The Anninghe Fault stretches roughly 200 kilometres along the Anning River valley in southern Sichuan, forming a central link in the great boundary that separates the Sichuan-Yunnan block from the stable South China block. It connects the Xianshuihe Fault to the north with the Zemuhe and Xiaojiang faults to the south.
This left-lateral strike-slip fault slips at roughly 6 millimetres per year and runs through steep, mountainous terrain along a deeply incised river corridor. Geologists have identified it as a significant seismic gap, a locked segment that has not ruptured in a major earthquake for centuries and may be storing substantial strain.
Historical records document large earthquakes near magnitude 7 along the Anninghe trace, and its position within one of China's most seismically active corridors makes it a priority for monitoring. The combination of a long quiet interval and steady tectonic loading marks it as a potential source of a future strong earthquake.