On March 11, 2011, the subduction plate boundary under northern Japan ruptured in a M9.0 megathrust earthquake. The earthquake rupture displayed some very unusual characteristics. The offset between the overriding and subducting plates was measured as ~60 m at the seafloor, more than twice the previous record for displacement in a single event! This great displacement, along with slowing of the rupture as the earthquake grew toward the surface, contributed to the production of a very large tsunami.
One year after the earthquake, the drilling vessel Chikyu sailed to the Japan Trench with 27 scientists from 14 countries to drill through the seafloor to sample the plate boundary fault (International Ocean Discovery Program Expedition 343). We recovered geophysical logs, thermal measurements, and core samples of the accretionary wedge, the downgoing Pacific Plate sediments, and the amazingly thin and slippery megathrust clays. My role on the expedition was “XCT Watchdog”, examining X-ray CT scans of the core as it came on board the ship to identify important deformation structures and distribute samples to the other specialist teams.
In this talk Dr. Rowe will describe the M9.0 earthquake and explain how it was different than most of the M9.0 earthquakes of the 20th and 21st centuries. Dr. Rowe will show some of the laboratories on D/V Chikyu and explain how science is done at sea on a big drilling vessel. Finally, Dr. Rowe will show the data collected on the expedition and present our explanation for the unusual Tohoku Earthquake.
Tuesday, December 12, 2017
4:00-5:00 PM EST | Show in my time zone
Christie Rowe is from northern California, her first pet rock was an actinolite-talc schist and she still has it. Dr. Rowe was 11 when the M6.9 Loma Prieta Earthquake suddenly impressed on her that humans are small and temporary and thereby started her on... Read More