An updated earthquake probability map released Friday shows an increased likelihood of strong temblors striking the Kanto region surrounding Tokyo, based on findings made after the devastating March 2011 megaquake that rocked Tohoku.
The map said the probability of a strong quake of "lower 6" or more on the Japanese seismic intensity scale to 7 occurring in the next 30 years had climbed 31 points from 2010 to an estimated 62.3 percent for Mito, Ibaraki Prefecture, 90 km northeast of Tokyo.
The probability also rose by 11.9 points to 75.7 percent for the city of Chiba, by 4.1 points to 71.0 percent for Yokohama, by 4.9 points to 27.3 percent for the city of Saitama, and by 3.6 points to 23.2 percent for Tokyo.
Among major cities, Shizuoka posted the highest probability, of 89.7 percent, though down 0.1 point from 2010.
The high probabilities off Ibaraki and other zones were taken into account after the March 2011 Great East Japan Earthquake, according to the government's Earthquake Research Committee, which made the map that took effect last Jan. 1.
The probabilities for some locations were underestimated before the disaster, it said.
Regions with higher probabilities should further enhance disaster-preparedness efforts, the committee said.