A powerful earthquake struck central Japan, killing at least one person, destroying buildings, knocking out power to tens of thousands of homes and prompting residents in some coastal areas to flee to higher ground. The quake with a preliminary magnitude of 7.6 triggered waves of about 1 metre along Japan's west coast and neighbouring South Korea, with authorities saying larger waves could follow. The Japan Meteorological Agency (JMA) issued tsunami warnings for the prefectures of Ishikawa, Niigata and Toyama. A major tsunami warning - the first since the March 2011 earthquake and tsunami that struck northeastern Japan - was issued for…