TOKYO (AP) " An erroneous alert Monday that a massive earthquake had hit the Tokyo area sent many in Japan into a brief panic and disrupted some train services.
The Japanese Meteorological Agency sent the alert just after 5 p.m., saying a magnitude-9.1 quake had struck.
Some people who have smartphone apps that alert them to quakes got warnings popping up on their screens. The agency's alert, which was canceled within seconds, set off alarmed chatter on Twitter.
The meteorological agency said it was investigating why the alert got sent. An agency official, who spoke on customary condition of anonymity, said the reason may have been lightning hitting a seismograph, an instrument that monitors quakes.
Following the alert, some Tokyo train services shut down temporarily.
Japan is among the most quake-prone nations in the world. A magnitude-9 quake off the country's northeast coast in March 2011 set off a giant tsunami that killed more than 18,000 people and sent three nuclear reactors into meltdowns.
This story has been automatically published from the Associated Press wire which uses US spellings