Japan was on high alert today after a tsunami [3] hit Miyagi Prefecture, just 20 months after the one [4] that devastated the country last year. English-language publication Japan Times [5] declared that five people had been taken to hospital after the one-meter wave reached dry land. The quake, which registered 7.3 on the Richter scale, occurred some 150 miles southeast of Kamaishi, and was registering 5 by the time it hit the coast. With the memory of March 2011 still fresh in the Japanese people's minds, news outlets urged residents to flee to higher ground as soon as the warning sounded. Not long ago, however, officials said [6] there was no threat of a larger tsunami.

Although buildings shook dramatically and some train services were suspended, the alert was lifted just after 7:15 p.m. local time. Workers at the Fukushima [7] Nuclear Power Station were not evacuated, although they were taken to safe areas within the plant.

The quake appeared [8] on Google Public Alerts just over four hours ago. But, according [9] to Sam Byford, a writer for The Verge who lives in Tokyo, he received warning [10] of an imminent earthquake, "risk dangerous level" via a friend on Twitter, a full 12 hours earlier. "Two hours later and my phones are blaring with alerts and I'm taking shelter under my door frame. All the while I'm wondering how on earth Twitter has given me the ability to predict the future," he wrote.