Jan. 17 marks the 10th anniversary of the Great Hanshin-Awaji Earthquake, which took the lives of more than 6,400 people. In the past decade, Japan's earthquake countermeasures have changed enormously. Its earthquake observation system has become more sophisticated. Together with general observation and research, studies have made progress in understanding the active faults that cause inland underground earthquakes.
The vicious power of an inland underground earthquake demonstrated itself once again in October's Niigata-Chuetsu Earthquake. Even when the total energy released is not so large, an earthquake of this type can cause violent jolting in a limited area. Since 2000 the government's Earthquake Research Committee has been calculating the long-term probability of an earthquake occurring in the 98 inland active fault zones of Japan. By the end of 2004 it had completed evaluation of 73 locations. At the same time, the committee has evaluated the probability of an undersea earthquake occurring in places such as off the Sanriku coast, the Boso Peninsula, and the Tonankai and Nankai sea areas.
On the basis of this evaluation, the committee by March will make public a nationwide seismic activity forecast map showing the probability, in colored stages, of a region being struck by a strong tremor within a certain period.