Tuesday's tremor hit just hours after the Olympic torch completed a tour of the disaster zone from May earthquake, state media said.
The recent tremor was also felt in Xining city, the capital of Qinghai province, a tourist was quoted by the AFP news agency as saying.
Another tourist was quoted as saying the tremor had been felt as far away as Xian city in north China's Shaanxi province.
The May 12 earthquake in Sichuan killed 69,197 people and left 18,209 others missing, according to the most recent data from the government.
The 8.0-magnitude earthquake sparked international help from rescue teams and an enormous domestic relief effort, ahead of the Beijing Olympics.