Article Abstract
During the March 11, 2011, Mw 9.1 Tōhoku-oki earthquake, the plate boundary fault slipped an astonishing 50 m or more, with the slip extending all the way to the seafloor within the Japan Trench. The result was a much larger earthquake and tsunami than expected as well as considerable devastation on land. The earthquake challenged our understanding of subduction zone mechanics but also presented an opportunity to resolve long-standing questions regarding the amount of frictional resistance faults exhibit during earthquakes, resistance that influences the amount of fault slip and associated tsunami hazards. Here we report on how scientific ocean drilling successfully allowed the measurement of frictional heating within the fault zone that ruptured during the Tōhoku-oki earthquake.