A colossal hydropower project under construction on the Yarlung Tsangpo River in Tibet, known as the Brahmaputra downstream, is built directly on an active geological fault line, according to a recent report by Chinese government-backed geologists. The findings highlight significant risks to the structural integrity of the dam and its related infrastructure.
Geological Vulnerability Revealed
The study, published in the Chinese-language journal Sedimentary Geology and Tethyan Geology, identifies the Paizhen Fault as traversing the site of the ambitious hydropower initiative. Researchers from Chengdu University of Technology and the China Geological Survey concluded that this fault, highly active since the Pleistocene epoch, could severely compromise the stability of the dam, roads, bridges, and tunnels in the area. They noted that the fault has fractured surrounding rock formations, reducing their mechanical strength and making engineering structures more susceptible to damage.
Furthermore, the terrain within the reservoir area is described as having a "loose structure and weak cohesion." The report warns that prolonged immersion combined with fault activity and seismic events could easily trigger widespread slope instability on both sides of the reservoir.
High Seismic Risk in the Himalayas
The Paizhen region, including the Pai village area within the construction zone, is located in one of the most seismically active belts of the Himalayas, where the Indian and Eurasian tectonic plates continue their collision. Geological records indicate that the Paizhen Fault has remained active from the Early Pleistocene through the present Holocene epoch, with evidence of activity as recently as 9,500 years ago.
The researchers cited the magnitude 6.9 earthquake that struck Milin, Tibet, in 2017, at the northern end of the fault line, as clear evidence of the area's ongoing seismic potential. They stressed that such regional seismic action could easily induce landslides and collapses, posing a direct threat to both facilities and personnel. Consequently, the study recommends strengthening structural stability safeguards during construction, including slope reinforcement and retaining barriers, to mitigate the risk of landslides and collapses.
Downstream Concerns and Geopolitical Implications
Construction on the dam, slated to be the world's largest hydropower project, commenced last year. It is designed to generate approximately 300 billion kilowatt-hours of electricity annually, tripling the capacity of China's Three Gorges Dam. The Yarlung Tsangpo transforms into the Brahmaputra River upon entering India's Arunachal Pradesh, flows through Assam, and then becomes the Jamuna River in Bangladesh.
For India, the implications extend beyond engineering challenges. The Brahmaputra is a critical river system, supporting vast agricultural lands, providing drinking water, sustaining fisheries, and enabling hydropower generation, impacting livelihoods across India's Northeast. India has consistently voiced concerns regarding China's upstream activities on the river, citing potential risks to water security, ecological balance, and the well-being of downstream communities.