摘要
Abstract
The North China region,which is characterized as a typical intracontinental exten-sional rift zone and an area with strong seismic activity,exhibits notable regional differences in vertical deformation patterns.These disparities are attributed to the combined tectonic effects of the subduction of the Pacific Plate to the east and the collision of the Indian Plate to the west,along with excessive groundwater extraction.To quantitatively analyze the vertical deformation characteristics of this region,we collected 1406 GPS observation datasets covering a twenty-year period from 1999 to 2019,and then processed the data by using a unified high-precision processing method.As a result,we acquired a vertical deformation velocity field with high spa-tial resolution.
The results reveal distinct deformation patterns across different geological units:The North China plain and Huaihe plain mainly experience subsidence,with maximum subsidence rates of approximately 70 mm/a and 50 mm/a,respectively.In contrast,the Taihangshan,Lüliangshan,Sulu orogenic belt,and Yanshan exhibit uplift patterns with rates ranging from 0.1 mm/a to 4 mm/a.Notably,the vertical deformation patterns from GNSS stations in the Shanxi rift zone and Taihangshan areas present an intriguing dichotomy.We also noticed that,some GNSS sta-tions on soil show subsidence,while those on bedrock show uplift,suggesting that the obser-ved subsidence is likely attributable to excessive groundwater extraction rather than tectonic movements.
This study is the first to integrate meteorological GNSS observation data into vertical deformation research,significantly improving the spatial resolution of vertical deformation ve-locity fields in the North China Craton.The most pronounced subsidence appears in North China plain,forming a NE-SW trending subsidence belt that coincides with fault orientations.However,due to the lack of GNSS bedrock stations in these areas,accurately quantifying the respective contributions of tectonic and non-tectonic to the observed vertical deformation remains challenging and warrants further investigation.
The Shanxi Plateau,Yanshan,and Sulu orogenic belt predominantly exhibit uplift tenden-cies.The data from the GNSS stations on bedrock confirm that the Shanxi Graben does not pos-sess tectonic-induced subsidence characteristics.The localized subsidence observed at certain stations within the graben is likely influenced by groundwater extraction effects on soil-based GNSS stations,rather than being indicative of actual tectonic movement.
This comprehensive analysis provides valuable insights into the intricate interaction between tectonic forces and anthropogenic activities in shaping the vertical deformation patterns of the North China region,offering a robust foundation for subsequent geodynamic studies and land subsidence monitoring in this tectonically active area.关键词
华北/GNSS/垂直形变/构造运动Key words
North China/GNSS/vertical deformation/tectonic movement分类
地球科学
