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Conference paperReeve MT, Bell RE, Jackson CA-L, 2013,
The influence of Caledonian structures on Late Jurassic faulting offshore western Norway: new insights from 3D seismic reflection data, STUDENT ORAL PRESENTATION PRIZE WINNER
, Tectonic Studies Group Annual Meeting -
Conference paperBell RE, Jackson CA-L, Whipp PS, et al., 2013,
Quantifying the timing and magnitude of fault reactivation in the northern North Sea
, Tectonic Studies Group Annual Meeting -
Conference paperBell RE, McNeill LC, Nixon C, et al., 2013,
Basin evolution and the distribution of strain within the Gulf of Corinthrift
, EGU General Assembly -
Journal articlePotter RWK, Kring DA, Collins GS, et al., 2013,
Numerical modeling of the formation and structure of the Orientale impact basin
, Journal of Geophysical Research: Planets, Pages: n/a-n/a, ISSN: 2169-9100 -
Journal articlePotter RWK, Collins GS, 2013,
Numerical modeling of asteroid survivability and possible scenarios for the Morokweng crater-forming impact
, Meteoritics & Planetary Science, Vol: 48, Pages: 744-757, ISSN: 1945-5100 -
Conference paperVire A, Xiang J, Piggott M, et al., 2013,
Numerical Modelling of Fluid-structure Interactions for Floating Wind Turbine Foundations
, Twenty-third International Offshore and Polar Engineering Conference, Pages: 377-382The aim of this study is to model the interactions between fluids and solids using fully nonlinear models. Non-linearity is important in the context of floating wind turbines, for example, to model breaking waves impacting on the structure and the effect of the solid’s elasticity. In this work, the fluid- and solid-dynamics equations are solved using separate finite-element models, which are coupled at every time step. This enables the mutual interactions between fluids and moving solids to be modelled. Importantly, the coupling algorithm ensures that the action-reaction principle is satisfied at a discrete level, independently of the order of representation of the discrete fields in each model. To the authors’ knowledge, the present algorithm is novel in that it can simultaneously handle (i) non-matching fluid and solid meshes, (ii) different polynomial orders of the basis functions on each mesh, and (iii) different fluid and solid time steps. Results are shown for: (i) a bottom-mounted pile subjected to small-amplitude waves in a numerical wave tank, and (ii) a truncated pile floating at an interface between air and water.
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Journal articleMagee C, Jackson CA-L, Briggs F, 2013,
Lithological controls on igneous intrusion-induced ground deformation, In press
, Journal of the Geological Society of London -
Journal articleAllen PA, Armitage JJ, Carter A, et al., 2013,
The Qs problem: Sediment volumetric balance of proximal foreland basin systems
, SEDIMENTOLOGY, Vol: 60, Pages: 102-130 -
Journal articleJacobs CT, Collins GS, Piggott MD, et al., 2013,
Multiphase flow modelling of volcanic ash particle settling in water using adaptive unstructured meshes
, Geophysical Journal International, Vol: 192, Pages: 647-665Small-scale experiments of volcanic ash particle settling in water have demonstrated that ash particles can either settle slowly and individually, or rapidly and collectively as a gravitationally unstable ash-laden plume. This has important implications for the emplacement of tephra deposits on the seabed. Numerical modelling has the potential to extend the results of laboratory experiments to larger scales and explore the conditions under which plumes may form and persist, but many existing models are computationally restricted by the fixed mesh approaches that they employ. In contrast, this paper presents a new multiphase flow model that uses an adaptive unstructured mesh approach. As a simulation progresses, the mesh is optimized to focus numerical resolution in areas important to the dynamics and decrease it where it is not needed, thereby potentially reducing computational requirements. Model verification is performed using the method of manufactured solutions, which shows the correct solution convergence rates. Model validation and application considers 2-D simulations of plume formation in a water tank which replicate published laboratory experiments. The numerically predicted settling velocities for both individual particles and plumes, as well as instability behaviour, agree well with experimental data and observations. Plume settling is clearly hindered by the presence of a salinity gradient, and its influence must therefore be taken into account when considering particles in bodies of saline water. Furthermore, individual particles settle in the laminar flow regime while plume settling is shown (by plume Reynolds numbers greater than unity) to be in the turbulent flow regime, which has a significant impact on entrainment and settling rates. Mesh adaptivity maintains solution accuracy while providing a substantial reduction in computational requirements when compared to the same simulation performed using a fixed mesh, highlighting the benefits of an adapt
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Book chapterStafford PJ, 2013,
Uncertainties in ground motion prediction in probabilistic seismic hazard analysis (PSHA) of civil infrastructure
, Handbook of seismic risk analysis and management of civil infrastructure systems, Editors: Tesfamariam, Goda, Publisher: Woodhead PublishingGround-motion prediction equations are a critical element of any probabilistic seismic hazard or risk analysis. The total uncertainty in a typical risk analysis is commonly dominated by the uncertainty associated with ground-motion prediction. Within the fields of Engineering Seismology and Earthquake Engineering a lot of attention has been paid to identifying intensity measures that are efficient for predicting response measures, and this efficiency is of great relevance for seismic risk analysis and the development of well-constrained fragility curves. However, the epistemic uncertainties associated with ground motions are still not adequately dealt with, and such uncertainties contribute to the overall predictability of an intensity measure, and hence of an engineering demand parameter. The present chapter provides an overview of the uncertainties that exist within ground-motion prediction and emphasises some of the main components that are not dealt with in a robust manner in current risk analyses. The chapter also highlights recent advancements as well as likely future trends associated with the treatment of uncertainty in ground-motion prediction, with a particular emphasis upon how such uncertainties influence the development of ground-motion models.
