Colm Jordan

Subglacial bedforms of the last British Ice Sheet

Abstract Please click here to download the map associated with this article. Subglacial bedforms are a characteristic feature of formerly glaciated landscapes. Formed parallel (e.g. drumlins) or transverse (ribbed moraine) to ice flow their preserved distribution is a valuable record of ice sheet configuration. To date these landforms have been underused in Britain such that we have only a simple static view of the flow patterns of the last British Ice Sheet, with glimpses of complexity recorded in just a few locations. Arguably, this is because of the lack of a suitable, ice-sheet scale, map of subglacial bedform distribution. We present the first consistent and countrywide map of subglacial bedforms for Britain produced from systematic mapping. Individual landforms were mapped from relief-shaded renditions of high-resolution elevation data and Landsat TM imagery. The outline or crest-line of each bedform was manually captured by onscreen digitisation directly into a Geographic Information System (GIS) database. Over 39,000 landforms were identified revealing new lineation patterns, multiple instances of cross-cutting/superimposition, and adding additional detail to the known distribution established by local field surveys. A near complete representation of the British subglacial bedform population, the map is a major step towards a detailed model of British Ice Sheet configuration by providing a suitable basis for reconstructing the flow evolution at the ice sheet scale, and a geomorphological framework for the interpretation of sedimentological and stratigraphical data. The map is presented at a scale of 1:525,000.

Intermittent Small Baseline Subset (ISBAS) monitoring of land covers unfavourable for conventional C-band InSAR: proof-of-concept for peatland environments in North Wales, UK

This paper provides a proof-of-concept for the use of the new Intermittent Small Baseline Subset (ISBAS) approach to study ground elevation changes in areas of peat and organic soils in north Wales, which are generally, unfavourable for conventional C-band interferometric applications. A stack of 53 ERS-1/2 C-band SAR scenes acquired between 1993 and 2000 in descending mode was processed with both the standard low-pass SBAS method and ISBAS. The latter revealed exceptional improvements in the coverage of ground motion solutions with respect to the standard approach. The number of identified coherent and intermittently coherent pixels increased by a factor of 26 with respect to the SBAS solution, and extended the coverage of results across unfavourable land covers, particularly for coniferous woodland, bog, acid grassland and heather. The greatest increase was achieved over coniferous woodland, which showed ISBAS/SBAS pixel density ratios above 300. Despite the intermittent nature of the ISBAS solutions, ISBAS provided velocity standard errors generally below 1-1.5 mm/yr, thus preserving good quality of the estimated ground motion rates.

Mapping a Nation’s Landslides: A Novel Multi-Stage Methodology

Through combining new technologies and traditional mapping techniques, the British Geological Survey (BGS) has developed a novel, multi-stage methodology for landslide mapping. 3-D aerial photograph interpretation, variable-perspective 3-D topographic visualisation and field mapping with digital data capture are being used to map the UK’s landslides. The resulting ESRI ArcGIS polygons are published on BGS 1:50,000 geological maps and as digital data products. Data collected during mapping are also uploaded directly into the National Landslides Database maintaining a systematic, nationally-uniform landslide inventory. Repeat monitoring of selected landslides using terrestrial LIDAR and dGPS allows the database to be frequently updated and the proactive Landslide Response Team means that new landslide events can be mapped within days, if not hours, of their occurrence. The long-term aim is to apply this methodology throughout the UK, providing a wealth of data for scientific research and hazard assessment. This methodology is also suitable for application in an international context.

The Value of Outcrop Studies in Reducing Subsurface Uncertainty and Risk in Hydrocarbon Exploration and Production

Field studies over a range of scales have been important in the upstream oil and gas industry for decades. Advances in digital outcrop characterization and data capture, coupled with increased computational capabilities, have resulted in a resurgence in fieldwork; these field studies are required to develop depositional, stratigraphic and structural concepts and provide the data which underpin the current generation of complex, computer generated, 3D subsurface models. These models provide an informed means of benchmarking the subsurface along with a more considered view of subsurface uncertainty and management of the risks identified. The papers in this volume cover safety in the field, frontier basin petroleum system assessment, field appraisal and development including unconventional resources, applications of techniques such as LiDAR and 3D photogrammetry, and uncertainty characterization. The studies were undertaken in diverse locations such as the Faroe Islands, Italy, Algeria, India, the USA and Trinidad; they represent a range of tectonic settings and a wide geological time frame. The spectrum of papers is testament to the value and integral position that fieldwork occupies within the modern hydrocarbon industry.

