The quake struck 98 kilometres (60 miles) southeast of the capital Honiara in the early hours of today at a depth of approximately 23 kilometres, USGS said.
The Solomons are part of the Pacific "Ring of Fire", a zone of tectonic activity known for its frequent earthquakes and volcanic eruptions.
In 2013, the Solomons were hit by a tsunami after an 8.0-magnitude quake, leaving at least 10 people dead and thousands homeless after buildings were destroyed.