Sydney - A strong earthquake with a preliminary magnitude of 7.7 Thursday has struck off the Solomon Islands, prompting a tsunami alert for the region.

The earthquake, which struck at 17:38 UTC on Thursday, was centered about 68 kilometers (42 miles) southwest of Kirakira in the Solomon Islands, or 211 kilometers (127 miles) southeast of Honiara. It struck at a shallow depth of just 48 kilometers.

The US Geological Survey (USGS) puts the preliminary magnitude of the earthquake at 7.7, down from an initial estimate of 8.0. The Pacific Tsunami Warning Center has issued a tsunami alert for the Solomon Islands, Vanuatu, Papua New Guinea, Nauru, New Caledonia and Tuvalu and Kosrae.

The Pacific Tsunami Warning Center said in a bulletin, "Based on all available data a tsunami may have been generated by this earthquake that could be destructive on coastal areas even far from the epicenter."