TOKYO - Japan's weather agency canceled a mistakenly issued warning of strong seismic shaking from an earthquake off northern Japan on Friday after overestimating the temblor's magnitude as a catastrophic 9.9, causing temporary public transport disruptions in parts of the country.
The Japan Meteorological Agency said its computer system erroneously determined the quake's focus, resulting in the magnitude being overestimated. It issued the warning for a wide area extending from northern to central Japan at 12:40 p.m., saying that the earthquake had occurred in the Chishima Islands, also known as the Kuril Islands, off Hokkaido.
It later confirmed that a M6.9 quake occurred near Russia's Kamchatka Peninsula at a depth of 160 kilometers at around 12:38 p.m.
The early warning urged the public to brace for a seismic shock at the maximum 7 level of the Japanese intensity scale, but the strongest shaking recorded was just 1 in Hakodate in southwestern Hokkaido, the agency said.
Following the warning, 14 tram trains in Sapporo, Hokkaido, halted for several minutes until it was deemed safe to resume service, according to their operator.
Bullet train services on the Tokaido Shinkansen Line were also temporarily suspended between Shin-Yokohama and Toyohashi stations. However, the operator JR Central said Friday night that the quake warning was not the direct cause of the suspension.
The early quake warning was canceled eight minutes after it was issued. Many members of the public received the alert on their smartphones or learned of it through TV and radio broadcasts or municipal public address systems.
Had a M9.9 temblor occurred, it would have released about 22 times as much energy as the M9.0 quake that struck off northeastern Japan on March 11, 2011. The megaquake set off massive tsunami along Japan's coast and resulted in a severe nuclear disaster.
Chief Cabinet Secretary Minoru Kihara told a news conference later Friday that the government is taking the matter seriously.
"We caused a great deal of worry and placed a burden upon those who took shelter or took action to ensure their safety, as well as on others such as transport systems and businesses that were affected," he said.
Hokkaido, the country's northernmost main island, and surrounding areas are among the regions where the agency has urged the public to prepare for a potential megaquake along the Japan Trench and Chishima Trench off northern Japan.
