The capability to predict the final dimensions of an ‘a’a flow-field and the timeline for emplacement is key to effective lava hazard management. Levee breaching and the subsequent generation of secondary flows has been recognised as an intrinsic process in flow-field development. However, the conditions, locations and mechanisms for levee failure are not fully understood and so a multidisciplinary approach was taken utilising field studies of extant flow-fields on Mount Etna and Tenerife, analogue modelling and uniaxial compression tests to investigate levee failure. The experimental results were used to define three stages of flow-field development – lengthening, widening and thickening, a modification of the classification of Kilburn and Lopes (1991). Levee breaching was identified to be a key process by which flow-fields widen during stage two of emplacement. Four mechanisms for breaching are identified, providing a classification system for levee failure. Secondary flows originating from breaching consistently formed at an angle of 30 – 50o to the original channel, significantly contributing to overall flow-field width. Uniaxial compression tests were performed to quantify the mechanical properties of levees. Levee strength was shown to change with direction according to the size, orientation and distribution of vesicles. Samples with vesicle alignment orientated obliquely to the angle of principal stress were consistently weaker. A set of conditions, relating to the mechanical properties of the levee, is therefore identified under which levees are more susceptible to failure. The results of the study have been combined to produce a set of guidelines to the locations and conditions under which levee breaching is more likely to occur, aiding decision making for lava hazard management.

The investigation of neotectonic activity is of high priority when dealing with inaccessible regions where a lack of data and a limited knowledge of the tectonic activity is often typical. There are various individual analyses that investigate features associated with neotectonic activity (for example geoinformatics, geophysical methods and field surveys). However, none of these methods combine low cost techniques based on geospatial and geophysical technologies with field validation of the outcomes. This study offers a methodology that covers all aforementioned approaches for detecting zones of neotectonic activity, linking computer-based observations with actual field observations and geophysical measurements. The combination of satellite imagery and DEM analysis can provide a cost-effective alternative to satellite radar interferometric analysis (InSar) and differential GPS monitoring. Crete is a complex, tectonically active region: an ideal “natural laboratory” to assess the interaction between neotectonic processes and geomorphological processes in landscape evolution and to test the effectiveness of geomorphometric methods for determining zones of neotectonic activity. Geoinformatic and geomorphometric techniques have been used here to assess landscape evolution in tectonically active zones. The results provide new information about the influence of tectonic and erosional processes on geomorphological evolution, with specific insights into the interactions between neotectonic deformation, faulting and drainage networks. Geomorphic indices have been used here to evaluate neotectonic behaviour at regional and local scales, identifying uplifted blocks, valley-floor tilting and zones of relatively intense neotectonic activity. Landsat ETM+ imagery and DEMs were used to discriminate lithological boundaries and identify lineaments. Field and VLF geophysical surveys verified that the lineaments coincide with faults. The GIS based multi-criteria decision analysis (MCDA) was considered as a strong approach to integrate the various factors associated with tectonic activity and to highlight, spatially, the potential zones undergoing active tectonic control.

