The landslides on the north bank of the Yangtze River in the reservoir area of the Three Gorges Dam that started last week have not threatened the safety of residents or local shipping, authorities said in Beijing on Wednesday.
The two landslides were "quite small" and no one lives in that area, Jia Jialin, deputy director of the Three Gorges geological disaster prevention team under the Ministry of Land and Resources, said.
No one was injured and there were no economic losses as a result of the landslides, he said.
About 70,000 cu m of rock and earth fell into the Yangtze in the Wuxia area of the Three Gorges reservoir in Chongqing municipality.
About 30,000 cu m of rock in the area are still unstable and prone to collapse, staff at the Wuxia geological monitoring station said.
However, the situation is "under control", Jia said.
The Yangtze River maritime safety administration and the local government are keeping a close watch on the unstable areas, and ships have been alerted to the situation, he said.
Landslides are common in the area along the river, Li Lieru, director of the disaster prevention team, said.
But there is no danger of the world's largest hydraulic dam triggering landslides, he said.
"Moreover, there is a wide range of factors involved in the occurrence of landslides," he said.
"Geographical conditions, rainfall and human activity all play a part."
There have been fewer rockfalls and landslides in the reservoir area than were predicted at the launch of the dam project, and those that have happened have been less intense than forecast, Li said.
The better-than-expected situation is due to the government spending more than 10 billion yuan ($1.45 billion) since 2001 on precautionary measures, he said.
These include "close monitoring and management of the zones at risk", and in a number of cases, the relocation of residents to ensure their safety, Li said.
More than 3,000 monitoring stations are operating in areas prone to landslides and at other sites where there are potential threats, he said.
The government has also set up specialist teams and mobilized residents to detect possible geological disasters, to avoid or minimize losses as the water level keeps rising, Jia said.