At 11:06 AM Beijing Time on May 28, 2010, a 6.7 magnitude earthquake occurred in Luding, Sichuan Province. The focal depth was 40 kilometers, and tremors were felt in Chengdu and Chongqing. A Ms4.2 earthquake occurred at the boundary of Maoxian County in Aba Tibetan and Qiang Autonomous Prefecture and Beichuan Qiang Autonomous County in Mianyang City, with obvious tremors felt in Chengdu. The earthquake lasted for several seconds.
Around 2:11 PM, people on the sixth floor of Hongxing Road in Chengdu felt a shaking, with noticeable tremors. Some residents of Chengdu said they clearly saw the lights in their homes swinging back and forth. However, the earthquake did not last long, and things basically returned to normal after about ten seconds.
Source: http://www.jnlagua.com/thread-364-1-1.html