The timing of onset of modern plate tectonics is currently in conflict. Some believe that it began in the Archaean whereas others prefer a Neoproterozoic onset. At issue is the lack of reliable recorders of changing styles of subduction. Whilst high-pressure rocks (eclogite and high-P granulites) are present in the rock record from Archaean times, low-temperature, high-pressure and ultrahigh- pressure rocks only appear in the Neoproterozoic. This latter association is the hallmark of steep subduction of cold oceanic crust and is central to the argument. Their disappearance from the rock record older than c.600 Ma may be real or it may be a matter of preservation potential. The scope of this project is to investigate this question by the novel use of detrital rutile, which shows great potential as a provenance indicator for high-pressure metamorphism and tectonic settings. The best recorders of subduction are blueschists, which are present in the rock record only to ca. 600 Ma ago. Rutiles in blueschist-facies mafic rocks from Syros and pelitic samples from the Sesia Lanzo Zone have been investigated and results show that the Nb vs. Cr diagram is a reliable tool for high-pressure/low temperature conditions, regardless of the lithology of the source rock. Further, rutiles in ultrahigh-pressure/high temperature rocks from the Dora Maira Massif and the Western Gneiss Complex have been analysed. Grains from the first location plot on the correct area of the chart, but do not correlate with the detrital record, whereas grains from the second location show a mixed Nb/Cr signatures, with eclogites plotting along the metamafic – metapelitic borderline, or even on the pelitic region. This indicates that the discrimination diagram requires special care when using it on high grade rutiles. Provenance studies on Syros and the Sesia Lanzo showed a good host rock – detrital record correlation. Moreover, in the Western Alps, Po River contains a higher percentage of low-temperature rutiles (97%) compared to high temperature grains (3%), that might suggest that the rivers could control this concentration or most likely that the source rocks supply more rutile thus biasing the final population. These results further demonstrate the capability of detrital rutile to provenance highpressure/ low-temperature source rocks, mafic or pelitic, in large riverine systems. The Zr-in-rutile thermometer gives values consistent with previous estimations for both Syros and the Sesia Lanzo samples, using the calibration with a silica activity of 1. The pressure-dependant calibration has a too big correction for lower pressure and temperature conditions. Moreover, quartz-bearing rocks give almost identical temperatures with quartz-free rocks, suggesting that the silica activity does not have a major effect on the thermometer. This latter thermometer has been used for ultrahigh-pressure/high temperature rutiles from Dora Maira and the Western Gneiss Complex, giving slightly lower results for the first location and considerable higher values for most of the samples from the second location. In the first case, a partial re-setting of the zirconium concentration could be the explanation, whereas in the second case, the study concludes that the Zr-in-rutile thermometer gives more consistent results than any exchange geothermometers. Therefore, this thermometer can be safely applied to rocks from blueschist- to granulite-facies rocks, giving good estimations where diffusion did not took place.

Vesuvius in Southern Italy is among the most densely populated active volcanoes on Earth. Although famous for its Plinian eruption that destroyed Pompeii and Herculaneum in AD 79, its recent activity, between 1631 and 1944, was primarily effusive. Data from field studies, analogue modelling and historical accounts are here combined to investigate Vesuvius’ activity during this latest eruptive phase and to identify behavioural trends of value for enhancing emergency responses during future unrest. The focus of this study is on the activity of 1631-1944, and data have been compiled for 183 eruptions during this period. Further data regarding earlier flank eruptions have been incorporated permitting a more comprehensive examination of these infrequent events. Such flank vents have been concentrated on the southern flanks at about 300m above sea level and a mean distance of 4.2 km from the summit. A submarine pit crater, newly correlated here with the 1861 eruption, highlights the potential for vents to form at almost twice the mean distance from the summit and further than previously considered. Analogue studies of magma injection, using a gelatine model, have shown that the vent distribution is consistent with a regional stress field modified by gravitational stresses due to the size and shape of the volcanic edifice. The study of the 1631 to 1944 lava flow-fields shows that lavas from flank vents reached similar lengths to summit and lateral vent flow-fields, all with mean lengths around 4km. Over half of all lava flow-fields extended to beyond 4km from the crater, and so threatened the principal settlements around the foot of the volcano. The flow-fields had typical surface areas of less than 5 km², and approximately a third reached their maximum length within a week. Flank eruptions normally occurred when the summit crater was full of lava and were commonly preceded by three days of elevated seismicity. Such events can thus potentially be forecast with at least a 24-hour warning and, even after an eruption has begun, several days may be available before a settlement is threatened. The design of an effective emergency response to future effusions is thus a feasible objective.

