Transform boundaries neither create nor consume crust. Rather, two plates move against each other, building up tension, then releasing the tension in a sudden and often violent jerk. This sudden jerk ...

A hidden shard of ancient crust has been detected where California’s San Andreas system collides with the Cascadia subduction zone, reshaping how I understand the tectonic engine of the West Coast.

The solid ground that we all live on forms a thin crust around the Earth. It’s no more than 50km thick - and it’s just the upper part of the lithosphere. Below it is the upper mantle. It’s mostly ...