Publications

Search or filter publications

Filter by type:

Filter by publication type

Filter by year:

to

Results

  • Showing results for:
  • Reset all filters

Search results

  • Software
    Piggott MD, 2014,

    Fluidity

    Fluidity is an open source, general purpose, multi-phase computational fluid dynamics code capable of numerically solving the Navier-Stokes equation and accompanying field equations on arbitrary unstructured finite element meshes in one, two and three dimensions.It is used in a number of different scientific areas including geophysical fluid dynamics, computational fluid dynamics, ocean modelling and mantle convection. It uses a finite element/control volume method which allows arbitrary movement of the mesh with time dependent problems, allowing mesh resolution to increase or decrease locally according to the current simulated state. It has a wide range of element choices including mixed formulations.Fluidity is parallelised using MPI and is capable of scaling to many thousands of processors. Other innovative and novel features are a user-friendly GUI and a python interface which can be used to calculate diagnostic fields, set prescribed fields or set user-defined boundary conditions.
  • Journal article
    Jacobs CT, Avdis A, Gorman GJ, Piggott MDet al., 2014,

    PyRDM: A Python-based Library for Automating the Management and Online Publication of Scientific Software and Data

    , Journal of Open Research Software, Vol: 2, ISSN: 2049-9647
  • Journal article
    Mannie AS, Jackson CA-L, Hampson GJ, 2014,

    Shallow-marine reservoir development in extensional diapir-collapse minibasins: An integrated subsurface case study from the Upper Jurassic of the Cod terrace, Norwegian North Sea

    , AAPG BULLETIN, Vol: 98, Pages: 2019-2055, ISSN: 0149-1423
  • Journal article
    Rotevatn A, Jackson CA, 2014,

    3D structure and evolution of folds during normal fault dip linkage

    , Journal of the Geological Society, Vol: 171, Pages: 821-829

    Understanding the 3D geometry and evolution of extension-related folds is important because they may document the geometry and evolution of the associated faults, influence sediment routing and accommodation development, and may represent targets for hydrocarbon exploration or CO2 storage. Previous work on extension-related folds has largely been restricted to a 2D plane of observation; in this study we use 3D seismic reflection data from the Gulf of Suez, Egypt to determine the 3D geometry and evolution of fault-parallel folds during dip linkage of a vertically segmented extensional fault array that is locally decoupled across a salt-bearing interval. The 3D geometry of individual faults in the array and adjacent hanging-wall folds varies along strike; rollover structures occur above listric faults, whereas fault-bend folds occur above faults that have a ramp–flat–ramp geometry. Quantitative analysis of fault–fold attributes (e.g. fold amplitude) and the growth history of the fault array indicate that fault shape is controlled by the style of dip linkage, which in turn is controlled by the lateral separation of sub- and supra-salt segments prior to linkage. Small lateral separation yields a relatively subtle change in the overall convexity of the listric fault, whereas larger lateral separation results in a ramp–flat–ramp fault geometry, with the layer-parallel detachment lying within the salt. This study provides a link between fault spacing, style of dip linkage, final fault shape and, ultimately, the style of hanging-wall folding in mechanically layered stratigraphy. Our study indicates that 3D seismic reflection data have the ability to provide us with new 3D insights into the variability of, and controls on, the geometry and evolution of fault-related folds.
  • Conference paper
    Ghail RC, Skipper J, Mason PJ, 2014,

    Identification of Ground Engineering Hazards in London Through the Use of Predictive 4D Geomodelling Tools

    , Switzerland, Engineering Geology for Society and Territory, Publisher: Springer International Publishing, Pages: 907-911

    Unexpected ground conditions are responsible for a number of engineering problems and hazards across London. A major reason for the unexpected nature of these events is the historical proprietary approach to site investigation, which has restricted knowledge transfer and inhibited the development of a London-wide geological context. Recent changes mean that much of these data are now accessible in the public domain for site investigation and useful in predicting the engineering hazards resulting from complex and variable geology. We advocate applying predictive 4D modelling to better constrain geological structures, facies, fissures and groundwater flow, and adopting an iterative approach that both informs local site models and updates the regional context. Reverse normal faulting, indicative of basin inversion, pull-apart structures and periglacial scour/pingo features are identified in a pilot study regional model. Applying this model to a small site investigation predicted otherwise unexpected faulting, generating horizontal fissuring that causes water to flow along the length of the fault system. Widely adopting this approach in London and other urban areas may substantially reduce the risk of unexpected ground hazards.
  • Journal article
    ITOI T, STAFFORD PJ, KANEKO M, SATO Iet al., 2014,

