Overview
- A network of more than 20 seafloor instruments recorded a full seafloor‑spreading episode, giving the first in situ time series of earthquakes, large displacements, subsidence and temperature change.
- The sequence began with an earthquake swarm that, on 26 April 2024, triggered dike intrusion and faulting and led to about 4.2 metres of axial subsidence over six days.
- Instruments and ship‑based mapping show opposing crustal blocks shifted roughly 2–4 metres and roughly 150–160 million cubic metres of lava were emplaced on the seabed.
- Modelling of millions of scenarios by the team best fits a collapse or draining of a deep magma sill, rapid magma injection into dikes, and substantial aseismic fault slip that outpaced recorded earthquakes.
- The results reconcile a long-standing gap between earthquake catalogs and long‑term plate motion by showing much plate separation can occur silently, and they point to wider use of targeted seafloor observatories to track oceanic crust formation.