Land Surface Displacement Geohazards Monitoring Using Multi-temporal InSAR Techniques

China has been affected by some of the world’s most serious geological disasters and experiences high economic damage every year.Geohazards occur not only in remote areas but also in highly populated cities.In the framework of the Dragon-432365 Project,this paper presents the main results and the major conclusions derived from an extensive exploitation of Sentinel-1,ALOS-2(Advanced Land Observing Satellite 2),GF-3(Gao Fen Satellite 3),and latest launched SAR(Synthetic Aperture Radar),together with methods that allow the evaluation of their importance for various geohazards.Therefore,in the scope of this project,the great benefits of recent remote sensing data(wide spatial and temporal coverage)that allow a detailed reconstruction of past displacement events and to monitor currently occurring phenomena are exploited to study different areas and geohazards problems,including:surface deformation of mountain slopes;identification and monitoring of ground movements and subsidence;landslides;ground fissure;and building inclination studies.Suspicious movements detected in the different study areas were cross validated with different SAR sensors and truth data.

Early Cretaceous transpressional and transtensional tectonics straddling the Sulu orogenic belt,East China

The Sulu orogenic belt(SOB)separates the North and South China blocks in East Asia and formed during Triassic continent-continent collision.However,late Mesozoic post-collisional exhumation is poorly understood due to lack of surface evidence for Paleo-Pacific subduction and associated effects.This paper interprets the tectonic history of the SOB using detrital zircon age data from Early Cretaceous sedimentary units along with previously published geochronologic and geochemical data to reconstruct sedimentological and tectonic history.Detrital zircon age distributions obtained from sedimentary units include a 2.0 Ga subpopulation that appears only in turbidite units to the southeast.This sediment probably derived from the Yangtze Block.Terrestrial facies from the Jiao-Lai basin to the northwest appear to derive from the North China Block.Geochronologic and geochemical data indicate that Early Cretaceous,post-collisional volcanism was compositionally bimodal(mafic-felsic)with associated intrusive activity that peaked at 120 Ma.Seismic images of northerly regions of the study area indicate this occurred in an extensional setting.Sedimentary facies and field structural analyses revealed an unconformity interpreted to reflect rapid uplift with NW SE compression to the south.Given observed sinistral movement along the Tan-Lu fault,we interpret northwest and southeast regions of the SOB as experiencing transtensional and transpressional tectonics,respectively,driven by continuous subduction of the Paleo-Pacific Plate.Intrusion of the Late Yanshannian granitoids marked the final formational stage of this unique tectonic setting.

Integration of satellite remote sensing data in underground coal fire detection:A case study of the Fukang region,Xinjiang,China

Xinjiang in China is one of the areas worst affected by coal fires.Coal fires cannot only waste a large amount of natural resources and cause serious economic losses,but they also cause huge damage to the atmosphere,the soil,the surrounding geology,and the environment.Therefore,there is an urgent need to effectively explore remote sensing based detection of coal fires for timely understanding of their latest development trend.In this study,in order to investigate the distribution of coal fires in an accurate and reliable manner,we exploited both Landsat-8 optical data and Sentinel-1A synthetic aperture radar(SAR)images,using the generalized single-channel algorithm and the InSAR time-series analysis approach,respectively,for coal fire detection in the southern part of the Fukang region of Xinjiang,China.The generalized single-channel algorithm was used for land surface temperature information extraction.Meanwhile,the timeseries InSAR analysis technology was employed for estimating the surface micro deformation information,which was then used for building a band-pass filter.The suspected coal fire locations could then be established by a band-pass filtering operation on the obtained surface temperature map.Finally,the locations of the suspected coal fires were validated by the use of field survey data.The results indicate that the integration of thermal infrared remote sensing and radar interferometry technologies is an efficient investigation approach for coal fire detection in a large-scale region,which would provide the necessary spatial information support for the survey and control of coal fires.