Seismologists today warned Japan to stay vigilant for the next “Big One” after a powerful 7.8-magnitude earthquake hit off the coast of the quake-prone nation, injuring a dozen people. Buildings swayed for around a minute in Tokyo and its vicinity Saturday night as the quake struck at a remote spot in the Pacific Ocean around 874 kilometres (542 miles) south of the capital, the US Geological Survey said. 

Despite its power, there was no risk of a tsunami as its epicentre was a deep 676 kilometres below the Earth’s surface, the USGS and the Pacific Tsunami Warning Center said. 12 people were injured, including a 56-year-old man who broke his ribs, but no one was killed, an official of the Tokyo Fire Department and local media said today. Some 400 people were trapped at the observation decks of Tokyo Tower as its elevators stopped for more than one hour. FULL REPORT