Results from Scientific Drilling Expedition to be Discussed at 2013 AAAS Meeting
Boston, Mass – The immense, magnitude 9.0 Tohoku-Oki earthquake that struck Japan in March 2011 resulted in the largest fault slip ever recorded – more than 165 feet (50m). The movement also triggered a catastrophic tsunami, and taken together, the disasters claimed more than 19,000 lives.
New research from the Integrated Ocean Drilling Program (IODP) has yielded important insights into the nature of this event. One notable finding, published in the February 8 issue of Science, suggests that the fault released almost all of its accumulated stress during the quake. This marks the first time a near-complete stress drop has been recorded by direct measurement shortly after an earthquake.
Scientists involved with the project will gather to discuss this and other preliminary findings at the 2013 Annual Meeting of the American Association for the Advancement of Science (AAAS) in Boston. The session, titled “Finding the Fault: Sampling the Source of the M9.0 Tohoku Earthquake,” will take place on Sunday, February 17, at 8am in Ballroom A of the Hynes Convention Center.
The project, known as IODP Expedition 343 (Japan Trench Fast Drilling Project) set out almost exactly a year after the quake to drill core samples from the fault and make measurements inside the resulting boreholes. A follow-up expedition in summer of 2012 returned to install a long-term temperature observatory designed to measure residual frictional heating.
Such a rapid mobilization (less than 13 months) is unusual for a large-scale, international project of this nature. However, many of the geophysical signatures of such an event are highly time-dependent, which made it critical to access the fault before these signals faded. In the process, the team broke several records for scientific ocean drilling, penetrating about half a mile (856m) below the sea floor in more than four miles (6912m) of water depth.
Sunday’s AAAS session will feature:
- “Overview of the Tohoku Earthquake: 50-m Fault Slip Reaching the Deep Sea Trench”
Shuichi Kodaira, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
- “Defining the Structure of the Earthquake Fault by Geophysical Logging and Coring”
Frederick Chester, Texas A&M University
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- “Borehole Observatory and Geophysical Measurements”
Emily Brodsky, University of California, Santa Cruz
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All three speakers will be onsite in Boston on Saturday, February 16, and available to answer questions from the news media. For additional assistance, please contact:
Matthew Wright, Consortium for Ocean Leadership