Studies show that the Tokyo metropolis has an increasing earthquake frequency after the disasters that hit Japan in March 2011. The group of researchers, headed by professor Shinji Toda of the Tohoku University, found that Tokyo recorded an earthquake frequency with at least a magnitude of 3. It was higher than the recorded findings prior to the 2011 Great East Japan Earthquake.
Even after having hit by a massive quake, an area is expected to return to its previous frequency record after two to four years. In the case of Tokyo, it has shown to be slower. Chiba and Kanagawa Prefectures both showed the same slow return to normal frequency. Based on the research led by the Tohokudai professor, on average, Tokyo only recorded a frequency of one earthquake a week prior to the 2011 great temblor. However, in December of last year, the quake frequency in Tokyo had become once every two or three days.
Tokyo’s quake frequency with a magnitude of 3 or higher on a regular basis makes it, and possibly the surrounding area, more likely to get hit by an earthquake with a magnitude of 7 or higher in the future. Chiba is also likely to suffer the same in the next five years, based on the studies. “There is a possibility that a phenomenon that cannot be expected after a regular earthquake, may be happening,” professor Toda said in alarm. Given the population density and number of infrastructures in Tokyo, the capital is in an alarming risk of suffering from an earthquake. The research proves it, not to mention Japan’s geographical location and nature.
[via Kyodo]