    21146 Stochastic Ground Motion Simulation for Probabilistic Seismic Risk Assessment

    , Summaries of technical papers of annual meeting, Vol: 2014, Pages: 291-292, ISSN: 1883-9363
  • Journal article
    Parkinson SD, Hill J, Piggott MD, Allison PAet al., 2014,

    Direct numerical simulations of particle-laden density currents with adaptive, discontinuous finite elements

    , GEOSCIENTIFIC MODEL DEVELOPMENT, Vol: 7, Pages: 1945-1960, ISSN: 1991-959X
  • Journal article
    Wu M-C, Liu J, Cosgrove J, Mason PJ, Yan H, Chang W-Yet al., 2014,

    Modelling of Yingxiu-Seichuan fault zone based on refined DInSAR data of 2008 Wenchuan earthquake

    , TECTONOPHYSICS, Vol: 630, Pages: 193-207, ISSN: 0040-1951
  • Conference paper
    Camara A, Nguyen K, Ruiz-Teran AM, Stafford PJet al., 2014,

    Comfort in Slender Bridges Subjected to Traffic Loading and Hammering Effects

    , 37th International IABSE Symposium
  • Journal article
    Bierman PR, Coppersmith R, Hanson K, Neveling J, Portenga EW, Rood DHet al., 2014,

    A cosmogenic view of erosion, relief generation, and the age of faulting in southern Africa

    , GSA Today, Vol: 24, Pages: 4-11, ISSN: 1052-5173

    Southernmost Africa, with extensive upland geomorphic surfaces, deep canyons, and numerous faults, has long interested geoscientists. A paucity of dates and low rates of background seismicity make it challenging to quantify the pace of landscape change and determine the likelihood and timing of fault movement that could raise and lower parts of the landscape and create associated geohazards. To infer regional rates of denudation, we measured10Be in river sediment samples and found that south-central South Africa is eroding ∼5 m m.y.-1, a slow erosion rate consistent with those measured in other non-tectonically active areas, including much of southern Africa. To estimate the rate at which extensive, fossil, upland, silcrete-mantled pediment surfaces erode, we measured10Be and26Al in exposed quartzite samples. Undeformed upland surfaces are little changed since the Pliocene; some have minimum exposure ages exceeding 2.5 m.y. (median, 1.3 m.y.) and maximum erosion rates of <0.2 m m.y.-1(median, 0.34 m m.y.-1), consistent with no Quaternary movement on faults that displace the underlying quartzite but not the silcrete cover. We directly dated a recent displacement event on the only recognized Quaternary-active fault in South Africa, a fault that displaces both silcrete and the underlying quartzite. The concentrations of10Be in exposed fault scarp samples are consistent with a 1.5 m displacement occurring ca. 25 ka. Samples from this offset upland surface have lower minimum limiting exposure ages and higher maximum erosion rates than those from undeformed pediment surfaces, consistent with Pleistocene earthquakes and deformation reducing overall landscape stability proximal to the fault zone. Rates of landscape change on the extensive, stable, silcretized, upland pediment surfaces are an order of magnitude lower than basin-average erosion rates. As isostatic response to regional denudation uplifts the entire landscape at several meters per million years, valleys
  • Conference paper
    Milbury C, Johnson BC, Melosh HJ, Collins GS, Blair DM, Soderblom JM, Zuber MTet al., 2014,

    THE EFFECT OF POROSITY AND DILATANCY ON THE GRAVITY SIGNATURE OF CRATERS ON THE MOON.

