Chinese researchers solve mystery of seismic activities at eastern Himalayas

BEIJING -- Chinese scientists have uncovered the key mechanism behind seismic activities in the eastern Himalayas, providing new insights into both the seismic risks and the uplift process of this archetypal mountain belt on Earth, according to a research article recently published in the journal National Science Review.

The Himalayas were formed by the collision of the Indian and Eurasian tectonic plates. While scientists have a relatively clear understanding of earthquake generation along the range's central section, the tectonically more complex eastern sector has remained largely unexplored.

Researchers from the Institute of Tibetan Plateau Research, Chinese Academy of Sciences, utilized new data from their recently deployed broadband seismic array in the eastern Himalayas to analyze the regional stress field and obtain detailed structural information about the converging plates.

The stress field derived from the earthquake focal mechanisms reveals predominant north-south horizontal compression.

From south to north across the eastern Himalayas, the study identified low-angle subduction of the crust-mantle boundary and a flat-ramp geometry in the plate interface within the Indian crust.

The researchers noted that this dominant north-south compression, combined with the gentle underthrusting of the Indian plate, can account for both megathrust earthquake generation and the uplift of the broad mountain ranges beneath the eastern Himalayas.

"In the next phase, we will investigate how continental collision governs both seismic activity and plateau evolution," said Bai Ling, the first and corresponding author of the research article.