Ground infrastructure monitoring in coastal areas usingtime-series inSAR technology:the case study of Pudong International Airport,Shanghai

Shanghai Pudong International Airport(PDIA),with its east side built along the coast with weak geological conditions,is prone to uneven foundation settlement due to the consolidation and compression of soil and erosion of coastal tides,affecting the safe operation of the airport.Therefore,it is crucial to conduct dynamic subsidence monitoring within the airport,especially in the runway area.29 scenes of ascending track Sentinel-1A radar images from August 2016 to June 2018 are selected to perform surface deformation inversion based on PS-InSAR and improved SBAS-InSAR for PDIA and its around coastal area.Through cross-validation,the reliability of the time-series InSAR technique for dynamic monitoring of surface deformation of coastal zone infrastructures is confirmed.The results show severely uneven settlement.By combining the monitoring results with the local geological and hydrological dataset,the driving factors of differential deformation of the infrastructures are analyzed,including stratigraphic geological conditions,ground loadings,foundation treatment methods,water erosion,and groundwater level changes.Finally,the time-series deformation characteristics and the causes of PDIA’s runway are emphasized based on the PS deformation results.This case provides a reference for the safety management of critical infrastructure in coastal areas using advanced InSAR technique.

Monitoring of ground deformation in Liulin district,China using InSAR approaches

Coalbed methane(CBM)exploration generally refers to a technique that extracts natural gas from coal beds.The development of CBM in Liulin,China,has experienced a significantly growth period during the past two decades.Previous research mainly focused on the coal geological background or CBM technique itself,while time series InSAR(TS-InSAR)technique was conducted in this work to study the potential land deformation induced by CBM extraction from 2003 to 2011.In total,21 ALOS-1 PALSAR images(acquired from 22 December 2006 to 2 January 2011)and 14 ENVISAT ASAR scenes(captured between 29 October 2003 and 7 November 2007)were used.The TS-InSAR outcome revealed that the annual deformation rates were ranging from 15 to−40 mm yr−1 over the study region.Then the time series deformation evolutions were analysed over 8 CBM sites(No.4 coal seam)out of 20,and the subsidence rates between 1.9 and−6.5 mm yr−1 were derived.In addition,the average subsidence rate and standard deviation among these eight measurements were−3.0 and 2.6 mm yr−1 respectively,suggesting that these CBM extraction sites were quite stable and no obvious subsidence had been observed during this eight-year period.