The driving of the Yigong earthquake swarm and the seasonal variations

In this study, the factors that drive the Yigong earthquake swarm in the southeastern part of the Tibetan Plateau are investigated. By analyzing the temporal and spatial characteristics of the earthquake swarm, the Xixingla fault is identified as the primary agent in driving the genesis of the earthquake swarm and the seasonal variations in seismic activity. As a significant branch of the southeastern Jiali fault, the Xixingla fault is subjected to high stress stemming from the northward compressive forces of the eastern Himalayan syntaxis. Additionally, climate variations amplify freeze-thaw cycles in glaciers and increase riverine erosion, leading to increased topographical steepness and greater fracturing of rock masses. During the monsoon season, elevated temperatures and heavy precipitation result in substantial glacial melt, causing rapid accumulation of meltwater and rainfall in Yigong Lake. This phenomenon increases the surface load acting on the fault zone, whereas infiltrating water increases pore pressure along rock fractures and faults. The stress accumulated along the fault ultimately triggers rupture, resulting in the formation of an earthquake swarm. Furthermore, the increased stress on the fault due to the 2017 Milin earthquake contributed to a higher frequency of seismic events in the Yigong region. Understanding the hydrogeological and tectonic conditions in Yigong and its vicinity is essential for predicting future seismic activity and developing effective disaster prevention strategies.