Geophysicists have obtained detailed three-dimensional images of a dangerous megathrust fault west of Costa Rica where two plates of the Earth’s crust collide.
In this perspective view of the shallow megathrust fault, looking seaward towards the trench, the frontal prism has been cut away. The color scales indicate depth below seafloor, and grey denotes the seafloor. (Image credit: Edwards et al., Nature Geoscience, Feb-2018)
The images reveal features of the fault surface, including long grooves or corrugations, that may determine how the fault will slip in an earthquake.
The study, published February 12 in Nature Geoscience, focused on the Costa Rica subduction zone where the Cocos plate slowly dives beneath the overriding Caribbean plate. Variations in texture seen in different portions of the fault surface may explain why