The quake hit at 2:48 p.m. PT, 18 miles south of Naalehu at a depth of about 10 miles. Naalehu is at the southern tip of the Big Island.
It was unclear if there was any significant damage to buildings or injuries.
The Hawaii Emergency Management Agency said there was no threat of a tsunami.
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There were several apparent aftershocks recorded, one measuring 4.1 and another at 2.8, according to the USGS.