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Experts update quake risk projections across Japan


Japanese seismic experts have updated their earthquake risk projections for the country's major cities over the next 30 years.

Members of the government's Earthquake Research Committee released the latest projection map on Friday.
They update the map every year.

Based on data of active faults and past major quakes in Japan, the experts calculated the probability of cities being hit by a quake with a minimum intensity of 6-minus. That's the 3rd highest level on the Japanese scale of zero to 7.

Cities on the coast of the Pacific Ocean where big earthquakes occurred repeatedly in the past and those near the Itoigawa-Shizuoka tectonic fault zone in central Japan are marked with high probabilities.

Compared with previous estimates, chances of strong tremors rose sharply in the Kanto region which includes Tokyo. Experts now believe that tectonic plates under the Kanto region are interacting at a depth much shallower than earlier estimated.

Yokohama City, south of Tokyo, now faces a 78 percent chance of a 6-minus or higher tremor within 30 years -- 12 percentage points up from the 2013 projection.

The figure for Chiba City, just east of Tokyo, stood at 73 percent, up 6 points. Mito City, north of Tokyo, was at 70 percent, up 8 points, and Saitama City at 51 percent rose 21 points.

The projection for central Tokyo rose 20 percentage points to 46 percent.

Cities with high estimated risks outside the Kanto region are Kochi City with 70 percent, Nemuro City 68 percent, Shizuoka City 66 percent, Osaka City 45 percent, and Nagoya City 43 percent.

The chief of the Earthquake Research Committee, Yoshimori Honkura, said people in cities with high risks urgently need to make buildings quake-resistant and lash down furniture to minimize damage.

He warned that cities with lower probabilities also need to prepare for a possible quake because the figures are relatively high compared with foreign countries.


    NHK WORLD News