WELLINGTON, NEW ZEALAND -- The U.S. Geological Survey says a powerful 7.0 magnitude earthquake shook the Pacific archipelago of Vanuatu on Sunday, and a tsunami warning has been issued for possible hazardous waves in nearby waters.

The quake was centred 23 kilometres (15 miles) from Port Olry and hit at a depth of 27 kilometres (17 miles), the agency said.

The Pacific Tsunami Warning Center issued a tsunami warning for coasts located within 300 kilometres (186 miles) of the epicenter. There were no immediate reports of damage or casualties.

Vanuatu is home to about 280,000 people and is prone to natural disasters, with a half-dozen active volcanoes as well as regular cyclones and earthquakes. It sits on the Pacific "Ring of Fire," the arc of seismic faults around the Pacific Ocean where earthquakes and volcanoes are common.