Japan escapes worst of magnitude 7.7 quake but experts warn of potential bigger one

Northeast Japan escaped relatively unscathed from the magnitude 7.7 earthquake that struck off its coast on Monday, but residents have been advised to stay alert as it is too early to tell whether the tremor was the main shock or a precursor to a far larger one.Hours after the quake, the Japan Meteorological Agency (JMA) issued a special advisory warning of a slightly elevated risk of a temblor with a magnitude of 8 or stronger in the coming days.There was a 1 per cent chance of a megaquake, compared to 0.1 per cent at other times, it said, particularly close to the Chishima Trench, about 150km (93 miles) off the coast of Hokkaido, and the Japan Trench, which is further south and around 300km offshore.However, the warning was only of increased risk, rather than a specific prediction, it said.01:20Over 170,000 evacuated as earthquake shakes Japan