Abstract:
The M6.8 Dingri earthquake in Tibet on January 7, 2025, exhibited a spatially extensive and complex aftershock sequence, with a relatively small maximum aftershock magnitude. Additionally, the lack of comparable historical earthquake data in the region posed significant challenges for strong aftershock prediction. This study utilized phase reports from the regional seismic network in Tibet and applied the double-difference relocation method to precisely relocate the Dingri
M6.8 earthquake sequence. The results reveal that the aftershock zone extends along a north-south (NS) trend, spanning approximately 80km in length, with the actual rupture length exceeding empirical estimates. The sequence displays distinct segmentation characteristics, with dense clusters at the northern and southern ends and sparse activity in the central section. The spatial distribution of aftershocks with magnitudes
ML≥4.5 is highly complex, influenced and controlled by multiple factors, including heterogeneous coseismic slip, local stress conditions, fault geometry, tectonic setting, and historical seismic rupture patterns. The largest aftershock recorded was
MS5.0, yielding a magnitude difference of 1.8 from the mainshock. This observation supports the empirical relationship that "larger rupture lengths correlate with greater magnitude differences between the mainshock and its largest aftershock".