A magnitude 5.5 earthquake, which measured a 4 on the shindo (intensity) scale, was detected at a depth of 50 kilometers in northeastern Chiba Prefecture on Monday at 10:07 p.m.
No tsunami warning was issued.
The quake triggered the government's early warning earthquake alert on smartphones in the Kanto area, with many taking to social media to say that the alert had left them more shaken than the temblor itself.
"I swear, that earthquake alert sound is worse by itself than any earthquake we've had since they created that system. An ugly, frightening sound. Though I suppose that's the goal," wrote Twitter user @rdviii.
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