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Journal articleSaunders JH, Jackson MD, Pain CC, et al., 2012,
Streaming potentials in hydrocarbon reservoir conditions
, Geophysics, Vol: 77, Pages: E77-E90 -
Journal articleHill J, Piggott MD, Ham DA, et al., 2012,
On the performance of a generic length scale turbulence model within an adaptive finite element ocean model
, Ocean Modelling, Vol: 56, Pages: 1-15Research into the use of unstructured mesh methods for ocean modelling has been growing steadily in the last few years. One advantage of using unstructured meshes is that one can concentrate resolution where it is needed. In addition, dynamic adaptive mesh optimisation (DAMO) strategies allow resolution to be concentrated when this is required. Despite the advantage that DAMO gives in terms of improving the spatial resolution where and when required, small-scale turbulence in the oceans still requires parameterisation. A two-equation, generic length scale (GLS) turbulence model (one equation for turbulent kinetic energy and another for a generic turbulence length-scale quantity) adds this parameterisation and can be used in conjunction with adaptive mesh techniques. In this paper, an implementation of the GLS turbulence parameterisation is detailed in a non-hydrostatic, finite-element, unstructured mesh ocean model, Fluidity-ICOM. The implementation is validated by comparing to both a laboratory-scale experiment and real-world observations, on both fixed and adaptive meshes. The model performs well, matching laboratory and observed data, with resolution being adjusted as necessary by DAMO. Flexibility in the prognostic fields used to construct the error metric used in DAMO is required to ensure best performance. Moreover, the adaptive mesh models perform as well as fixed mesh models in terms of root mean square error to observation or theoretical mixed layer depths, but uses fewer elements and hence has a reduced computational cost.
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Journal articleBray VJ, Schenk PM, Melosh HJ, et al., 2012,
Ganymede crater dimensions – Implications for central peak and central pit formation and development
, Icarus, Vol: 217, Pages: 115-129The morphology of impact craters on the icy Galilean satellites differs from craters on rocky bodies. Thedifferences are thought due to the relative weakness of ice and the possible presence of sub-surface waterlayers. Digital elevation models constructed from Galileo images were used to measure a range of dimensionsof craters on the dark and bright terrains of Ganymede. Measurements were made from multipleprofiles across each crater, so that natural variation in crater dimensions could be assessed and averagedscaling trends constructed. The additional depth, slope and volume information reported in this work hasenabled study of central peak formation and development, and allowed a quantitative assessment of thevarious theories for central pit formation. We note a possible difference in the size-morphology progressionbetween small craters on icy and silicate bodies, where central peaks occur in small craters beforethere is any slumping of the crater rim, which is the opposite to the observed sequence on the Moon. Conversely,our crater dimension analyses suggest that the size-morphology progression of large lunar cratersfrom central peak to peak-ring is mirrored on Ganymede, but that the peak-ring is subsequentlymodified to a central pit morphology. Pit formation may occur via the collapse of surface material intoa void left by the gradual release of impact-induced volatiles or the drainage of impact melt intosub-crater fractures.
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Journal articlevan Reeuwijk M, Sookhak Lari K, 2012,
Asymptotic Solutions for turbulent mass transfer at high Schmidt number
, PROC ROY SOC A -
Journal articleStafford PJ, 2012,
Evaluation of structural performance in the immediate aftermath of an earthquake: a case study of the 2011 Christchurch earthquake
, International Journal of Forensic Engineering, Vol: 1, Pages: 58-77 -
Journal articleYoung NE, Briner JP, Axford Y, et al., 2011,
Response of a marine-terminating Greenland outlet glacier to abrupt cooling 8200 and 9300 years ago
, Geophysical Research Letters, Vol: 38, ISSN: 0094-8276Long-term records of Greenland outlet-glacier change extending beyond the satellite era can inform future predictions of Greenland Ice Sheet behavior. Of particular relevance is elucidating the Greenland Ice Sheet's response to decadal-and centennial-scale climate change. Here, we reconstruct the early Holocene history of Jakobshavn Isbr, Greenland's largest outlet glacier, using <sup>10</sup>Be surface exposure ages and <sup>14</sup>C-dated lake sediments. Our chronology of ice-margin change demonstrates that Jakobshavn Isbr advanced to deposit moraines in response to abrupt cooling recorded in central Greenland ice cores ca. 8,200 and 9,300 years ago. While the rapid, dynamically aided retreat of many Greenland outlet glaciers in response to warming is well documented, these results indicate that marine-terminating outlet glaciers are also able to respond quickly to cooling. We suggest that short lag times of high ice flux margins enable a greater magnitude response of marine-terminating outlets to abrupt climate change compared to their land-terminating counterparts. Copyright 2011 by the American Geophysical Union.
