Dynamic Stress Variations in the Indian Sub-continent due to the Kamchatka Earthquake, Mw 8.8, July 29, 2025

ABSTRACT The Kamchatka 2025 Mw 8.8 earthquake is the tenth-largest earthquake recorded worldwide since 1900 and one of the largest historical instrumental events along the Kuril-Kamchatka subduction zone, where the Pacific Plate subducted under the Okhotsk Plate. The heterogeneous rupture, spanning approximately 600 km long and 175–225 km wide, with a maximum slip of 8 m, generated significant dynamic stress changes transmitted across the Indian continent. This study examines the dynamic changes in the stress pattern that occurred throughout the Indian subcontinent as a result of the event. The dynamic stresses, ranging from 24.6 to 26.4 kPa in northeastern India (Arunachal Pradesh, Assam, Manipur, Mizoram, and Nagaland) to 12.0–13.8 kPa in southern peninsular regions (Tamil Nadu, Kerala, Karnataka, and Andhra Pradesh), showing a systematic decrease toward the southwest. The study found that seismically vulnerable areas in Arunachal Pradesh and Kachchh have stress levels far exceeding their corresponding triggering limits, indicating a possibility of seismic activity. On the other hand, the dynamic stresses in the Koyna-Warna region have not reached the triggering threshold. These findings demonstrate the impact of distant megathrust earthquakes on the stress field of the Indian lithosphere. The results also enhance our understanding of long-distance stress transfer, attenuation characteristics, and directional aspects of teleseismic surface waves, having a crucial impact on both seismic hazard evaluation and dynamic triggering potential throughout the Indian subcontinent.