Recurrence of large earthquakes along the southern Xainza-Dinggye rift and comparison with the 7 January 2025, Mw7.1 Tingri earthquake, southern Tibet

Abstract

Southern Tibet is dissected by seven NS-trending rifts bounded by normal faults absorbing ∼9 mm/yr of EW extension over ∼1000 km. While large earthquakes are rare in this remote region, the occurrence of the 7 January 2025, M_w7.1 Tingri earthquake on a fault with a known long-term throw rate, presents a great opportunity to compare co-seismic deformation with long-term fault behavior. Here, we first report our main post-earthquake field observations along the seismogenic Dingmuco fault (0.9 m of co-seismic vertical offset) and Lagoi fault within the southern Xainza-Dinggye rift. We then compare these observations with late Quaternary throw and extension rates along the Dingmuco fault, derived from ¹⁰Be surface-exposure dating and topographic measurements of cumulative offsets. Our results yield throw rate and extension rates of 1.1(+0.5/−0.2) and 1.1 ± 0.3 mm/yr, respectively, over the past 19 ± 5 ka. This suggests that this relatively short fault plays a substantial role, accommodating roughly 12 % of the total EW extension across southern Tibet. These findings imply an average recurrence interval of ∼800 years for earthquakes of similar magnitude along the Dingmuco fault.