The earthquake on Wednesday triggered evacuations across the South Pacific as island nations issued tsunami alerts.
The quake struck 340km east of Kira Kira in the Solomons, the Pacific Tsunami Warning Center in Hawaii said as it issued warnings for the Solomons and other South Pacific nations including Australia and New Zealand. It later cancelled the warnings for the outlying regions.
A tsunami measuring 0.9 metres hit near the town of Lata on the remote Santa Cruz Island, swamping some villages and the town's main airport as people fled to safety on higher ground.
More than three dozen aftershocks up to magnitude 6.6 rocked the region in the hours after the quake, the US Geological Survey said.
Lata Hospital's director of nursing, Augustine Pilve, told New Zealand television that five people had been killed, including a boy about 10 years old, adding that more casualties were possible as officials made their way to at least three villages that may have been hit.
"It's more likely that other villages along the coast of Santa Cruz may be affected," he said.
Deaths and damages
Disaster officials in the Solomon Islands capital Honiara told the Solomon Islands Broadcasting Corporation that they believed six people were dead and that five villages had suffered damage.
Solomon Islands Police Commissioner John Lansley said it was too early to fully assess the damage or casualty numbers, and said authorities hoped to send aircraft to the region on Thursday to help determine the extent of the damage.
Luke Taula, a fisheries officer in Lata, said he watched the tsunami as it came in small tidal surges rather than as one large wave.
"We have small waves come in, then go out again, then come back in. The waves have reached the airport terminal," he said.
The worst damage was to villages on the western side of a point that protects the main township, he said.
"There are reports that some communities have been badly hit, their houses have been damaged by the waves."
About 5 000 people lived in and around the town, but the area was deserted as people fled to higher ground, Taula said.
The Solomon Islands, perched on the geologically active "Pacific Ring of Fire", were hit by a devastating tsunami following an 8.1 magnitude quake in 2007. At least 50 people were killed then and dozens left missing and more than 13 villages destroyed.
"It's an area that is very prone to earthquakes," said Jonathan Bathgate, seismologist at Geoscience Australia. "We've had seven 6-plus magnitude earthquakes in this region since January 31, so it has been very active in the past week."
Initial signs were that the tremor was a thrust quake, in which vertical movement in the continental plates generates higher risk of tsunami, Bathgate added.
Authorities in the Solomons, Fiji, Guam and elsewhere had urged residents to higher ground before the Pacific Tsunami Warning Center cancelled its alerts.
"The earthquake would have to be quite a bit bigger to make a much more sizeable tsunami," said Brian Shiro, geophysicist for the centre in Hawaii. – Reuters