The minister of disaster management stated that if there is no further significant seismic activity, Japan will suspend its “megaquake” warning that has been in effect for a week.
Thousands of Japanese cancelled holidays and stocked up on necessities in response to the alarm last week, leaving some businesses with empty shelves.
“If no particular change in seismic activity or crustal deformation is observed, at 17:00 (0800 GMT) today, the government will end the special call for attention,” said Yoshifumi Matsumura, minister of state for disaster management.
“The possibility of a major earthquake has not been eliminated,” he said, urging citizens to regularly check their preparedness “for the major earthquake that is expected”.
The probability of such an incident was “higher than normal” on Thursday, according to Japan’s weather agency, following a magnitude 7.1 jolt earlier in the day that left 14 injured.
That was a subduction megathrust earthquake, a type of tremor that has historically happened in pairs and has the potential to cause enormous tsunamis.
The warning pertained to the Pacific Ocean’s Nankai Trough, a “subduction zone” situated between two tectonic plates, which has previously experienced significant earthquakes.
The largest urban area in the world, Tokyo region, is situated along the Pacific coast, and the 800-kilometer (500-mile) undersea trough extends from Shizuoka to the southernmost point of Kyushu island.
In 1707, all segments of the Nankai Trough ruptured at once, unleashing an earthquake that remains the nation’s second-most powerful on record.
That quake — which also triggered the last eruption of Mount Fuji — was followed by two powerful Nankai megathrusts in 1854, and then a pair in 1944 and 1946.
Japan’s government has previously said the next magnitude 8-9 megaquake along the Nankai Trough has a roughly 70 percent probability of striking within the next 30 years.
Experts predict that in the worst-case scenario, 300,000 lives might be lost. Some engineers even estimate that the damage, including destroyed infrastructure, could approach $13 trillion.
First under new regulations, the Japan Meteorological Association (JMA) issued its warning following the 2011 earthquake, tsunami, and nuclear accident that claimed around 18,500 lives.
At the Fukushima nuclear facility, the 2011 tsunami caused three reactors to melt down, leading to the greatest nuclear accident in history and the deadliest disaster in Japan since Chernobyl.