Damaging earthquakes of the Eastern Indian subcontinent and seismic hazard potential: insights from palaeoseismology

Abstract

ABSTRACT The ongoing Indo-Eurasian convergence leads to great megathrust earthquakes in the Himalayan region, affecting the life and infrastructure of the world’s most densely populated areas adjoining the Himalaya. The ~2500-km long Himalayan arc has experienced several earthquakes having magnitude greater than Mw 7.5 during the last millennium. While palaeoseismic and fault slip-rate studies have gained pace during the last few decades in the Western and Central Himalayan regions, the Eastern Himalaya and contiguous regions remain understudied. Even though geological evidence of great earthquakes in 1697, 1714, and 1950 CE has been reported in the Eastern Himalaya, the lateral extent of their rupture is still debated due to limited and sparse palaeoseismic studies. Furthermore, the segmentation of the eastern Himalaya raises concerns about the role of sub-surface transverse structures in controlling the rupture propagation of large to great earthquakes. Hence, we have compiled all the palaeo-earthquake studies carried out in the eastern part of the Himalayan convergent plate margin of the Indian Subcontinent and identified the potential gap areas with the slip deficit, which are capable of generating Mw > 8 earthquakes in the future. This study aims to provide a foundation for future palaeo-earthquake studies, which are crucial in understanding the earthquake recurrence and the strain release pattern in the region.