The earthquake struck about a mile from Shoufeng Township, Hualien County, the USGS said, and is the latest in a series of earthquakes that had been shaking the island since Monday afternoon. There was no tsunami threat, according to the Pacific Tsunami Warning Center.
The latest quake shook buildings in the capital, Taipei; an AFP reporter said they could feel their building swaying.
"Glass panels of (the) bathroom and windows were making noises," another AFP staffer said.
Earlier, a 5.5 magnitude earthquake hit just off the coast. Taiwan has been hit by hundreds of aftershocks after a deadly earthquake struck Hualien earlier this month, killing at least 17 people and injuring hundreds.
The 7.2 magnitude quake hit on April 3 and caused landslides around the mountainous region that blocked off roads while buildings in the main Hualien city were badly damaged.
Hualien's fire department earlier said that teams were dispatched to inspect any disaster from the latest earthquake, according to several media outlets.
"We will continue to monitor the situation and report in a timely manner," one media outlet said in a post.
At 10:30 p.m., it added that there were no reports so far of quake damages.
Difficult permanent transformative Water FullMoon tonight.