YANJIN, Yunnan, Aug. 27 (Xinhua) -- Residents in Yanjin, southwest China's Yunnan Province, should prepare precautions against potential strong aftershocks, said Hu Yonglong, deputy director of the provincial seismological bureau, on Sunday.

An earthquake measuring 5.1 degrees on the Richter scale jolted Yanjin County, Zhaotong City, at 1:51 p.m on Friday, killing one people and injuring 31 others, including 10 seriously.

The area reported more than ten aftershocks, with the strongest of 3.3 degrees on the Richter scale, according to the local seismological bureau.

One more people was killed and another injured after being hit by the rolling stones from the mountains after a 2.8 magnitude aftershock on Sunday, said the bureau.

Hu urged local officials and residents to have damaged houses repaired and reinforce the mountain slopes besides which the roads and rivers run through.

Aftershocks as low as two to three degrees on the Richter scale can even topple the damaged houses, and this is especially true in the raining season, he added.

Yanjin County is located on the Yunnan-Guizhou Plateau and has a population of 350,000.

A 5.1 magnitude earthquake hit Yanjin and neighboring Daguan county on July 22, killing 22 and injuring 106 people.

Yanjin is located on an earthquake belt where at least nine major quakes have been recorded, the strongest of which was measured at 7.1. Enditem