Alert triggered panic in archipelago of 125 million people with many cancelling holidays, stocking up on essentials.
Japan has lifted it warning for a higher than usual risk of a major earthquake one week after a strong tremor on the edge of the Nankai Trough seabed zone caused the government to issue its first “megaquake” advisory.
Citizens can now return to normal life after no abnormalities were observed in seismic activity in the past week at the Nankai Trough, located along Japan’s Pacific coast, Yoshifumi Matsumura, the state minister for disaster management, said on Thursday.
On August 8, the Japan Meteorological Agency released an advisory that there was a “relatively higher chance” of a Nankai Trough “megaquake” as powerful as magnitude 9 after a magnitude 7.1 quake hit the country’s southwest.
While the advisory was not a definitive prediction, the government asked residents of western and central regions to review evacuation procedures in case of a severe earthquake and tsunami.
Prime Minister Fumio Kishida cancelled a visit to Central Asia and Mongolia over the weekend to prioritise disaster management.
The alert that such a catastrophe might hit the archipelago of 125 million people prompted thousands of Japanese to cancel holidays and stock up on essentials, emptying shelves in some stores.
Matsumura cautioned that lifting the warning didn’t mean the risk of a major earthquake has been eliminated.
Last week’s magnitude 7.1 earthquake struck Kyushu, injuring 15 people and triggering a tsunami warning.
The government has previously said the next “megaquake” has a roughly 70 percent probability of striking within the next 30 years.
The Nankai Trough is an 800km (500-mile) undersea trench between two tectonic plates in the Pacific Ocean. It runs parallel to Japan’s Pacific coast, including the Tokyo region, home to about 40 million people.
Sitting on top of four major tectonic plates, Japan is one of the world’s most earthquake-prone countries, seeing about 1,500 quakes every year, most of them minor.
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 one each in 1944 and 1946.
More than 15,000 people were killed in a magnitude 9 quake in 2011 and the tsunami it triggered. The waves also caused triple reactor meltdowns at a nuclear power plant in northeast Japan.