This thesis describes the application of a passive sampler, Diffusive Gradient in Thin Films (DGT), to the measurement of uranium in natural waters. Four resins (Chelex-100, manganese dioxide [MnO2], Diphonix® and MetsorbTM) were trialled with the DGT device. In freshwater environments, the MetsorbTM accumulated uranium in line with the DGT equation for 7 d with an acuracy of 75%; Chelex-100 did not accumulate uranium past 2 d; MnO2 accumulated up to 75% of that predicted by the DGT equation for 4 d; and the Diphonix® accumulated uranium for 7 d with an accuracy of ~100%. None of the resins tested in this study accumulated uranium in a marine setting in line with DGT predicted values past 2 d. The application of DGT to regulatory environmental monitoring schemes was investigated with MetsorbTM. The MetsorbTM DGT devices were deployed for 7 days at a time over a 6 month period at two freshwater field sites. Fluctuations in water chemistry were monitored and the size of the diffusive boundary layer (DBL) was measured. The uranium accumulated by the MetsorbTM DGT showed close agreement with the grab samples. The size of the DBL was found to be significant, particularly in low flow conditions. This study showed that DGT could be used as a tool to both monitor radioncludes in the environment, and to obtain information on the speciation and organic interactions. The lability of uranium-humic acid complexes was also examined in this study. Initial data shows that the uranyl-humic complex is labile in low pH environments, but becomes increasingly kinetically limited the higher the pH and the higher the humic acid:uranium ratio. Data is also presented on the penetration parameter of the uranyl ion into the resin gel layer, and how this can be used to indicate lability. Lability is important in determining bioavailability and potential toxicity of uranium.

Phosphorus is often considered the limiting nutrient in rivers, and reducing concentrations has long been a key policy focus. However, experience has shown that many phosphorus mitigation schemes fail to achieve any improvements in ecological status. The primary aim of this thesis is to identify target phosphorus concentrations that need to be attained to improve river ecology. In-stream flume mesocosms were deployed on three UK rivers of varying levels of nutrient enrichment. Phosphorus concentrations were simultaneously increased and decreased (by iron-dosing) to provide a concentration gradient over which periphyton accrual was examined. This identified whether rivers were phosphorus limited, and allowed a phosphorus-limiting threshold to be quantified. The effects of nitrogen, and combined phosphorus and nitrogen addition were also examined. The River Lambourn study simultaneously manipulated light intensity and nutrient concentrations, demonstrating shading to have benefits in improving periphyton quality as a food resource and in reducing periphyton accrual. The near-pristine River Rede showed that increase in river phosphorus concentration had no effect on periphyton growth rate, but that there was a 3.5-fold increase in growth rate when phosphorus and nitrogen were added simultaneously, demonstrating the presence of sequential nutrient co-limitation. By repeating a 2005 study on the River Frome, the 2012 study proved that phosphorus-limiting thresholds change in response to changing river nutrient concentrations. Examination of changes in community structure by the trophic diatom index and flow cytometry provide evidence for a lower ecological threshold in rivers of ca. 30 μg l-1. A fast repetition rate fluorometer was used to assess phytoplankton stress across the Thames catchment throughout an algal bloom and data was examined alongside water quality data. Bloom development and collapse was primarily controlled by residence time and, secondarily, phosphorus concentration. This thesis has challenged traditional beliefs that phosphorus is the limiting nutrient in freshwater ecosystems and has provided insights on how to best meet the requirements of the Water Framework Directive and improve ecological status.

This body of work presents the research and publications undertaken under a general theme of computer-based modelling and analysis in engineering geology. Papers are presented on geotechnical data management, data interchange, Geographical Information Systems, surface modelling, geostatistical methods, risk-based modelling, knowledge-based systems, remote sensing in engineering geology and on the integration of computer applications into applied geoscience teaching. The work highlights my own personal contributions and publications under this theme as well as collaborations and output emanating from PhD co-supervisions which have included the following projects: A geotechnical and geochemical characterisation of dry oil lake contaminated soil in Kuwait; Dust dispersion monitoring and modelling; Geotechnical properties of chalk putties; The application of airborne multispectral remote sensing and digital terrain modelling to the detection and delineation of landslides on clay dominated slopes of the Cotswolds Escarpment; Domestic property insurance risks associated with brickearth deposits; Development of a knowledge-based system methodology for designing solid waste disposal sites in arid and semi-arid environments; GIS Techniques as an aid to the assessment of earthquake triggered landslide hazards; The application of GIS as a data integrator of pre-ground investigation desk studies for terrain evaluation and investigation planning; The influence of clay mineralogy pore water composition and pre-consolidation pressure on the magnitude of ground surface heave due to rises in groundwater level. My publication record comprises; Pathfinder and seminal papers; Papers from co-supervised PhD programmes; Pedagogic contributions; Encyclopaedia entries; International collaborations; Technical authorship and support; Other published contributions; Confidential development and technical reports and Internal briefing papers.

