USGS said the earthquake was 7.8 strong – enough to cause catastrophic damage and human casualties
At the same time Tsunami waves threatened the New Zealand coats triggering tsunami warnings early Monday morning. A first 2.5 m wave arrived terrifying residents and tourists.
New Zealand civil defense wants everyone in coastal areas to get to safety and higher grounds.
The US Geological Survey said the earthquake hit just after midnight (11:02 GMT on Sunday), approximately 95km (59 miles) from Christchurch.
The tsunami arrived in the north-eastern coast about two hours later. Officials said the first waves may not be the largest, with tsunami activity possible for several hours.
Residents were warned to head inland or for higher ground along the coast.
A gauge at Kaikoura, 181 km (112 miles) north of Christchurch, measured a wave of 2.5m.
Smaller waves are said to be arriving in Wellington and other areas. This is according to official monitoring websites. The New Zealand ministry of civil defense expects the highest wave to be 5m and is expected between Malborough, the north-eastern tip of the South Island, and Banks Peninsula, just south of Christchurch.
New Zealanders are used to earthquakes. The country lies on the notorious Ring of Fire, the line of frequent quakes and volcanic eruptions that circles virtually the entire Pacific rim.
At this time only one person is feared to be dead and only minor incidents of injuries are known.
Christchurch is still recovering from the 2011 earthquake that killed 185 people and destroyed the city centre.
