© Kyodo Graphic
Kyodo - An active fault around 200 km long that is believed to have been a source of huge quakes in the past has been found off Honshu's Kii Peninsula, according to researchers at the University of Tokyo.
If the fault on the Nankai Trough moves, it could trigger a magnitude 8.0 earthquake, the researchers said, adding they have found a seabed cliff several hundred meters high that was created by the fault's past movements.
"There is a high probability that fault shifts have caused great tsunami," said Park Jin Oh, associate professor of marine geology. "We need to reformulate disaster countermeasures by taking into account an active fault on the seabed 200 km or longer."
Park analyzed sonar data on the seabed collected by the Japan Agency for Marine-Earth Science and Technology and found a fault branching off from a boundary between two tectonic plates in an area west of the southern tip of the Kii Peninsula in Wakayama Prefecture.
The fault was found to be connected to a similar fault to the east of the peninsula and to extend at least 200 km, the researchers said.
