At 5:59AM local time Tuesday morning, a magnitude 7.4 earthquake shook the east coast of Japan. The Japan Meteorological Agency issued tsunami warnings and evacuation orders soon after the quake hit, warning of possible 10-foot waves. The quake may have been responsible for an issue at a local nuclear power plant where a pump responsible for cooling fuel rods shut down.
Japanese authorities lifted the tsunami warnings at 9:45AM local time, around four hours after the shaking started. Prefectures along the country’s Pacific coast had been given tsunami advisory indicators, but a stronger tsunami warning was issued to Fukushima prefecture — one of the regions devastated by the magnitude 9.0 quake and subsequent tsunami that caused the disaster at the Fukushima Daiichi nuclear power plant in 2011.
Even small tsunamis can generate dangerous currents
Earthquakes that occur underwater can cause tsunamis by deforming the sea floor faster than water can move out of the way. That massive, sudden displacement generates waves. In this case, it took about half an hour for the waves to reach the shoreline. A three-foot tsunami hit the coast of Soma, 185 miles up the coast from Tokyo, a little more than an hour after the temblor, and another 4.6-foot tsunami washed ashore at Sendai, another 40 miles north, an hour later. This was the largest tsunami in that region since the 30-foot tsunami of 2011, according to the Japan Times.
As of 7:39AM local time, there were 150 people at 5 evacuation centers, the Japan Times says. Five minor injuries have been reported. The cooling equipment for a reactor at the No. 2 power plant at Fukushima, Fukushima Daini stopped working, but resumed functioning at 7:47AM local time, according to the paper. (Fukushima Daini is not the plant that caused a nuclear disaster after being damaged by the 2011 quake and tsunami. That’s Fukushima Daiichi, a nuclear power plant a little more than 6 miles to the north of Daini).