Developing digital fieldwork technologies at the British Geological Survey

Abstract Geological Surveys are faced with budget constraints and calls for efficiency gains; the effective application of digital techniques is often seen as a route to meeting these demands while increasing the value of outcrop studies and reducing the inherent subsurface uncertainty. The British Geological Survey may be the oldest national Survey in the world (established in 1835); however, developing and implementing new, innovative and efficient technologies for fieldwork is a high priority. Efficient tools for capturing, integrating, manipulating and disseminating outcrop data and information are imperative to enable geoscientists to increase their understanding of geological processes and therefore to reduce subsurface uncertainty and risk. Systems for capturing structured digital field data and for visualizing and interacting with large datasets are increasingly being utilized by geoscientists in the UK and internationally. Augmented reality and unmanned aerial vehicles are amongst the developing technologies being explored for future operational implementation. This paper describes the digital field mapping (BGS·SIGMAmobile) and visualization (GeoVisionary) systems and refers to a case study outlining their contribution to reducing uncertainty and risk in hydrocarbon exploration.

Intermittent SBAS (ISBAS) InSAR with COSMO-SkyMed X-band high resolution SAR data for landslide inventory mapping in Piana degli Albanesi (Italy)

In the context of recent advances in InSAR processing techniques to retrieve higher persistent scatterer and coherent target densities over unfavourable land cover classes, this study tests the Intermittent Small Baseline Subset (ISBAS) approach to update the landslide inventory around the town of Piana degli Albanesi (Italy), an area where only 2% of the land appears suitable to generate radar scatterers based on a pre-survey feasibility assessment. ISBAS processing of 38 ascending mode and 36 descending mode COSMO-SkyMed StripMap HIMAGE SAR scenes at 3m resolution allows identification of ~726,000 and ~893,000 coherent and intermittently coherent pixels for the ascending and descending data stacks respectively. Observed improvements in the number of ISBAS solutions for the ascending mode are greater than 40 times compared to the conventional SBAS approach, not only for urban and rocky terrains, but also rural and vegetated land covers. Line of sight ground motion rates range between -6.4 and +5.5 mm/yr in 2008-2011, although the majority of the processed area shows general stability, with average rates of -0.6 mm/yr in the ascending and -0.1 mm/yr in the descending mode results. Interpretation of the ISBAS deformation rates, integrated with targeted field surveys and aerial photo-interpretation, provides a new and more complete picture of landslide distribution, state of activity and intensity in the test area, and allows depiction of very slow and extremely slow landslide processes even in areas difficult to access, with unprecedented coverage of results.

3D modelling of geology and soils : a case study from the UK

Developments in GIS based technology have greatly aided the routine production of three-dimensional geological maps. Similarly the continued development of airborne remote sensing, geophysics and infrared measurement now provide tools that can assist in the mapping of soil structure and properties rapidly in 2D, 3D and even 4D. Whilst the combined use of such techniques have grown popular for performing site investigations and developing conceptual models of contaminated sites their use in determining and mapping soil has been restricted.

The geological history of Nili Patera, Mars

Nili Patera is a 50 km diameter caldera at the center of the Syrtis Major Planum volcanic province. The caldera is unique among Martian volcanic terrains in hosting: (i) evidence of both effusive and explosive volcanism, (ii) hydrothermal silica, and (iii) compositional diversity from olivine-rich basalts to silica-enriched units. We have produced a new geological map using three mosaicked 18 m/pixel Context Camera digital elevation models, supplemented by Compact Remote Imaging Spectrometer for Mars Hyperspectral data. The map contextualizes these discoveries, formulating a stratigraphy in which Nili Patera formed by trapdoor collapse into a volcanotectonic depression. The distinctive bright floor of Nili Patera formed either as part of a felsic pluton, exposed during caldera formation, or as remnants of welded ignimbrite(s) associated with caldera formation—both scenarios deriving from melting in the Noachian highland basement. After caldera collapse, there were five magmatic episodes: (1) a basaltic unit in the calderas north, (2) a silica-enriched unit and the associated Nili Tholus cone, (3) an intrusive event, forming a ~300 m high elliptical dome; (4) an extrusive basaltic unit, emplaced from small cones in the east; and (5) an extreme olivine-bearing unit, formed on the western caldera ring fault. The mapping, together with evidence for hydrated materials, implies magmatic interaction with subsurface volatiles. This, in an area of elevated geothermal gradient, presents a possible habitable environment (sampled by the hydrothermal deposits). Additionally, similarities to other highland volcanoes imply similar mechanisms and thus astrobiological potential within those edifices.

Futurevolc: A European volcanological supersite observatory in Iceland, a monitoring system and network for the future

FUTUREVOLC is a collaborative project funded through the FP7 Environment Supersite Concept call encompassing 26 partners in 10 countries. The main objectives of FUTUREVOLC are to establish an integrated volcanological monitoring procedure through European collaboration, develop new methods to evaluate volcanic crises, increase scientific understanding of magmatic processes and improve delivery of relevant information to civil protection and authorities. FUTUREVOLC is in the first of its 3.5 year duration, therefore this paper presents aims and expectations rather than results.

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.