An earthquake measuring 5.0 on the Richter Scale jolted the bordering region of Dujiangyan city and Pengzhou city in southwest China's Sichuan Province Tuesday. The quake struck at 2:11 p.m., and no casualties had been reported as of 3 p.m, Xinhua quoted the provincial seismological bureau as saying in a press release. No damage had been reported to the Dujiangyan irrigation system, the world's oldest irrigation project still functioning, the bureau said. The epicenter of the quake was at 31.1 degrees north latitude and 103.7 degrees east longitude, at a depth of 10 km. The bureau said the tremor was an aftershock of the Wenchuan earthquake that shook southwest China on May 12, 2008.