Scientists have discovered strong variation in the tectonic plate stresses in Nankai Trough, a region off the Pacific coast of Japan, which is notorious for generating devastating earthquakes and tsunamis.
Scientists aboard the new scientific drilling vessel Chikyu made the finding.According to a report in ENN, for the research, the team collected physical measurements and images using advanced borehole logging technology by drilling deep into the zone responsible for past and likely future tsunamis.
The entire course of action involved drilling holes ranging from 400 to 1,400 meters below the sea bed to study conditions in the boundary plate region.
“The rock caught up in the tectonic plate boundary is literally falling apart as a result of the intense stresses of tectonic plate convergence,” said co-chief scientist Harold Tobin, associate professor of geology and geophysics at the University of Wisconsin-Madison.
“By drilling a transect spanning the area of tsunami generation, we found that the region that lies above the earthquake-producing zone exhibits very different stress conditions than other parts of the plate boundary.” ENN quoted co-chief scientist Masataka Kinoshita, as saying.
“Caught in the vise between two converging rigid tectonic plates, the wedge was found to be undergoing strain in preparation for the next earthquake,” he added.
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NanTroSEIZE is expected to continue until 2012, with the ultimate objectives of drilling across the plate boundary fault responsible for magnitude 8 earthquakes to sample the rocks and fluids in the fault, and to place instruments within it to monitor activity and conditions leading up to the next great earthquake.
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