Luke Bateson

The application of the Intermittent SBAS (ISBAS) InSAR method to the South Wales Coalfield, UK

Satellite radar interferometry is a well-documented technique for the characterisation of ground motions over large spatial areas. However, the measurement density is often constrained by the land use, with best results obtained over urban and semi urban areas. We use an implementation of the Small Baseline Subset (SBAS) methodology, whereby areas exhibiting intermittent coherence are considered alongside those displaying full coherence, in the final result, to characterise the ground motion over the South Wales Coalfield, United Kingdom. 55 ERS-1/2 Synthetic Aperture Radar (SAR) C-band images for the period between 1992 and 1999 are processed using the ISBAS (Intermittent Small BAseline Subset) technique, which provides 3.4 times more targets, with associated measurements than a standard SBAS implementation. The dominant feature of the observed motions is a relatively large spatial area of uplift. Uplift rates are as much as 1 cm/yr. and are centred on the part of the coalfield which was most recently exploited. Geological interpretation reveals that this uplift is most likely a result of mine water rebound. Collieries in this part of the coalfield required a ground water to be pumped to enable safe coal extraction; following their closure pumping activity ceased allowing the water levels to return to equilibrium. The ISBAS technique offers significant improvements in measurement density ensuring an increase in detection of surface motions and enabling easier interpretation.

DInSAR estimation of land motion using intermittent coherence with application to the South Derbyshire and Leicestershire coalfields

Differential interferometric synthetic aperture radar (DInSAR) is a recognized remote-sensing method for measuring the land motion occurring between two satellite radar acquisitions. Advanced DInSAR techniques such as persistent scatterers and small baseline methods are excellent over urban and rocky environments but generally poor over more rural and natural terrain where the signal can be intermittently good and bad. Here, we describe the Intermittent Small Baseline Subset (ISBAS) method, which appears to improve results over natural, woodland and agricultural terrain. This technique uses a multi-looked, low-resolution approach, which is particularly suitable for deriving the linear components of subsidence for large-scale deformations. Application of the ISBAS method over a coal mining area in the UK indicates that it is able to significantly improve upon a standard small baseline approach.

Remote Sensing for Natural or Man-Made Disasters and Environmental Changes

Natural and man-made disasters have become an issue of growing concern throughout the world. The frequency and magnitude of disasters threatening large populations living in diverse environments, is rapidly increasing in recent years across the world due to demographic growth, inducing to urban sprawls into hazardous areas. These disasters also have far-reaching implications on sustainable development through social, economic and environmental impact. This chapter summarises three scientific contributions from relevant experiences of the British Geological Survey and the Federico II University of Naples, where remote sensing sensors have been playing a crucial role to potentially support disaster management studies in areas affected by natural hazards. The three cases are: the landslide inventory map of St. Lucia island, tsunami-induced damage along the Sendai coast (Japan) and the landslide geotechnical characterization in Papanice (Italy). For each case study we report the main issue, datasets available and results achieved. Finally, we analyse how recent developments and improved satellite and sensor technologies can support in overcoming the current limitations of using remotely sensed data in disaster management so to fully utilize the capabilities of remote sensing in disaster management and strength cooperation and collaboration between relevant stakeholders including end users.

A Methodology to Detect and Characterize Uplift Phenomena in Urban Areas Using Sentinel-1 Data

This paper presents a methodology to exploit the Persistent Scatterer Interferometry (PSI) time series acquired by Sentinel-1 sensors for the detection and characterization of uplift phenomena in urban areas. The methodology has been applied to the Tower Hamlets Council area of London (United Kingdom) using Sentinel-1 data covering the period 2015–2017. The test area is a representative high-urbanized site affected by geohazards due to natural processes such as compaction of recent deposits, and also anthropogenic causes due to groundwater management and engineering works. The methodology has allowed the detection and characterization of a 5 km2 area recording average uplift rates of 7 mm/year and a maximum rate of 18 mm/year in the period May 2015–March 2017. Furthermore, the analysis of the Sentinel-1 time series highlights that starting from August 2016 uplift rates began to decrease. A comparison between the uplift rates and urban developments as well as geological, geotechnical, and hydrogeological factors suggests that the ground displacements occur in a particular geological context and are mainly attributed to the swelling of clayey soils. The detected uplift could be attributed to a transient effect of the groundwater rebound after completion of dewatering works for the recent underground constructions.

Identifying natural and anthropogenically-induced geohazards from satellite ground motion and geospatial data: Stoke-on-Trent, UK

Determining the location and nature of hazardous ground motion resulting from natural and anthropogenic processes such as landslides, tectonic movement and mining is essential for hazard mitigation and sustainable resource use. Ground motion estimates from satellite ERS-1/2 persistent scatterer interferometry (PSI) were combined with geospatial data to identify areas of observed geohazards in Stoke-on-Trent, UK. This investigation was performed within the framework of the EC FP7-SPACE PanGeo project which aimed to provide free and open access to geohazard information for 52 urban areas across Europe. Geohazards identified within the city of Stoke-on-Trent and neighbouring rural areas are presented here alongside an examination of the PanGeo methodology. A total of 14 areas experiencing ground instability caused by natural and anthropogenic processes have been defined, covering 122.35 km2. These are attributed to a range of geohazards, including landslides, ground dissolution, made ground and mining activities. The dominant geohazard (by area) is ground movement caused by post-mining groundwater recharge and mining-related subsidence (93.19% of total geohazard area), followed by landsliding (5.81%). Observed ground motions along the satellite line-of-sight reach maxima of +35.23 mm/yr and −22.57 mm/yr. A combination of uplift, subsidence and downslope movement is displayed. ‘Construction sites’ and ‘continuous urban fabric’ (European Urban Atlas land use types) form the land uses most affected (by area) by ground motion and ‘discontinuous very low density urban fabric’ the least. Areas of ‘continuous urban fabric’ also show the highest average velocity towards the satellite (5.08 mm/yr) and the highest PS densities (1262.92 points/km2) along with one of the lowest standard deviations. Rural land uses tend to result in lower PS densities and higher standard deviations, a consequence of fewer suitable reflectors in these regions. PSI is also limited in its ability to identify especially rapid ground motion. As a consequence the supporting geospatial data proved especially useful for the identification of landslides and some areas of ground dissolution. The mapped areas of instability are also compared with modelled potential geohazards (the BGS GeoSure dataset).