An earthquake measuring 4.1 on the Richter scale jolted Zigui County in central China's Hubei Province at 4:01 p.m. Saturday, the National Seismic Network reported.

The epicenter is about 30 kilometers from the Three Gorges Dam, a leading water conservancy project on the Yangtze River, China's longest waterway.

"The tremor had not affected the dam itself," said a spokesman with Three Gorges Project Corporation. "The dam was built to endure far stronger earthquakes," he said.

Launched in 1993, construction of the gigantic concrete structure of the Three Gorges Dam was completed and began to hold water in May 2006.

The dam was unaffected in the 8.0-magnitude earthquake that hit Sichuan Province on May 12.

The Zigui quake was felt across the county as well as in Yichang City. No casualties have been reported as of 9:35 p.m. on Saturday. But cracks appeared on the walls of seven houses in the county.

The local government has started monitoring over landslide risks in the project area round-the-clock. Teams of officials have been sent to affected villages to investigate potential damages.

"We assume the epicenter is along the banks of the Xiangxi River, a Yangtze tributary in the dam area," said Zheng Zhiwen, a spokesman with the county committee of the Communist Party of China (CPC).

(Xinhua News Agency November 23, 2008)