Access

News and Views

Nature 424, 893-894 (21 August 2003) | doi:10.1038/424893a

Open Innovation Challenges

Earth science: Tiny triggers deep down

Harry W. Green, II1

Top

The documentation and characterization of remotely triggered earthquakes deep within the Earth is an achievement that provides insight into the mechanisms that initiate such events.

Earthquakes occur widely in the planet's crust and to depths approaching 700 km in subduction zones, where oceanic crust and the associated 50–100 km of mantle dive back into Earth as the return flow of plate tectonics. But we know little about the physics of earthquake initiation (nucleation), especially at great depth, because the mechanisms known to operate close to the surface — brittle failure of virgin rock, or frictional sliding on a pre-existing fault — cannot occur at the high pressures at depth1.

  1. Institute of Geophysics and Planetary Physics, and the Department of Earth Sciences, University of California, Riverside, California 92521, USA.
    Email: hgreen@mail.ucr.edu