Beijing: A study by Chinese geologists has found that an active fault line beneath the world’s largest hydropower project on the Brahmaputra River in Tibet could affect its structural stability, raising questions over Beijing’s repeated claims that it would help prevent disasters in the region.
The project is close to the Indian border in Arunachal Pradesh.
The scientists said a fracture in the Earth’s crust in the eastern Himalayan region could significantly affect the structural integrity of the massive hydropower project’s infrastructure, the Hong Kong-based South China Morning Post reported Thursday.
In a paper published last month in the Chinese-language journal Sedimentary Geology and Tethyan Geology, the researchers said the Paizhen Fault, which has been highly active since the Pleistocene, or Ice Age, will have a major impact on the structural stability and construction of nearby structures, including dams, roads, bridges and tunnels, as well as the reservoir area.
The study was supervised by the state-owned China Geological Survey.
According to the researchers, prolonged fault activity has fractured and weakened the surrounding rock formations, making the foundations and structural stability of nearby engineering projects more vulnerable to damage.
The Paizhen area is located within the reservoir area of the Yarlung Tsangpo downstream hydropower station, the paper said.
China refers to the Brahmaputra as the Yarlung Tsangpo.
China formally began construction of the USD 167.8-billion dam on the Brahmaputra in Tibet last July.
Expected to generate more than 300 billion kWh of electricity annually, the dam is projected to meet the annual power needs of more than 300 million people.
The dam is being built in a massive gorge in the Himalayas where the Brahmaputra makes a sharp U-turn before flowing into Arunachal Pradesh and later Bangladesh.
China went ahead with the project despite enormous engineering challenges as the site lies along a tectonic plate boundary that experiences frequent earthquakes.
The Tibetan Plateau, often described as the roof of the world, is prone to periodic earthquakes because of the movement of tectonic plates beneath it.
The researchers cited the magnitude 6.9 earthquake that struck Milin in Tibet in 2017 near the northern end of the fault as evidence that the fault remains seismically active.
Under regional seismic action, landslides and collapses can easily be induced, threatening the safety of engineering facilities and personnel, they said.
The recent findings add to concerns over the project’s structural safety, with the researchers urging engineers to reinforce vulnerable slopes and install retaining structures to reduce the risk of landslides and collapses.
However, China has consistently sought to allay concerns over the safety of the project. Beijing has repeatedly claimed that the project meets the highest industry standards and would help prevent disasters in the region.
An official statement issued in December 2024 said the hydropower project was safe and prioritised ecological protection.
Through extensive geological explorations and technical advancements, a solid foundation has been laid for the science-based, secure, and high-quality development of the project, it said.
In July last year, a Chinese Foreign Ministry spokesperson said China was highly responsible in developing cross-border rivers and had rich experience in building hydropower projects.
In planning, designing and constructing the hydropower project in the lower reaches of the river, China strictly followed the highest industry standards while protecting the ecological environment in an all-round way, the spokesperson had said.
He also maintained that the project would help prevent disasters along the river and would not have a negative impact on downstream regions.
The Brahmaputra flows across the Tibetan Plateau, carving out the world’s deepest canyon before entering India.
The study was conducted by geologists from the Chengdu University of Technology, the Civil-Military Integration Centre of the China Geological Survey, and the Middle Yarlung Zangbo River Natural Resources Observation and Research Station, according to the South China Morning Post.
The researchers said Pai (also called Paizhen) village in Tibet, where construction is underway, lies in the Himalayan seismic belt, one of the most earthquake-prone regions in China and neighbouring regions, where intense seismic activity has developed along the Yarlung Tsangpo.
Its records of Quaternary tectonic activity provide an important basis for exploring the structural stability of nearby projects, the paper said.
The Paizhen Fault is part of a network of tectonic faults in the eastern Himalayan region created by the collision of the Indian and Eurasian tectonic plates. The researchers said the fault has remained active since the Early Pleistocene and continues to exhibit strong activity during the present Holocene epoch. Dating of ancient lake sediments suggests the fault remained active as recently as 9,500 years ago.
