Mechanism of Land Subsidence of Plateau Lakeside Kunming City Cluster (China) by MT-InSAR and Leveling Survey

Abstract

Li, S.M.; Wang, Z.M.; Yuan, L.W.; Li, X.X.; Huang, Y.Z., and Guo, R., 2020. Mechanism of land subsidence of plateau lakeside Kunming city cluster (China) by MT-InSAR and leveling survey. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 666-675. Coconut Creek (Florida), ISSN 0749-0208.The Kunming city cluster (KCC) is located around the lakeside of Dianchi Lake, a plateau lake in Kunming Basin southwest of China, which is of complex geological structures and evolutionary history, and belongs to an earthquake fault depression area, where faults are developed and crustal stability is poor. Influenced by regional uplift and continuous subsidence of lakeside areas, the land subsidence characteristics of KCC are quite complex. The subsidence mechanism shows multi-inducement and multi-source property. In this paper, the land subsidence ranges, subsidence rate and subsidence spatio-temporal variation pattern of KCC were analyzed, mainly based on multi-temporal interferometry synthetic aperture radar (MT-InSAR), supplemented by leveling survey data, from 1986 to 2018. The effects of various controlling factors on land subsidence were studied respectively, such as geological structure, stratigraphic distribution, groundwater exploitation, and loads on the ground due to infrastructure construction and human activities, and the internal mechanism and response relation between the subsidence and the factors were studied too. The controlling factors and variation pattern of land subsidence in KCC were identified. The results have shown that the land subsidence of KCC is mainly affected by the tectonic activity in this area, fault basin landform sediments provide conditions for the development and speed up of land subsidence, and the previous land subsidence areas were closely related to the excessive exploitation of groundwater. However, in recent years, the subsidence areas expand continuously due to increases of loads from human activities. By analyzing the controlling factors and spatio-temporal variation pattern of land subsidence in the study areas, this paper has preliminarily revealed the land subsidence mechanism, which will provide reasonable theoretical reference and practical guidance for identifying and eliminating the potential land subsidence hazards and urban development planning in the plateau lakeside city cluster.