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Lab Earthquakes Show How Grains at Fault Boundaries Lead to Major Quakes


By simulating earthquakes in a lab, Caltech engineers have provided strong experimental support for a form of earthquake propagation now thought responsible for the magnitude-9.0 earthquake that devastated the coast of Japan in 2011. "Our novel experimental approach has enabled us to look into the earthquake process up close, and to uncover key features of rupture propagation and friction evolution in rock gouge," says Vito Rubino, research scientist and lead author of the Nature paper. The Nature paper is titled "Intermittent lab earthquakes in dynamically weakening fault gouge." Rubino and his co-authors Nadia Lapusta, Lawrence A. Hanson, Jr., Professor of Mechanical Engineering and Geophysics, and Ares Rosakis, Theodore von Kármán Professor of Aeronautics and Mechanical Engineering, show that so-called "stable" or "creeping" faults are not actually immune to major ruptures after all, as previously suspected. [Caltech story]

Tags: research highlights GALCIT MCE Ares Rosakis Nadia Lapusta Vito Rubino

How Friction Evolves During an Earthquake


Professor Ares Rosakis, and colleagues including Professor Nadia Lapusta and Research Scientist Vito Rubino, are studying the way friction changes along a fault during a seismic event by simulating quakes in a lab. "Our unique facility … allows us for the first time to study friction point-wise and without having to assume that sliding occurs uniformly, as is done in classical friction studies," Rosakis explains. Professor Lapusta adds, “some numerical models of earthquake rupture … have used friction laws with slip-velocity dependence… It is gratifying to see those formulations validated by the spontaneous mini-earthquake ruptures in our study. " [Caltech story]

Tags: research highlights GALCIT MCE Ares Rosakis Nadia Lapusta Vito Rubino