Volume Change of Groundwater in Langfang Region Derived from Multi-Temporal InSAR

This paper use multi-temporal InSAR(Multi-Temporal InSAR,MTI) technology to obtain the high-precision velocity field of Langfang city by two track SAR dataset between 2007 and 2010.The results show that the maximum rate of ground subsidence in Langfang is 76.0 mm/yr;there is a very significant subsidence funnel in downtown.Based on the deformation results,this paper uses free stress volume strain changes model to inverse the volume change of groundwater.The maximum peak volume change is 1.15×10-4/a,and the total volume change of groundwater is-5.54 billion m3/a.