An application of iterative principal component analysis on analyzing the regional groundwater level and stratum elastic-deformation

The groundwater level is a comprehensive response of the external stimuli of the aquifer, such as rainfall and river recharge, and is one of the main factors affecting the formation deformation. The spatiotemporal analysis of stratum elastic deformation identifies different stimulus sources and their influence on groundwater level changes, as well as the influence of groundwater level changes on stratum elastic deformation. In addition to the numerical test to verify the correctness of the analysis process, this study uses the daily water level observation data of each aquifer in Yunlin area of Taiwan to conduct principal component analysis to explore the influence of rainfall and river water level on the variation of groundwater level in each aquifer. Furthermore, based on the magnetic ring layered subsidence observation well data, the iterative principal component analysis was used to explore the influence of the variation of the groundwater level in each layer on the elastic deformation of each layer.

The research results show that the first principal component of the groundwater level in each aquifer in the Yunlin area can fully reflect the impact of rainfall on the groundwater level, and the residual water level affected by rainfall can be deducted to analyze the impact of the river water level. The results show that the shallower water level Compared with the deeper aquifers 2-2 and 3, layers 1 and 2-1 have a more significant effect on the river water level. In the analysis of formation compression deformation, the correlation analysis between the principal component of groundwater level and the principal component of formation deformation shows that there is a high negative correlation between the water level change of each aquifer and the formation deformation, which is in line with the physical mechanism of groundwater level and formation deformation. The above analysis results show that principal component analysis, combined with the analysis process of this study, can indeed identify and isolate the influence of various external stimuli to the groundwater level, and can also obtain the main changes in the elastic deformation of the formation, which can be used as the basis for further water resources planning and analysis. Important reference.