Scientists calculate friction of Japan’s 9.0 earthquake in 2011, Dec. 11

An international team of scientists that installed a borehole temperature observatory following the 2011 Tohoku-Oki earthquake in Japan has been able to measure the “frictional heat” generated during the rupture of the fault – an amount the researchers say was smaller than expected, which means the fault is more slippery than previously thought.  It is the first time scientists have been able to use precise temperature measurements to calculate the friction dynamics of fault slip.  Results of the study have been published in the journal Science.  “This gives us some unprecedented insights into how earthquakes actually work,” said Robert Harris, a geophysicist at Oregon State University and co-author on the Science article. “No one really knows how much frictional resistance there is to slip and for the first time, this gives us some idea.  “The project itself was an engineering feat and an amazing one at that,” added Harris, who is a professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State. “To reach the fault, the team had to drill through 800 meters of the seafloor – at a depth of nearly 7,000 meters below the ocean’s surface. It pushed the limits of that technology as far as they can go.”  The study was funded by the Japan Agency for Marine-Earth Science and Technology, the Integrated Ocean Drilling Program, the National Science Foundation, and the Gordon and Betty Moore Foundation.