The quake struck the Qinghai province at a depth of 6.2 miles on Monday morning, the agency said. The USGS said the quake's epicenter was located 1,120 miles west of Beijing.
China's Earthquake Administration confirmed the earthquake, but said it had a magnitude of 6.3 on its scale.
The USGS said the quake's epicenter was 35 miles east of Da Qaidam district, in northern Qinghai. The population of the county seat, Da Qaidam town, is about 15,000 people.
An official at the Da Qaidam administrative committee said authorities have sent 180 people to investigate but there were no immediate reports of casualties.
The quake was felt in Golmud, the second-largest city in the province with a population of 270,000, 100 miles south of the epicenter.
Hotels in the city said they could feel the tremors but that the quake was not major enough to cause significant damage.
China's far west is fairly earthquake-prone. A 7.9 magnitude earthquake on May 12 devastated parts of Sichuan province, just east of Tibet, killing 70,000 people and leaving 5 million homeless.