An earthquake with a preliminary magnitude of 5.0 struck the northern part of Nagano prefecture in central Japan on Saturday, the country’s weather agency said.The 1.20pm quake in Omachi registered an upper 5 on the Japanese seismic intensity scale of 7, strong enough to make movement difficult without support.It occurred at a depth of 10km (six miles), according to the Japan Meteorological Agency.It was not immediately clear whether there was any damage.Earthquakes are common in Japan,...