recorded a rapid subsidence of the seabed in the Indian Ocean, where the ocean floor sank up to 4.2 meters within six days. The event began on 26 April 2024 with a swarm of small to moderate earthquakes along the Southeast Indian Ridge. An underwater observatory situated about two kilometres deep at the edge of a rift valley, equipped with hydrophones, acoustic rangefinders and pressure sensors, captured the horizontal shift, vertical drop and accompanying seismic activity simultaneously.

The researchers interpret the pattern as a magma intrusion, indicating that a shallow magma reservoir drained, causing a loss of volume beneath the crust and the observed subsidence. The findings, published in *Nature*, represent the first direct, high‑resolution measurement of such a process on the deep‑sea floor, expanding understanding of submarine volcanic dynamics.