## 2 Tectonic Setting
### Fault Characterization
#### 2.4.2. Xiaozhongdian-Daju Fault  
The Xiaozhongdian-Daju fault is the southeast segment of the Deqin-Zhongdian-Daju fault. It starts from Xiaozhongdian and passes through Majiacun, Daiu, and Dadong to the banks of the Jinsha River (Figure 4a). This fault is characterized by a right-lateral strike slip with strikes at 300-320\({}^{\circ}\), a dip angle of 70-80\({}^{\circ}\), and a total length of approximately 80 km [44; 45; 46]. Geological and geomorphic field studies indicated that the fault was most recently active from the late Pleistocene to the Holocene, and it has average horizontal and vertical slip rates of 1.7-2.0 mm/a and 0.6-0.7 mm/a, respectively [46]. Many historical earthquakes were caused by this fault, including the 1966 Xiaozhongdian \(M_{\text{S}}\) 6.4 earthquake,  
Figure 3: (**a**) Seismotectonic map of the Daiu–Lijiang fault. The red lines represent the location of the Daiu–Lijiang fault, and the red circle represent the epicenter of the 1996 Lijiang \(M_{\text{S}}\)7.0 earthquake. (**b**) Seismic depth profiles along the Daiu–Lijiang fault (\(M_{\text{S}}\geq 1.0\) earthquakes are from 1 January 1981 to 28 February 2018). The circles denote the earthquakes, and the colors denote the focal depth. The gray dashed line shows the 90% seismicity cutoff depth within 10 km of the fault. (**c**) Source model of the Daiu–Lijiang fault. The blue stars represent the rupture starting points (SPs), and the red areas represent the largest asperity; the subfault size is 2 km \(\times\) 2 km [19]. the 1933 Xiaozhongdian \(M\) 6\(\frac{1}{4}\) earthquake, and multiple \(M\) 5-5.9 earthquakes southeast of Daju. Based on the maximum credible earthquake of \(M_{\text{W}}\) 7.3 and Equations (1) and (2), the rupture length and width of the Xiaozhongdian-Daju fault were calculated to be 80 and 22.5 km, respectively. Earthques within 10 km of the Xiaozhongdian-Daju fault along its strike direction were projected onto a profile (Figure 4b). The 90% cumulative depth distribution was 15 km. Combining the rupture width calculated using the empirical relationship with the seismic depth distributions along the fault, a rupture width of 22 km was determined. [PERSON] et al. [45] studied the stratigraphic landform, scarp landform, surface rupture, typical fault profile, and river terrace along the Zhongdian-Daju fault. The southeastern section of this fault can be divided into the Majiacun-Daju and Daju-Dadong segments. The Majiacun-Daju segment is a right-lateral strike-slip fault with a normal faulting component, and its vertical and horizontal slip rates since the late Pleistocene have been 0.4-0.8 and 1.5-2.4 mm/a, respectively. The Daju-Dadong segment is dominated by a right-lateral strike slip with a normal faulting component, and its vertical slip rate since the late Cenozoic has been 0.1 mm/a. [PERSON] et al. [45] proved that the Majiacun-Daju segment has been strongly active since the Holocene, while the Daju-Dadong segment has had no obvious horizontal dislocations in the alluvial deposits since the Holocene. Thus, the Holocene activity of the  
Figure 4: (**a**) Seismotectonic map of the Xiaozhongdian–Daju fault. The red lines represent the location of the Xiaozhongdian–Daju fault, and the red circles represent two earthquakes occurred on this fault. (**b**) Seismic depth profiles along the Xiaozhongdian–Daju fault (\(M_{\text{S}}\geq 1.0\) earthquakes) are from January 1, 1981, to February 28, 2018. The circles denote earthquakes, and the colors denote the focal depth. The gray dashed line shows the 90% seismicity cutoff depth within 10 km of the fault. (**c**) Source model of the Xiaozhongdian–Daju fault. The blue stars represent the SPs, and the red areas represent the largest asperity; the subfault size is 2 km \(\times\) 2 km [19]. Daju-Dadong segment is considered weak in terms of the dislocation amount and slip rate. The 1966 Xiaozhongdian \(M_{\text{S}}\) 6.4 earthquake occurred on the Xiaozhongdian-Daju fault at a focal depth of 12 km.