基于形变观测分析鲜水河断裂带现今运动分段特征OA

Based on the structural characteristics of the Xianshuihe fault zone,this study divides the five sections of Luhuo,Daofu,Qianning,Zheduotang,and Kangding-Moxi,and quantitatively re-veals the horizontal slip rate and kinematic characteristics of each section through multi-source obser-vation data of cross-fault leveling,baseline/ranging,and horizontal creep.The results show that the whole Xianshuihe fault zone is dominated by left-lateral strike-slip mode from 1982 to 2024.The strike-slip rates of Juwo and Xialatuo in Luhuo section are-0.9 mm/a and-2.86 mm/a,and the cu-mulative strike-slip displacements are 40 mm and 130 mm,which are significantly higher than the ac-tivity intensity of Gelu and Xuxu stations.The strike-slip rates of Goupu and Goupu creep stations in Daofu-Qianning section are-0.97 mm/a and-0.58 mm/a,and the cumulative displacement shows a linear growth trend.The horizontal displacement of Longdengba and Laoganning stations is small,and the local fault zone is weakly sinistral.The Zheduotang observation site in the Kangding-Moxi sec-tion shows a+0.2 mm/a dextral strike-slip,while the Yulin observation site maintains a stable left-lateral strike-slip of-0.12 mm/a,and its deformation has significant seasonal fluctuations(amplitude of about 1.5 mm to 2.3 mm).The cross-fault leveling of the Anshun site shows continuous tensile normal fault activity,and the linearity of the movement trend reaches 0.933 and 0.824,respectively.The results of segmented comparison show that the activity intensity of the northwestern section is significantly higher than that of the southeastern section,and the vertical movement shows that the thrust of the northern section and the normal fault activity of the southern section are structural inver-sion.The segmentation difference is related to the fault geometry and the physical properties of the medium.The medium strength of the conversion layer in the northwest section may be lower than that in the southeast section,which is easy to trigger slip and lead to shorter earthquake recurrence period.Combined with the regional stress field,it is found that the locking degree of the Xianshuihe fault zone has changed in different periods,showing that the fault in the northwest section is more active than that in the southeast section,and the locking is weak.At the same time,after the Wenchuan Ms8.0 earthquake,the Lushan Ms7.0 earthquake,and the Luding Ms6.9 earthquake,the extrusion rate of the Bayan Har block to the Sichuan basin accelerated,which affected the far-field left-lateral strike-slip rate of the Xianshuihe fault and the accumulation rate of fault slip deficit,which in turn led to the difference in the stress and strain accumulation rate of each segment on the Xianshuihe fault zone.