## 5 Discussion  
In this study, we examined the Holocene activity characteristics of the middle segment of the Jinshajiang fault zone using methods such as high-resolution image interpretation, seismic geological surveys, and trenches. In Hongdong Village, the latest activity of the Huotaping fault resulted in deformation of the synchronous deposition and faulted the top sandy soil layer in the geological profile. This coincided with the latest earthquake event found by [PERSON] et al. [6]; this event occurred on the fault at 770 \(\pm\) 30 a BP. In Yarigong Town, using the ages of the upper and lower terraces of the displaced river, the Late Quaternary slip rate of the Yarigong fault was constrained to between 4.5 \(\pm\) 0.5 mm/a and 2.6 \(\pm\) 0.3 mm/a, with an average slip rate of 3.6 \(\pm\) 0.6 mm/a. This was consistent with the result of [PERSON] et al. [6]. Trenches TC1 at Buge and TC2 at Nidou both recorded three paleoseismic events. The stratigraphy-age model and paleoseismic sequences were calibrated using OxCal v4.4.4 [42,43]. The occurrence ages of the three paleoseismic events revealed in trench TC1 at Buge were constrained to 6745-3848, 3742-1899, and 1494-1112 cal BP (Figure 13a). In addition, three paleoseismic events were identified in trench TC2 at Nidou dated to 32,566-29,430, 24,056-22,990, and 2875-2723 cal BP (Figure 13b). The recurrence interval of the two latest paleoseismic events revealed in trench TC2 was as long as 20,000 years. The absence of major earthquake records during such a long period may indicate missing paleoseismic events. The unconformable contacts between units U4 and U3 and between units U5 and U6 revealed in trench TC2 indicate prolonged erosion periods without records of paleoseismic events. Even during periods of erosion, it is possible to be a relatively weak or calm seismic activity period. Therefore, it is believed that the behaviors of the major earthquakes on the Yarigong and Ciwu faults are not consistent. The Yarigong fault indicates active large earthquake events during the Holocene, while the large earthquake activity on Ciwu fault has been relatively stable. The Jinshajiang fault zone is a complex tectonic suture belt with multi-phase activity and is characterized by multiple sets of parallel or intersecting faults. This fault zone is thought to have distinct thrust characteristics [1,5,44]. However, our study found that the Jinshajiang fault zone's main active fault with Late Quaternary activity exhibited predominantly strike-slip motion. Both the geological profiles and the trenches revealed that the main faults mostly exhibited a component of normal faulting and did not show significant thrusting motion characteristics. The occurrence of many normal-fault earthquakes in the Jinshajiang fault zone confirmed the existence of these normal faults. GPS observations also  
Figure 13: Paleoseismic sequences of the Yarigong and Ciwu faults, the raw carbon ages of which were calibrated using OxCal 4.4.4 [42]. (**a,b**) are the paleoseismic sequences revealed in trench TC1 and TC2, respectively. showed significant extensional movement of the block in the Batang-Litang region [45]. In the Jinshajiang fault zone, the Late Quaternary horizontal slip rate of the NE-trending Batang fault was 2-3 mm/a [1, 6, 46], and the horizontal slip rates of the NNE-trending Yarigong fault and the NE-trending Ciwu fault were 2.6-4.5 mm/a and 2.5 \(\pm\) 0.5 mm/a, respectively. Although we did not obtain the horizontal slip rates of the NNW-trending Hongjunshan and Hetaoping faults, one can speculate that the single slip rates of the two faults should be less than those of the above-mentioned main faults. The variation in the strikes and horizontal slip rates of the main faults may be the main reason for the development of secondary EW-trending normal faults and relevant earthquakes in the Jinshajiang fault zone.