基于GNSS数据的河北地区形变特征

Deformation Characteristics in Hebei Region based on GNSS Data

利用河北及周边地区的GNSS观测数据,得到河北地区2010—2021年水平运动速度场;根据GNSS测站分布和地震危险性对河北地区进行分区,分别计算各分区的应变时序结果,总结河北地区应变结果的时空变化特征,并与其他前兆观测手段进行分析对比。结果表明:①在水平运动方向上,省内8个测站在全球参考框架下运动方向均为东南向运动,扣除区域内整体运动后,省内测站相对水平运动不显著,6个测站量值在1 mm/a以内,反映出该区域整体水平运动比较平稳,年变化量不大;②从应变分区情况来看,晋冀豫交界地区2018年主压应力有所减弱,冀鲁交界地区自2016年主压应力有所增大,京津冀交界地区2016年主压应力有所减小,唐山、天津地区2016年主张应力有所减小,张渤带的西段张家口地区2016年主压应变下降减缓、2018年主张应力增大,晋冀蒙交界地区自2017年下半年主压应力减小。上述GNSS处理结果表明,河北地区整体运动较为平稳,内部区域存在一定的相对运动和时间上的调整。

Using GNSS observation data in Hebei and surrounding areas,the velocity field of horizontal motion in Hebei region from 2010 to 2021 was obtained.According to the distribution of GNSS stations and seismic risk,Hebei region was divided into different regions,and the temporal and spatial variation characteristics of strain results in Hebei region were summarized and compared with other precursor observation methods.The results show that:in the horizontal movement direction,the movement direction of the 8 stations in the province is in the southeast direction in the global frame of reference;after deducting the overall movement within the region,the relative horizontal movement of the measuring stations in the province is not significant,and the magnitude of the 6 measuring stations is within 1 mm/yr,reflecting that the overall horizontal movement of the region is relatively stable,with little annual change.From the perspective of strain zoning,the principal compressive stress in the border area of Shanxi、Henan and Hebei province decreased in 2018.The principal compressive stress in the border area between Hebei and Shandong has increased since 2016.The principal compressive stress in the beijing-Tianjin-Hebei border area decreased in 2016.The principal tension stress in Tangshan and Tianjin decreased in 2016.In the western part of the Zhangjiakou-Bohai fault and the Zhangjiakou area,the decrease of the principal pressure strain slowed down in 2016,and the principal tension stress increased in 2018.Since the second half of 2017,the principal compressive stress in the border area between Shanxi,Hebei and Inner Mongolia has decreased.The above GNSS processing results show that the overall movement in Hebei is relatively stable,and there is a certain relative movement and time adjustment in the internal region.