Overview
- A study in Geophysical Research Letters identifies an approximately 20‑kilometer layer between Bermuda’s oceanic crust and the upper mantle.
- The layer is about 1.5% less dense—roughly 50 kilograms per cubic meter—than surrounding mantle, a contrast the authors say can support the bathymetric swell without an active plume.
- Researchers analyzed seismic waves from 396 distant earthquakes recorded at Bermuda’s permanent station to image structures to roughly 50 kilometers depth, with limited lateral coverage.
- The feature is interpreted as underplated material emplaced during or soon after volcanism 30–35 million years ago, with a plausible lateral extent of 50–100 kilometers and an extreme upper limit near 200 kilometers.
- The team plans follow‑up studies at other islands to assess whether similar thick underplating exists elsewhere or if Bermuda is unique.