    , 77th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A283-A283, ISSN: 1086-9379
  • Journal article
    Reeve MT, Bell RE, Jackson CA-L, 2014,

    Origin and significance of intra-basement seismic reflections offshore western Norway (vol 171, pg 1, 2014)

    , JOURNAL OF THE GEOLOGICAL SOCIETY, Vol: 171, Pages: 737-737, ISSN: 0016-7649
  • Journal article
    Leinov E, Jackson MD, 2014,

    Experimental measurements of the SP response to concentration and temperature gradients in sandstones with application to subsurface geophysical monitoring

    , JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 119, Pages: 6855-6876, ISSN: 2169-9313
  • Journal article
    Jacobs CT, Piggott MD, 2014,

    Firedrake-Fluids v0.1: numerical modelling of shallow water flows using a performance-portable automated solution framework

    , Geoscientific Model Development Discussions, Vol: 7, Pages: 5699-5738, ISSN: 1991-9611
  • Journal article
    Molkenthin C, Scherbaum F, Griewank A, Kuehn N, Stafford Pet al., 2014,

    A Study of the Sensitivity of Response Spectral Amplitudes on Seismological Parameters Using Algorithmic Differentiation

    , Bulletin of the Seismological Society of America, Vol: 104, Pages: 2240-2252, ISSN: 0037-1106

    Response spectra are of fundamental importance in earthquake engineeringand represent a standard measure in seismic design for the assessment of structuralperformance. However, unlike Fourier spectral amplitudes, the relationship of responsespectral amplitudes to seismological source, path, and site characteristics is notimmediately obvious and might even be considered counterintuitive for high oscillatorfrequencies. The understanding of this relationship is nevertheless important forseismic-hazard analysis. The purpose of the present study is to comprehensively characterizethe variation of response spectral amplitudes due to perturbations of the causativeseismological parameters. This is done by calculating the absolute parametersensitivities (sensitivity coefficients) defined as the partial derivatives of the modeloutput with respect to its input parameters. To derive sensitivities, we apply algorithmicdifferentiation (AD). This powerful approach is extensively used for sensitivity analysisof complex models in meteorology or aerodynamics. To the best of our knowledge, ADhas not been explored yet in the seismic-hazard context. Within the present study, ADwas successfully implemented for a proven and extensively applied simulation programfor response spectra (Stochastic Method SIMulation [SMSIM]) using the TAPENADEAD tool. We assess the effects and importance of input parameter perturbations on theshape of response spectra for different regional stochastic models in a quantitative way.Additionally, we perform sensitivity analysis regarding adjustment issues of groundmotionprediction equations.
  • Journal article
    Greve S, Paulssen H, Goes S, van Bergen Met al., 2014,

    Shear-velocity structure of the Tyrrhenian Sea: Tectonics, volcanism and mantle (de)hydration of a back-arc basin

    , EARTH AND PLANETARY SCIENCE LETTERS, Vol: 400, Pages: 45-53, ISSN: 0012-821X
  • Journal article
    Winsor K, Carlson AE, Rood DH, 2014,

    <sup>10</sup>Be dating of the Narsarsuaq moraine in southernmost Greenland: Evidence for a late-Holocene ice advance exceeding the Little Ice Age maximum

    , Quaternary Science Reviews, Vol: 98, Pages: 135-143, ISSN: 0277-3791

    In southernmost Greenland near Narsarsuaq, the terminal Narsarsuaq moraine was deposited well outside of a historical Little Ice Age (LIA) moraine adjacent to the modern ice margin. Using 10Be surface exposure dating, we determine Narsarsuaq moraine abandonment at 1.51±0.11ka. A second set of 10Be ages from a more ice-proximal position shows that ice has been within or at its historical (i.e., LIA) extent since 1.34±0.15ka. Notably, Narsarsuaq moraine abandonment was coincident with climate amelioration in southern Greenland. Southern Greenland warming at ~1.5ka was also concurrent with the end of the Roman Warm Period as climate along the northern North Atlantic sector of Europe cooled into the Dark Ages. The warming of southern Greenland and retreat of ice from the Narsarsuaq moraine is consistent with studies suggesting possible anti-phase centennial-scale climate variability between northwestern Europe and southern Greenland. Other southernmost Greenland ice-margin records do not preclude a pre-LIA ice-margin maximum, potentially concurrent with a Narsarsuaq advance prior to ~1.51ka, but also lack sufficient ice-margin control to confirm such a correlation. We conclude that there is a clear need to further determine whether a late-Holocene pre-LIA maximum was a local phenomenon or a regional southern Greenland ice maximum, and if this advance and retreat reflects a regional fluctuation in climate. © 2014.
  • Journal article
    Xu S, Freeman SPHT, Rood DH, Shanks RPet al., 2014,

