库水位变化对沿岸地倾斜观测的影响——以攀枝花南山地震台为例

Influence of reservoir water level change on shoreside tilt observation——Taking Nanshan Seismic Station in Panzhihua as an example

自2020年11月以来,攀枝花南山地震台多套形变观测仪器以及地龙井、马兰山地震台VP宽频带垂直摆同时段产生固体潮畸变,具体表现为:变化时段相同;畸变持续时间不固定;与EW向相比,NS向干扰较大。分析认为,该畸变系金沙江载荷改变所致。选取3个台站的形变观测数据,采用小波分析和对比分析,探讨江河水位改变对形变观测的荷载影响。结果表明:固体潮畸变与攀枝花金沙水电站出库流量变化存在相关性,即出库流量变化量与固体潮畸变的时间和波幅呈正相关;水库出库流量与观测数据潮汐畸变存在明显相关性,干扰幅度与地震台站和金沙江的相对位置、出库流量变化量存在正相关。此结果可为江河沿岸形变台站日常数据跟踪分析与干扰排除提供参考。

Since November 2020,multiple sets of deformation observation instruments at the Nanshan Seismic Station in Panzhihua,as well as the VP broadband vertical pendulum at the Dilongjing and Malanshan seismic stations,have produced solid tide distortion during the same period.The specific manifestations are:the change period is the same;the duration of distortion is not fixed;compared to the EW direction,the NS direction has greater interference.Analysis suggests that the distortion is caused by changes in the load on the Jinsha River.We select deformation observation data from three stations and use wavelet analysis and comparative analysis to explore the impact of changes in river water levels on deformation observation loads.The results show a correlation between the distortion of solid tide observation and the variation of outflow flow at the Jinsha Hydropower Station in Panzhihua,that is,the variation of outflow is positively correlated with the time and amplitude of solid tide distortion.There is a significant correlation between the outflow flow of the reservoir and the tidal distortion of the observed data,and the interference amplitude is positively correlated with the relative position of the seismic station and the Jinsha River,as well as the change in outflow flow.This result can provide a reference for daily data tracking,analysis,and interference elimination of deformation stations along rivers and banks.