Showing papers by "Alastair Ruffell published in 2013"

Spatial statistics to estimate peat thickness using airborne radiometric data

Abstract: Soil carbon stores are a major component of the annual returns required by EU governments to the Intergovernmental Panel on Climate Change. Peat has a high proportion of soil carbon due to the relatively high carbon density of peat and organic-rich soils. For this reason it has become increasingly important to measure and model soil carbon stores and changes in peat stocks to facilitate the management of carbon changes over time. The approach investigated in this research evaluates the use of airborne geophysical (radiometric) data to estimate peat thickness using the attenuation of bedrock geology radioactivity by superficial peat cover. Remotely sensed radiometric data are validated with ground peat depth measurements combined with non-invasive geophysical surveys. Two field-based case studies exemplify and validate the results. Variography and kriging are used to predict peat thickness from point measurements of peat depth and airborne radiometric data and provide an estimate of uncertainty in the predictions. Cokriging, by assessing the degree of spatial correlation between recent remote sensed geophysical monitoring and previous peat depth models, is used to examine changes in peat stocks over time. The significance of the coregionalisation is that the spatial cross correlation between the remote and ground based data can be used to update the model of peat depth. The result is that by integrating remotely sensed data with ground geophysics, the need is reduced for extensive ground-based monitoring and invasive peat depth measurements. The overall goal is to provide robust estimates of peat thickness to improve estimates of carbon stocks. The implications from the research have a broader significance that promotes a reduction in the need for damaging onsite peat thickness measurement and an increase in the use of remote sensed data for carbon stock estimations.

Environmental and criminal geoforensics

Abstract: Geological techniques are widely used in two aspects of serious criminal investigations: (1) the search for clandestine burial sites, based on near-surface geophysics or through the detection of decomposition signals and (2) the analysis of trace evidence to identify its source location or test the possible association between the trace evidence and a known location of an offence. Although geoforensics is used in such investigations world-wide there are still considerable gaps in the published literature. In addition, there is increasing concern regarding the illegal release of wastes either into the atmosphere, water courses or on to the land surface, and a growing realization that the techniques used in criminal forensics are equally useful in the investigation of environmental crime. This book bridges the gap between environmental and criminal geoforensics with conceptual, methodological and case study contributions. This demonstrates the significant potential that geoforensics holds for investigating and regulatory officers.

Environmental and criminal geoforensics: an introduction

Abstract: Many subdisciplines within the Earth Sciences make use of either geophysical instruments to investigate the subsurface environment or use analytical methods to determine the origin, or provenance, of geological materials. These same instruments and analytical methods can be used either directly, or adapted to suit, the acquisition of data that pertain to a wide range of forensic science investigations. Such approaches, as discussed below, are generally not new but, in recent years, there has been a significant resurgence globally in the application of geological and geophysical methods to aid forensic investigations. Traditionally, such methods were used in forensic investigations related to serious criminal cases such as terrorism, murder, abduction and serious sexual assaults, and to a lesser extent in the investigation of cases of fraud and theft. But with increasing concern into the environmental impact of human activity, with the release of contaminants into the atmosphere, hydrosphere and lithosphere, and their potential uptake into the biosphere, there has been an increased amount of environmental legislation. In turn, there has commonly been an increase in the costs associated with the legal discharge or disposal of wastes. Consequently, it is unsurprising that the illegal discharge and disposal of wastes has also increased. Identifying the distribution, impact and source of such waste materials can, in part, be addressed through the application of geological techniques, in much the same way as used traditionally, for example, in the investigation of murder cases. The diversification of the use of geological techniques into the investigation of environmental crime will, potentially, significantly increase the range of investigations in which geologists may be asked to assist but will also lead to a new array of research questions to be addressed, hence the need for this Special Publication. In this short introduction, the aim is to place the current work into its broad historical context and summarize the key findings from the papers presented within this volume. The papers within this Special Publication were presented at two separate conferences in 2010: the Third International Soil Forensics Conference held at Long Beach California USA and organized by the SFI Group; and a conference on Environmental and Criminal Forensics, organized by the Forensic Geoscience Group of the Geological Society of London, and held at Burlington House, London, in December 2010.

Issues and opportunities in urban forensic geology

Abstract: Abstract Geological trace evidence including, for example, soil, sand and rock dust has been examined using a wide range of analytical techniques. Whilst such materials are common in rural locations, in urban areas, such geological materials are often perceived to be restricted to parks, recreational areas, gardens and waste ground. However, both geological materials and the wide range of analytical methods used to characterize them are much more applicable to the whole urban environment than is generally realized, with the main differences being the types and amounts of sample analysed and the methods adopted. The range of geological applications can be summarized as those deployed at the broad (decimetres–kilometres) to small (millimetres–decimetres) scale. The broad spatial variation in soil, roadway, water, buildings materials, and wind- or water-borne particles can be contrasted with the variation in urban materials from dwellings to streets or gardens and parks, along with the micro-spatial and stratigraphical variation in each. In addition, geological principles and techniques that have not been used before can be applied to urban materials to provide comparisons of material that were not previously achievable, or to add a further proxy to established methods. The latter point is demonstrated with a case study using X-ray diffraction and QEMSCAN® of a criminal case where building plaster with peculiar qualities could be compared between a suspect's vehicle and plaster present along the escape route from a murder scene.

Solid and drift geology in forensic investigations

Abstract: Abstract Forensic geology, forensic geoscience and geoforensics (see the text for definitions) are largely concerned with searches for buried objects or the use of sediment and soil analysis as evidence. Geophysics, remote sensing, geostatistics, geochemistry and geomorphology are considered part of these disciplines. Traditional outcrop geology is not often considered, with very few publications considering the role of mapped and logged geology. This work comprises a review of the few published works, followed by a range of case studies that demonstrate how traditional, outcrop-scale drift and solid geology can be used in forensic geology. These include: using geology in the search for buried explosives and human remains; the logging of solid and drift geology for analysis of disputed rock quality; and modelling groundwater flow from an illegal landfill site. Geological mapping may assist in limiting a search area or in understanding what failed in a search or forensic investigation. The scale of forensic geology discussed bridges the gap between the two traditions of forensic geology outlined above: that of searching large areas of ground and trace evidence analysis.