A powerful earthquake has struck New Zealand's South Island.<br/><br/>The US Geological Survey said the magnitude-7.4 quake hit some 95 kilometre from Christchurch. <br/><br/>Christchurch is still recovering from the 2011 earthquake that killed 185 people and destroyed the city centre.<br/><br/>New Zealand lies on the notorious Ring of Fire, the line of frequent quakes and volcanic eruptions that circles virtually the entire Pacific rim.