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Book chapterJackson CAL, Kane KE, 2011,
Application of 3D seismic data to understanding the structure and stratigraphy of sedimentary basins
, Tectonics of Sedimentary Basins: Recent Advances, Editors: Busby, Pérez, Publisher: Wiley-Blackwell, Pages: 95-110, ISBN: 9781405194655Although 2D seismic data are able to provide regional insights into the broad form and fill of sedimentary basins, their limited spatial resolution restricts the detailed analysis of geological features. Improvements in 3D seismic acquisition and processing techniques have resulted in large tracts of sedimentary basins being covered by high-quality surveys. The development of sophisticated software, and low-cost, high-powered workstations, allows the interpretation of these data in unprecedented detail. This chapter focuses on some of the key interpretation techniques available to the seismic interpreter, and will demonstrate how these can be used to gain an understanding of the structure and fill of sedimentary basins at a range of scales. The benefits of analysing structure and stratigraphic thickness maps are considered, as these are important for defining basin structure, and for highlighting the temporal and spatial variability of syn-depositional accommodation, tectonics and erosion. The use of ‘seismic attributes analysis’ to highlight geological features is discussed. These attributes include, amongst others, grid- and volume-based geometric attributes, and grid and volume-derived, amplitude-based attributes. Although seismic attribute analysis is a powerful tool in basin analysis, the answer to a subsurface geological problem does not lie within the workstation or the attributes that can be generated. The workstation is only a tool. The key elements involved in the successful application of seismic data to basin analysis are: (i) a knowledge of the available interpretation tools, (ii) an appreciation of the physical basis of the attributes being used, (iii) an understanding of the impact of data and interpretation quality on the derived attributes and (iv) a thoughtful geological interpretation of geophysical data. With continued improvements in spatial coverage and resolution, seismic reflection datasets have the potential to be as powerful a t
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Journal articleSouthern J, Gorman GJ, Piggott MD, et al., 2011,
Parallel anisotropic mesh adaptivity with dynamic load balancing for cardiac electrophysiology
, Journal of Computational Science, Vol: 3, Pages: 8-16 -
Journal articleStyles E, Goes S, van Keken PE, et al., 2011,
Synthetic images of dynamically predicted plumes and comparison with a global tomographic model
, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 311, Pages: 351-363, ISSN: 0012-821X- Author Web Link
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- Citations: 25
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Journal articleRood DH, Burbank DW, Herman SW, et al., 2011,
Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada
, Tectonics, Vol: 30, ISSN: 0278-7407We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (∼9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± δR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (∼12-20 Ma), 42 ± 11° since Late Miocene (∼8-9 Ma), and 14 ± 10° since Pliocene (∼3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma<sup>-1</sup> (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (∼9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates. Copyright 2011 by the American Geophysical Union.
