If a large earthquake occurs along the Nankai Trough, the government is considering evacuating residents in surrounding areas as well, as there is a high chance of other large quakes and aftershocks following along the fault, the Cabinet Office revealed on July 3.
A working group at the Cabinet Office's Central Disaster Management Council, which is tasked with considering countermeasures for large earthquakes along the Nankai Trough, is considering including widespread evacuations after listening to the testimony of experts, and will release a full written summary of their plans this fiscal year.
The working group highlighted the high chance of large scale earthquakes occurring in other regions in the designated earthquake focal area along the Nankai Trough, which spans offshore areas from the Tokai region all the way to Kyushu, if a tremor of at least magnitude 8 occurs along half of the focal area. Thus, the Cabinet Office suggested a plan ordering all residents living along the coast in those areas to evacuate for a period of several days due to the risk of tsunami from secondary quakes wiping out coastal communities.
Even in the event of a quake registering around magnitude 7 in the focal area, there is still a comparatively high possibility that an even larger tremor will follow, so the government is also pushing for the early evacuation of the elderly and those with disabilities in this case as well.
Additionally, the working group suggested it may also include in the report the need to reconsider current disaster measures, as they assume that earthquakes can be predicted ahead of time.
Currently, the Act on Special Measures Concerning Countermeasures for Large-Scale Earthquakes, which was drawn up specifically for Tokai earthquakes, assumes that a quake can be predicted two to three days ahead of time, leaving enough time for measures such as halting transportation services. However, it was judged that current scientific techniques cannot make predictions with such high accuracy, and thus it is necessary to revise the countermeasures.