THE 5.6 MAGNITUDE EARTHQUAKE that shook the city of Shaotong in northwestern Yunnan Province, China, on 10 August 2004 reportedly cracked 22 earth fill dams, endangering 47,000 people living in downstream areas.
In a report released by the Ministry of Water Resources, it was said that among 22 reservoirs encountering breaching, 21 were of small scale with a dam height from 10-20m. Four of these stored more than 1Mm3. One of the dams affected was the 13.5m high Yongfeng reservoir, which stores over 3.87Mm3 of water. Two cracks were found in the upper part of the reservoir wall. However, no flooding had occurred.The tremor was the third earthquake to hit the area within a year. Earthquakes measuring 5.1 and 5.0 occurred on 15 November and 26 November 2003 respectively. Four people were killed and 120 injured in those tremors.