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Journal articleHwang YK, Ritsema J, van Keken PE, et al., 2011,
Wavefront healing renders deep plumes seismically invisible
, GEOPHYSICAL JOURNAL INTERNATIONAL, Vol: 187, Pages: 273-277, ISSN: 0956-540X- Author Web Link
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- Citations: 33
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Journal articleDavison TM, Collins GS, Elbeshausen D, et al., 2011,
Numerical modeling of oblique hypervelocity impacts on strong ductile targets
, METEORITICS & PLANETARY SCIENCE, Vol: 46, Pages: 1510-1524, ISSN: 1086-9379- Author Web Link
- Open Access Link
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- Citations: 61
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Journal articleCollins GS, Elbeshausen D, Davison TM, et al., 2011,
The size-frequency distribution of elliptical impact craters
, Earth and Planetary Science Letters, Vol: 310, Pages: 1-8, ISSN: 0012-821X -
Conference paperJohnson HD, Alqahtani F, Jackson CAL, et al., 2011,
Fluvial reservoir analogues in the Malay Basin: analysis of shallow 3D seismic data of Pleistocene rivers on the Sunda Shelf.
, Seismic Imaging of Depositional and Geomorphic Systems: 30th Annual GCSSEPM Foundation Annual Bob F. Perkins Research Conference Proceedings, Publisher: GCSSEPM Proceedings, Pages: 328-329This study focuses on the analysis of Pliocene fluvial depositional systems based on the shallow part (seabed to about 500 m) of a large (>10,000 km2), mega-merge 3D seismic dataset from the Malay Basin, Southeast Asia. The results of a detailed 3D seismic facies analysis, locally calibrated with high-resolution site survey data, will be presented. The Pliocene interval is up to approximately 500 m thick and comprises a range of seismic facies, which reflect changes in fluvial channel style and gross stratigraphic architecture. The succession has been divided into five stratigraphic units, bounded by basin-wide stratal surfaces. The expression of these fluvial systems will be illustrated in seismic sections, stratal and proportional slices, and through various 3D volume extraction displays. This will include the youngest channel complex, which forms part of a major incised valley (approximately 18 km wide and up to 90 m deep), which formed an axial drainage system along the length of the Malay Basin during the latest Pleistocene, when the whole Sunda Shelf was exposed. In other intervals, the coastal plain is characterised by a range of unconfined high- and low-sinuosity fluvial channel systems. Planform geometries and other dimensions have been documented using GIS methods in order to develop a quantitative database of the Sunda Shelf fluvial systems.These data and other observation from the Pliocene fluvial systems are being used to determine reservoir body dimensions, geometries and estimates of connectivity that will aid the interpretation of similar, fluvial reservoirs in the deeper prospective Miocene interval.
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Conference paperPotts DM, Zdravkovic L, 2011,
Application of partial factors of safety in numerical analysis of bearing capacity
, Pages: 775-781One of the issues that arise when using numerical analysis in accordance with Eurocode 7 is how to account for partial factors of safety on material strength. Namely, Eurocode 7 implies that strengths to be used in an analysis should be based on a design value, but reduced by partial factors. This can be done in two ways, but Eurocode 7 gives no guidance as to which one is more appropriate. This paper examines the application of partial factors of safety in a bearing capacity problem. Finite element analyses are performed using both a simple Tresca and a more advanced Modified Cam Clay models to represent soil behaviour, and both approaches for the application of partial factors of safety.
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Conference paperAnh-Minh N, Nishimura S, Takahashi A, et al., 2011,
On the control systems and instrumentation required to investigate the anisotropy of stiff clays and mudrocks through Hollow Cylinder Tests
, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 287-294 -
Conference paperRimoy SP, Jardine RJ, 2011,
Strain accumulation in a silica sand due to creep after normal compression, and during sustained low-level cyclic loading
, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 463-470 -
Conference paperShen CH, O'Sullivan C, Jardine RJ, 2011,
A micromechanical investigation of drained simple shear tests Deformation Characteristics of Geomaterials
, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 314-321 -
Conference paperAltuhafi F, Jardine RJ, 2011,
Effect of particle breakage and strain path reversal on the properties of sands located near to driven piles
, Seoul, Korea, 5th International Symposium on Deformation Characteristics of Geomaterials, Publisher: Hanrimwon, Pages: 386-395 -
Conference paperBrosse A, Hosseini Kamal R, Jardine RJ, et al., 2011,
Measuring the static and dynamic small strain stiffness of UK mudrocks
, 15th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE), Publisher: Millpress, Pages: 137-142
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