    <sup>26</sup>Al interferences in accelerator mass spectrometry measurements

    , Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, Vol: 333, Pages: 42-45, ISSN: 0168-583X

    The identification of interferences to 26Al was conducted with a 5 MV tandem accelerator mass spectrometer. In addition to 9Be 1+, 17O2+ and 35Cl4+ ions observed previously, this study confirmed existence of the most significant interference 37Cl4+ continuum ion to 16 MeV 26Al3+ by measuring primary standard mixed with Cl with various 37Cl/35Cl ratios. The 37Cl- ions were formed by 37Cl16O- molecular-dissociation before the injection magnet, resulting in -0.7% of 26Al- magnetic rigidity. Subsequently, the 37Cl4+ ions have ME/q2 value that differ from 26Al3+ by -0.1%. These allow the 37Cl - and 37Cl4+ to simultaneously pass through injection magnet, analytical magnet and high-energy analyser, and finally reach the detector with 26Al3+. Further investigations on high charge states (26Al5+ and 26Al7+) indicate that the problem of interferences is generic. That is, interferences closest to 24 MeV 26Al5+ ions include 10B 2+, 16O3+, 35Cl7+ and 37Cl7+ ions, while 32 MeV 26Al7+ ions may be interfered by 7Li2+, 16O 4+, 18O5+, 35Cl9+ and 37Cl9+. However, it remains unclear that 37Cl continuum events observed in 26Al3+-AMS do not exist in 26Al5+ and 26Al7+-AMS operations. © 2014 Elsevier B.V. All rights reserved.
  • Journal article
    Jackson CAL, Jackson MPA, Hudec MR, Rodriguez CRet al., 2014,

    Internal structure, kinematics, and growth of a salt wall; insights from 3D seismic reflection data

    , Geology, Vol: 42, Pages: 307-310

    The detailed kinematics of natural salt walls remain elusive because such structures are typically poorly exposed at outcrop, only partly exposed in mine workings, and diapiric salt is typically poorly reflective in seismic data. We use three-dimensional seismic and borehole data from offshore Brazil to investigate how structural styles vary along strike within a spectacularly well-imaged salt wall. Deformed layering in the salt allows us to map complex, seismic-scale structures in the wall; within the wall's relatively simple external shape is a range of previously undocumented structural styles produced by: (1) initial upwelling and formation of a wall-parallel anticline due to regional extension and differential overburden load, (2) breaching of the anticline, Rayleigh-Taylor overturn, and emplacement of an intrasalt allochthonous sheet driven by a density inversion, and (3) internal thrusting of the mature diapir caused by regional compression. This study is arguably the first detailed documentation of the internal structure and kinematics of a natural salt wall, highlighting the presence of abruptly varying intrasalt structural styles. The structures identified and the inferred kinematics suggest that, given specific mechanical stratigraphy, density-driven overturn within salt diapirs can play a key role in their growth.
  • Journal article
    Prytulak J, Avanzinelli R, Koetsier G, Kreissig K, Beier C, Elliott Tet al., 2014,

    Melting versus contamination effects on <SUP>238</SUP>U-<SUP>230</SUP>Th-<SUP>226</SUP>Ra and <SUP>235</SUP>U-<SUP>231</SUP>Pa disequilibria in lavas from Sao Miguel, Azores

    , CHEMICAL GEOLOGY, Vol: 381, Pages: 94-109, ISSN: 0009-2541

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://www.imperial.ac.uk:80/respub/WEB-INF/jsp/search-t4-html.jsp Request URI: /respub/WEB-INF/jsp/search-t4-html.jsp Query String: id=833&limit=20&page=11&respub-action=search.html Current Millis: 1713989380237 Current Time: Wed Apr 24 21:09:40 BST 2024