Authorities say tsunami waves have been observed after a magnitude-7.4 earthquake struck Vanuatu. The quake struck 37km from the capital, Port Vila at 12:53pm AEDT. It struck at a depth of 10km, the United States Geological Survey said. The Pacific Tsunami Warning Center said tsunami waves had been observed, and predicted waves of up to 1 metre along some parts of Vanuatu's coastline. Tsunami waves of less than 30 centimetres above the tidal level were predicted for Pacific island nations including Fiji, Kiribati, New Caledonia, Solomon Islands and Tuvalu. The Bureau of Meteorology said there was no tsunami threat to Australia. Authorities are monitoring for any sign of a tsunami. Dan McGarry, a local journalist in Port Vila, said it was a "violent, high-frequency shake" that lasted for about 30 seconds. He said there were sirens being heard around the capital. Witnesses have reported major landslides near the capital.