A 30-centimeter (12-inch) tsunami hit Japan on Friday after a 7.1-magnitude earthquake was felt in the country, AFP reported, citing local broadcaster NHK.

There were no immediate signs of serious damage or injury from the tsunami and people were being warned to stay away from the coast. The tsunami hit around an hour after the strong quake.

Workers at the crippled Fukushima nuclear plant were “ordered to evacuate from the waterfront”, news agency Kyodo reported, though no new abnormalities had been found at the power station.

The earthquake struck at a depth of 10 kilometers (6.2 miles) at 2:10 a.m. (Saturday) local time, 327 kilometers southeast of Ishinomaki in Miyagi Prefecture, according to the U.S. Geological Survey.

The USGS initially said its magnitude was 7.5, and issued a green alert on its website, signaling a low probability of deaths or economic losses.

In the town of Ofunato, a 20-centimeter tsunami was logged just after 3:00 a.m. local time. The waves were expected to hit several places along the northeast coast that was devastated by the huge tsunami of 2011.

Eastern Japan, a seismically active region, was struck by a 6.5 magnitude earthquake last month causing tremors that were felt 600 kilometers away in Tokyo.

More than 18,000 people died when a 9.0 magnitude sub-sea earthquake sent a towering tsunami barrelling into Japan’s northeast coast in March of 2011.

Cooling systems at the Fukushima nuclear plant were knocked out, sending reactors into meltdown and forcing tens of thousands of people to flee.