2017 Jiuzhaigou earthquake
Northern Sichuan is in an area where there is a lot of earth movement.  In this area, the Tibetan Plateau is next to the Yangtze Plate with great pressure forming faults along the edges.  Jiuzhaigou County is in the Min Mountains, a range that was formed where these faults meet.  The disastrous 1879 Gansu earthquake had its earthquake centre about 65 kilometres to the east of where the 2017 Jiuzhaigou earthquake happened.  The places with lots of mountains to the south of Jiuzhaigou County were the earthquake centre of the 2008 Sichuan earthquake that resulted in tens of thousands of deaths.