GNSS-Based Monitoring of Present-Day Crustal Deformation in the Hunli Region, Eastern Himalayan Syntaxis, India

Abstract

The Eastern Himalayan Syntaxis (EHS) is one of the most tectonically active regions of the Himalayan orogen, where the Indian, Eurasian, and Burma plates interact through ongoing convergence and crustal deformation. However, geodetic observations from the eastern Arunachal Himalaya remain limited, restricting understanding of present-day tectonic processes. This study aims to monitor present-day crustal deformation in the Hunli region, Arunachal Pradesh, India, using campaign-based Global Navigation Satellite System (GNSS) observations. GNSS data collected between 2008 and 2012 were processed using the GAMIT/GLOBK software package in the International Terrestrial Reference Frame 2014 (ITRF2014), incorporating precise satellite ephemerides and International GNSS Service (IGS) products. Coordinate time-series analysis demonstrates stable station performance suitable for precise geodetic measurements. The estimated horizontal velocity of the Hunli station is 2.26 mm yr⁻¹ towards the northeast (azimuth 45.9°), with eastward and northward velocity components of 1.60 mm yr⁻¹ each. These observations provide new geodetic constraints from a sparsely monitored sector of the Eastern Himalayan Syntaxis and establish a valuable baseline dataset for monitoring present-day crustal deformation in the eastern Arunachal Himalaya. The findings improve understanding of regional crustal kinematics and provide a valuable reference for future geodetic studies, tectonic modelling, and seismic hazard assessment. The study further underscores the importance of expanding continuous and campaign-mode GNSS networks to better characterise crustal deformation and refine geodynamic models of the Eastern Himalayan Syntaxis.