Research On The Structural Deformation Of North And Middle Segment Of Honghe Fault Based On PS-InSAR

The Honghe fault is located at the southeast margin of the Tibet Plateau.It is a large-scale fault zone with an important position,and Its motion features possesses obviously segmentation.The tectonic of northern segment has been active up from the Quaternary to now,and had occurred many earthquakes with Ms?6.The seismic activity is less occurred in the middle and south sections,so this research of characteristics of present crustal deformation have great significance to take evaluation about regional seismic hazard assessment.Because of the difficulty in observing the near-field deformation of the fault zone by useing GPS,this paper research the characteristics of crustal deformation in the north and middle segment of the Honghe fault by using the PS-InSAR technology and the SAR data with Sentinel-1,ENVISAT and ALOS-1.According to the geological and geomorphological characteristics of the north and middle regions and the limits of data coverage,this paper selects a region as a study area,and process the SAR data of the study area by use PS-InSAR technology to obtain the line-of-sight deformation in the study area.Moreover,it researches characteristics of spatio-temporal deformation of fault zone near-field crust and inversion of slip rate of fault zone.In order to solve the problem of line-of-sight ambiguity in InSAR,this paper attempts to combination with SAR data processes results of up-and down-orbit of the study area and decompose deformation rate of the line-of-sight into east-west and vertical directions,validate the GPS data in the region.The main results are as follows:1.From 2007 to 2017,the crustal deformation in the northern segment of the Honghe fault zone shows that the north plate of the fault was uplifted and the south plate was subsided.According to the observation mode of the satellite orbit,the south plate of the northern segment of the fault zone are moved from west to east,and north plate of the northern segment of the fault zone are move west.From 2007 to 2017,the deformation rate of LOS directions of the northern section of the Honghe fault zone was between-5.5 and 3.5 mm/a,and the relative velocity between of the northern and southern plates was 8.25 mm/a.From 2008 to 2017,the deformation rate of LOS directions in the middle section of the fault zone was between-4~3.5mm/a,the relative velocity between of the plates in the north and south of the fault zone was 5mm/a,and the south side of the fault zone is subsided,the northern side of the fault zone is uplifted except for the subsidence in the area of Nanhua and Chuxiong.2.This paper inversion of slip rate of fault zone by use the PS deforming rate and the GPS data of Honghe fault,vand respectively,it invert out the slip rate of north and middle of the fault zone was 4.6mm / a and 3.4mm/a by use PS point,it invert out the slip rate of north and middle of the fault zone was 4.3mm / a and 2.9mm / a by use GPS date,and the inversion results are consistent.It takes comparison with the lifting track results of PS-InSAR combine with the test about deformation rate of the line-of-sight into east-west and vertical directions of LOS directions and GPS results,the error between the two within 1mm / a.3.This paper take profile analysis to fault zone by using LOS directions rate graph and GPS data shows that: 10 ~ 15 km on both sides of the northern section of the fault zone is the deformation transformation zone and the middle section is the deformation transformation zone within 5 ~ 10 km on both sides of the fault zone.The middle section of the Honghe fault zone is creep slip by fitting the trend line across faults zone.