Experts weigh in on powerful Japan quake and urge vigilance against bigger ones

TOKYO – Several experts have weighed in on the

powerful earthquake on Dec 8

that triggered some tsunami along the Pacific coast in Japan’s north-east, urging vigilance against future quakes.

Dr Yoshihiro Hiramatsu, a professor at Kanazawa University and expert on earthquake studies, said the latest quake may be attributed to a tectonic plate that had yet to break during the massive 9.0-magnitude quake that hit the same region in 2011.

“Judging from the depth of the quake’s origin and the angle of the fault, it is believed to have occurred at the border area where the ocean-side plate sinks beneath the land-side plate on which the Japanese archipelago lies,” he said.

It could be described as having been caused by a tectonic plate that had yet to break because the quake occurred north of the area where the March 11, 2011, quake originated, Dr Hiramatsu said.

Noting that quakes with a magnitude of 8 or greater have occurred in the region previously, including in 1968 off Tokachi, Hokkaido, the professor urged continued caution. He said the latest quake may have shifted the balance in the ground, possibly laying the groundwork for a larger one.

Dr Takuya Nishimura, a professor at Kyoto University’s Disaster Prevention Research Institute, said there was no question that the latest quake was a so-called subduction zone earthquake, such as those that occur at the boundary between two plates in the Pacific.

He said strong shaking was observed because the quake occurred near the land, even though it was far below the surface. KYODO NEWS