Scientists Record Major Seabed Subsidence in Indian Ocean

A research team operating an underwater observatory on the Southeast Indian Ridge documented a dramatic seabed collapse in the Indian Ocean. Starting on 26 April 2024, a swarm of small to strong earthquakes signaled a magma intrusion (magmagang) that caused the seafloor to drop by about 1.2 m within an hour and continue sinking to a total of 4.2 m over six days.

The observatory, positioned at a depth of roughly two kilometres on the edge of a rift valley, used a network of hydrophones, acoustic ranging devices and pressure sensors to capture simultaneous horizontal and vertical movements of the crust. The findings, published in *Nature*, represent the first direct measurement of such a rapid subsidence on the deep ocean floor and suggest a shallow magma reservoir was rapidly drained, creating a volume loss that pulled the overlying seabed downward.