The quake hit at 00:38 am (2208 IST today) and was centred 98 kilometres east of the city of Hualian at a depth of 38 kilometres, USGS said.
It estimated there was a low likelihood of casualties and damage from the tremor, which struck 63 kilometres southwest of the Japanese town of Yonakuni in the Yaeyama Islands.
A strong 6.3-magnitude quake which hit central Taiwan on Sunday killed four people and caused widespread landslides.
The island lies near the junction of two tectonic plates and is regularly hit by earthquakes.