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Journal articleKontoe S, Pelecanos L, Potts DM, 2013,
An important pitfall of pseudo-static finite element analysis
, Computers & Geotechnics, Vol: 48, Pages: 41-50Finite Element (FE) pseudo-static analysis can provide a good compromise between simplified methods of dynamic analysis and time domain analysis. The pseudo-static FE approach can accurately model the in-situ stresses prior to seismic loading (when it follows a static analysis simulating the construction sequence) is relatively simple and not as computationally expensive as the time domain approach. However this method should be used with caution as the results can be sensitive to the choice of the mesh dimensions. In this paper two simple examples of pseudo-static finite element analysis are examined parametrically, a homogeneous slope and a cantilever retaining wall, exploring the sensitivity of the pseudo static analysis results on the adopted mesh size. The mesh dependence was found to be more pronounced for problems with high critical seismic coefficients values (e.g. gentle slopes or small walls), as in these cases a generalised layer failure mechanism is developed simultaneously with the slope or wall mechanism. In general the mesh width was found not to affect notably the predicted value of critical seismic coefficient but to have a major impact on the predicted movements.
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Conference paperPuech A, Benzaria O, Thorel L, et al., 2013,
Diagrammes de stabilité cyclique de pieux dans les sables
, Paris, 18th Int. Conf. on Soil Mechanics and Geotechnical Engineering, Publisher: Presses des Ponts, Pages: 2379-2382 -
Journal articleElbeshausen D, Wünnemann K, Collins GS, 2013,
The transition from circular to elliptical impact craters
, Journal of Geophysical Research: Planets, Vol: 118, Pages: 2295–2309-2295–2309, ISSN: 2169-9100Elliptical impact craters are rare among the generally symmetric shape of impact structures on planetary surfaces. Nevertheless, a better understanding of the formation of these craters may significantly contribute to our overall understanding of hypervelocity impact cratering. The existence of elliptical craters raises a number of questions: Why do some impacts result in a circular crater whereas others form elliptical shapes? What conditions promote the formation of elliptical craters? How does the formation of elliptical craters differ from those of circular craters? Is the formation process comparable to those of elliptical craters formed at subsonic speeds? How does crater formation work at the transition from circular to elliptical craters? By conducting more than 800 three-dimensional (3-D) hydrocode simulations, we have investigated these questions in a quantitative manner. We show that the threshold angle for elliptical crater generation depends on cratering efficiency. We have analyzed and quantified the influence of projectile size and material strength (cohesion and coefficient of internal friction) independently from each other. We show that elliptical craters are formed by shock-induced excavation, the same process that forms circular craters and reveal that the transition from circular to elliptical craters is characterized by the dominance of two processes: A directed and momentum-controlled energy transfer in the beginning and a subsequent symmetric, nearly instantaneous energy release.
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Conference paperNixon CW, McNeill LC, Henstock T, et al., 2013,
Basin evolution, organization of faulting and the distribution of displacement within the Gulf of Corinth rift
, AGU Fall Meeting -
Conference paperWilson DJ, McNeill LC, Henstock T, et al., 2013,
Along-strike and down-dip variations in décollement physical properties relative to input parameters
, AGU Fall Meeting -
Conference paperBell RE, Morgan JV, Warner M, 2013,
Recovering physical property information from subduction plate boundaries using 3D full-waveform seismic inversion
, AGU Fall Meeting -
Conference paperBell RE, Jackson CA-L, Elliott G, et al., 2013,
Reconstructing rift geometry to gain insights into major unconformity development associated with Late Jurassic rifting in the Halten Terrace, offshore Norway
, 30th IAS Meeting of Sedimentology -
Conference paperVire A, Xiang J, Piggott M, et al., 2013,
Towards the fully-coupled numerical modelling of floating wind turbines
, 10th Deep Sea Offshore Wind R and D Conference (DeepWind), Publisher: ELSEVIER SCIENCE BV, Pages: 43-51, ISSN: 1876-6102- Author Web Link
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- Citations: 12
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Journal articlePotter RWK, Kring DA, Collins GS, 2013,
Quantifying the attenuation of structural uplift beneath large lunar craters
, Geophysical Research Letters, Vol: 40, Pages: 5615–5620-5615–5620, ISSN: 1944-8007Terrestrial crater observations and laboratory experiments demonstrate that target material beneath complex impact craters is uplifted relative to its preimpact position. Current estimates suggest maximum uplift is one tenth of the final crater diameter for terrestrial complex craters and one tenth to one fifth for lunar central peak craters. These latter values are derived from an analytical model constrained by observations from small craters and may not be applicable to larger complex craters and basins. Here, using numerical modeling, we produce a set of relatively simple analytical equations that estimate the maximum amount of structural uplift and quantify the attenuation of uplift with depth beneath large lunar craters.
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Journal articleGoes S, Armitage J, Harmon N, et al., 2012,
Low seismic velocities below mid-ocean ridges: Attenuation versus melt retention
, JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 117, ISSN: 2169-9313- Author Web Link
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- Citations: 54
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