Slippery fault unleashed destructive Tohoku-Oki earthquake and tsunami

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Posted on December 10, 2013
Slippery fault unleashed destructive Tohoku-Oki earthquake and tsunami

UCSC researcher Patrick Fulton is shown with core samples from the drilling operation. Credit: IODP
For the first time, scientists have measured the frictional heat produced by the fault slip during an earthquake. Their results, published December 5 in Science, show that friction on the fault was remarkably low during the magnitude 9.0 Tohoku-Oki earthquake that struck off the coast of Japan in March 2011 and triggered a devastating tsunami.

“The Tohoku fault is more slippery than anyone expected,” said Emily Brodsky, a geophysicist at the University of California, Santa Cruz, and coauthor of three papers on the Tohoku-Oki earthquake published together in Science. All three papers are based on results from the international Japan Trench Fast Drilling Project (JFAST), which Brodsky helped organize.

Because friction generates heat (like rubbing your hands together), taking the temperature of a fault after an earthquake can provide a measure of the fault’s frictional resistance to slip. But that hasn’t been easy to do. “It’s been difficult to get this measurement because the signal is weak and it dissipates over time, so we needed a big earthquake and a rapid response,” said Brodsky, a professor of Earth and planetary sciences at UCSC.

Read more at: Phys.org