A tsunami warning has been issued after two large earthquakes struck off the coast of Vanuatu. A tsunami warning was issued after two powerful earthquakes struck off the coast of Vanuatu on Saturday, with hazardous waves possible along coastlines within 300 km of the epicentre. A 6.9-magnitude earthquake struck off Vanuatu on Saturday, triggering a tsunami warning that was later lifted. A second quake and several aftershocks.