<p>A magnitude 6.1 earthquake struck off Hokkaido in northern Japan on Saturday night, the US Geological Survey and the Japan Meteorological Agency said.</p>.<p>No tsunami warning was issued after the offshore quake, which shook the coastal cities of Kushiro and Nemuro.</p>.<p>Major Japanese media outlets carried no immediate reports of damage or injuries.</p>.<p>The quake hit at 10:27 pm (1327 GMT) at a depth of around 43 kilometres (27 miles), the USGS said.</p>.<p>An expert speaking on public broadcaster NHK warned residents to be vigilant against quakes for about a week.</p>.<p>Earthquakes are common in Japan, which sits on the Pacific "Ring of Fire", an arc of intense seismic activity that stretches through Southeast Asia and across the Pacific basin.</p>.<p>The country has strict construction regulations intended to ensure buildings can withstand strong earthquakes, and routinely holds emergency drills to prepare for a major jolt.</p>
<p>A magnitude 6.1 earthquake struck off Hokkaido in northern Japan on Saturday night, the US Geological Survey and the Japan Meteorological Agency said.</p>.<p>No tsunami warning was issued after the offshore quake, which shook the coastal cities of Kushiro and Nemuro.</p>.<p>Major Japanese media outlets carried no immediate reports of damage or injuries.</p>.<p>The quake hit at 10:27 pm (1327 GMT) at a depth of around 43 kilometres (27 miles), the USGS said.</p>.<p>An expert speaking on public broadcaster NHK warned residents to be vigilant against quakes for about a week.</p>.<p>Earthquakes are common in Japan, which sits on the Pacific "Ring of Fire", an arc of intense seismic activity that stretches through Southeast Asia and across the Pacific basin.</p>.<p>The country has strict construction regulations intended to ensure buildings can withstand strong earthquakes, and routinely holds emergency drills to prepare for a major jolt.</p>