The Paleogene succession in the Hampshire Basin, southern England is poorly described in terms of its engineering properties.The nature and distribution of landslides across the basin is also poorly described. This thesis describes work carried out to better understand the engineering properties of the Paleogene succession and how this affects landsliding in the region. A new engineering stratigraphy for the Paleogene strata of the Hampshire Basin has been constructed by collating available geological and geotechnical data, including examination of available exposures, database information, published and non-published literature. Similarly landslides across the basin were examined by field mapping, image interpretation and literature review and a new landslide inventory was produced. This new stratigraphy was utilised in a basin wide model of landslide occurrence using an infinite slope based methodology in a GIS. This new model was used to improve the landslide inventory, resulting in the identification of a total of 429 new landslides, a threefold increase on previous knowledge. Results indicate that landslide identification may be greatly enhanced if a geotechnical model is incorporated in the investigation. The research shows that it is appropriate to construct geological models based upon an engineering stratigraphy. For this study area, this model was tested by its incorporation into a slope stability analysis that could then be tested against the results of image interpretation and field surveys. This could be important for other studies where geotechnical information may be incomplete or where it is difficult to collect new data. This may have important implications for similar studies elsewhere.

By integrated stratigraphy of the Zumaia and Sopelana sections in northern Spain, a detailed astronomical time scale is obtained for the Maastrichtian. The cyclic alternations of hemipelagic limestones and marls at Sopelana and Zumaia display the range of periodicities of eccentricity-modulated precession. The rhythmic bedding pattern is primarily caused by variations in siliciclastic supply and to a lesser extent to variations in biological productivity, both of which controlled by eccentricity modulated precession through its influence on the hydrological cycle. Together, the Zumaia and Sopelana sections span almost the entire Maastrichtian, and encompass thirteen 405-kyr cycles, spanning a total duration of 5.3 Myr. Consecutive 405-kyr minima in the lithological and geophysical data records are tuned to successive 405-kyr minima in the new La2011 eccentricity solution. Assuming a K/Pg boundary age of 65.97 Ma, orbitally tuned ages of biostratigraphic and magnetostratigraphic events are obtained. The bases of Chrons C29r and C30n have been reliably established at Zumaia and their astronomically tuned ages are in good agreement with previous studies. Data from Sopelana provide a refinement of the age of the base of Chron C31r. Planktonic foraminifera and calcareous nannoplankton data from Zumaia, and new calcareous nannoplankton data from Sopelana allow for worldwide correlation of the cyclostratigraphy of the Basque country. Additionally, the orbitally tuned bulk carbonate carbon isotope curve displays a remarkable amplitude of variation. Strong oscillations in δ13C seem regularly paced by the 405-kyr periodicity of eccentricity modulated precession. Sharp negative shifts associated with falls in sea-level occur at regular intervals of ~1.2 Myr. A new global correlation of carbon isotope stratigraphies is presented, with an astronomically tuned age model based on the cyclostratigraphy of Zumaia and Sopelana and site 762C (Exmouth Plateau). The Late Campanian/Maastrichtian carbon isotope correlation scheme displays a series of trends and excursions that can be observed across the different depositional settings. These results suggest that the 405-kyr cycle of eccentricity, and potentially longer periodicities, paced the latest Cretaceous climate and carbon cycle.