A new study led by McGill University has found that tectonic plates beneath the Earth’s surface can show varying degrees of roughness and could help explain why certain earthquakes are stronger than others.

Earthquakes happen when the rocks beneath the Earth’s surface break along geological fault lines and slide past each other. The properties of these faults - such as the roughness of their surface - can have an influence on the size of seismic events, however their study has been challenging because they are buried deep beneath the Earth’s surface.

In order to have a better understanding of the characteristics of these faults, researchers from McGill University, the University of California Santa Cruz and Ruhr University Bochum in Germany used high-resolution seismic reflection data to map and measure the roughness of 350 km2 of a plate boundary fault located off the Pacific coast of Costa Rica.

“We already knew that the roughness of a fault was an important factor, but we did not know how rough faults in the subsurface truly are, nor how variable the roughness is for a single fault,” says James Kirkpatrick, a professor in McGill’s Department of Earth and Planetary Sciences.

Read More: McGill University