Dynamic Triggering of Earthquakes in Yunnan, China: Insights into the Influence of Distant M>6 Earthquakes and Geothermal Fluids

This study delves into the phenomenon of dynamic triggering of earthquakes in Yunnan, China, a region renowned for its abundant geothermal activity. Through an extensive analysis spanning from 2006 to 2021, we unveil the impact of 13 distant M>6 earthquakes on seismic clusters in the region, emphasizing the unique clustering of these seismic events at specific fault-related locations. Advanced methods, including the Epidemic-Type Aftershock Sequence (ETAS) model, were employed to identify the spatiotemporal patterns of seismic activity before and after these distant M>6 earthquakes. Noteworthy observations highlight the preferential distribution of earthquake clusters at specific fault-related locations, such as fault ends, bends, intersections, and fault step-overs. Some earthquake clusters exhibit clear fluid diffusion processes, validated by increased water temperature in nearby wells. The applied ETAS model underscores a high proportion of forced seismic activity, elucidating the subtle relationship manifested as delayed triggering effects. The results of our study emphasize the association of dynamic triggering with specific fault-related locations, emphasizing the potentially significant role of subsurface geothermal fluids in this process. This research deepens our understanding of seismic activity patterns in the Yunnan region, revealing the intricate interplay between distant M>6 earthquakes, fault dynamics, and geothermal fluid activity.