Prime Minister Fumio Kishida called off a planned trip to Central Asia out of an abundance of caution following the warning. Bullet trains were running at reduced speeds, national broadcaster NHK is running cautionary graphics and some semiconductor-related factories temporarily halted production. Some beaches in the affected regions have been closed off for the time being, as per local reports.
A megaquake in what’s known as the Nankai trough could surpass the damage from the March 2011 earthquake and tsunami that devastated the northern coast of the main island of Honshu. The zone, where the Philippine sea plate subducts underneath the Eurasian continental plate, sees a major tremor occurring in 100- to 150-year cycles.
Precautionary system
The precautionary warning system for an increased risk of a quake, implemented in 2019, kicks in when a magnitude-6.8 or larger earthquake strikes an area where megathrusts are expected to occur, or when anomalous shifts in the plates are detected. Depending on the size of the earthquake at the time, the authorities can issue different levels of caution, and in some cases warn people to evacuate away from tsunami-prone areas for as long as a week.
“This is advice to be prepared for the possibility that major earthquakes will continue,” Kishida told reporters in Nagasaki, where he was attending ceremonies for the 79th anniversary of its atomic bombing. “It’s not a warning to evacuate in advance, nor is it a notice that an earthquake will occur within a certain period, but it is the first time, so I think the people will be extremely uneasy.” Hours after he spoke, a 5.3 magnitude quake hit Kanagawa, shaking buildings in neighboring Tokyo. There was no threat of a tsunami, NHK said.
