A new study has found evidence that the Indian tectonic plate, long considered a rigid crustal block, is undergoing “subtle” internal deformation. Using high-precision GPS data from stations across India and Sri Lanka, researchers identified distinct crustal movement patterns within the plate, particularly north of the Narmada–Son Lineament in the Central Indian Tectonic Zone (CITZ).

Published in the Royal Astronomical Society’s peer-reviewed journal Geophysical Journal International, the study suggests that long-term tectonic stresses linked to the India–Eurasia collision could influence earthquake potential within the Indian subcontinent.

The study was carried out by a research team led by P.S. Sunil, head, Department of Marine Geology and Geophysics, Cochin University of Science and Technology (CUSAT), along with research scholar M. S. Rose, scientist K. M. Sreejith from Space Applications Centre (SAC-ISRO), and S. Sunda from Airports Authority of India (AAI).

“The collision between the Indian and Eurasian plates, which led to the formation of the Himalayan mountain range, began nearly 50 to 55 million years ago. Since then, several studies have shown that the Indian tectonic plate continues to move northeast at a rate of nearly 50 millimetres per year. The new research challenges the long-standing scientific view that the Indian Plate behaves as a perfectly rigid tectonic block. It presents geodetic and geophysical evidence indicating measurable intraplate deformation within the Indian Plate,” said Mr. Sunil.

Under this SAC-ISRO funded investigation, the researchers used high-precision data obtained from 34 Continuous Global Positioning System (cGPS) stations, including 17 in the GPS-Aided GEO Augmented Navigation (GAGAN) network, implemented jointly by ISRO and AAI located at airports and other sites across India. The dataset included observations collected continuously over a minimum period of three years.

As part of the study, the team derived an updated Euler Pole for the Indian Plate and analysed crustal movement patterns across different parts of the Indian subcontinent. The study found that regions north of the Narmada–Son Lineament exhibit movement patterns distinct from those in the comparatively stable southern region. “This finding further strengthens the argument that the Indian Plate is not a completely rigid entity,” the researchers said.

Although earlier GPS-based studies had largely suggested that the Indian Plate behaves rigidly, the latest high-precision cGPS observations provide clearer evidence of subtle internal deformation within the plate, the researchers noted.

The findings are expected to contribute substantially to earthquake hazard assessment, geodetic reference frame development, and geodynamic modelling in the Indian subcontinent.