This “decoupling” process, inwards which the edges of ii tectonic plates that are frictionally locked together piece of cake became unstuck, transferred stress to side past times side sections that were notwithstanding locked. As a result, the quake, which was the virtually powerful e’er recorded to hitting Japan, may own got occurred before than it powerfulness own got otherwise, said Andreas Mavrommatis, a graduate pupil inwards Stanford’s School of globe Sciences.
Mavrommatis too his advisor, Paul Segall, a professor of geophysics at Stanford, reached their conclusions afterward analyzing fifteen years’ worth of GPS measurements from the Japanese isle of Honshu. Their results were published before this yr inwards the journal Geophysical Research Letters.
“We looked at northeastern Japan, which has 1 of the densest too longest running high-precision GPS networks inwards the world,” Mavrommatis said.
Segall said, “The measurements indicated the plate boundary was gradually becoming less locked over time. That was surprising.”
The scientists volition introduce their work, “Decadal-Scale Decoupling of the Nippon Trench Prior to the 2011 Tohoku-Oki Earthquake from Geodetic too Repeating-Earthquake Observations,” Dec. 17 at the American Geophysical Union’s Fall Meeting inwards San Francisco. The speak volition own got house at five p.m. PT at the Moscone Convention Center inwards Moscone South, Room 306.
The pair’s hypothesis is farther supported past times a recent analysis they conducted of so-called repeating earthquakes offshore of northern Honshu. The minor quakes, which were typically magnitude iii or 4, occurred along the entire length of the error line, merely each 1 occurred at the same location every few years. Furthermore, many of them were repeating non at a constant merely an accelerating rate, the scientists found. This acceleration would hold out expected if the error were becoming less locked over time, Mavrommatis said, because the decoupling procedure would own got relieved pent-up stress along around sections of the error merely increased stress on side past times side sections.
“According to our model, the decoupling procedure would own got had the final result of adding stress to the department of the error that nucleated the Tohoku quake,” Segall said. “We suspect this could own got accelerated the occurrence of the earthquake.”
The scientists caution that their results cannot hold out used to predict the occurrence of the following major earthquake inwards Japan, merely it could shed lite on the physical processes that operate on faults that generate the world’s largest quakes.