Ground deformation and fissure activity of the Yuncheng Basin (China) revealed by multiband time series InSAR

Abstract

The Yuncheng Basin (China) is affected by severe land subsidence and ground fissure hazards, which have caused serious land damage and economic losses to the local inhabitants. Due to the lack of long-term continuous monitoring in the region, the trend of land subsidence and fissure activities is unknown, which cannot meet requirements for disaster reduction and disaster prevention. In this study, Envisat ASAR, ALOS PALSAR, and TerraSAR-X are employed to monitor these hazards using time series InSAR methodology. The results showed that there were two obvious subsidence centers occurred in Yuncheng. Compared to the period from 2007 to 2011, the land subsidence rate in the Yuncheng Basin from 2012 to 2015 decreased significantly. Analysis of the differential deformation rate observed by InSAR between the two sides of the ground fissure indicates that fissure activity has weakened in recent years at the cross-section. To explain the phenomena observed by InSAR, FLAC3D was used to study the effect of pumping on ground fissure activity under the condition of pre-existing faults, and the results show that pumping promotes differential activities between two sides of the fault and has a positive impact on the occurrence and the activity of ground fissures. Horizontal rectangular sill with uniform opening model is used to simulate the land subsidence and invert the pumping depth. The results are basically consistent with the local situation.