SYDNEY (AFP) - A 6.9-magnitude earthquake hit off the Vanuatu coast on Thursday (April 7), the second major tremor in the area in as many days, but there was no tsunami threat or reports of damage, seismologists said.

The quake struck at a depth of 32km some 109km west of Sola on Vanua Lava island and 453km from the capital Port Vila at 3.32am GMT, the United States Geological Survey said.

It was the third quake to hit the region in a week, after similarly sized ones on Sunday and Wednesday.

"The last two did not cause any damage so we don't expect this one to," Geoscience Australia seismologist Spiro Spiliopoulos told AFP.

"This earthquake is a little bit further north than the last two, there's a sequence of earthquakes happening and they seem to be moving gradually north.

"Often you get a large main shock and then lots of aftershocks. In this case you are getting three major shocks. We've seen it before but it's not the most common occurrence."

Vanuatu is part of the "Ring of Fire", a zone of tectonic activity around the Pacific that is subject to frequent earthquakes and volcanic eruptions.