114 results found
Jacobs CT, Goldin TJ, Collins GS, et al., 2015, An improved quantitative measure of the tendency for volcanic ash plumes to form in water: implications for the deposition of marine ash beds, JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH, Vol: 290, Pages: 114-124, ISSN: 0377-0273
Milbury C, Johnson BC, Melosh HJ, et al., 2015, Preimpact porosity controls the gravity signature of lunar craters, GEOPHYSICAL RESEARCH LETTERS, Vol: 42, Pages: 9711-9716, ISSN: 0094-8276
Miljkovic K, Wieczorek MA, Collins GS, et al., 2015, Excavation of the lunar mantle by basin-forming impact events on the Moon, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 409, Pages: 243-251, ISSN: 0012-821X
Muxworthy AR, Bland PA, Collins G, et al., 2015, MAGNETIC FABRICS IN ALLENDE: IMPLICATIONS FOR MAGNETIC REMANENCE ACQUISITION., 78th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, ISSN: 1086-9379
Ormoe J, Melero-Asensio I, Housen KR, et al., 2015, Scaling and reproducibility of craters produced at the Experimental Projectile Impact Chamber (EPIC), Centro de Astrobiologia, Spain, METEORITICS & PLANETARY SCIENCE, Vol: 50, Pages: 2067-2086, ISSN: 1086-9379
Potter RWK, Kring DA, Collins GS, 2015, Scaling of basin-sized impacts and the influence of target temperature, Special Paper of the Geological Society of America, Vol: 518, Pages: 99-113, ISSN: 0072-1077
© 2015 The Geological Society of America. All rights reserved. We produce a set of scaling laws for basin-sized impacts using data from a suite of lunar basin numerical models. The results demonstrate the importance of preimpact target temperature and thermal gradient, which are shown to greatly influence the modification phase of the impact cratering process. Impacts into targets with contrasting thermal properties also produce very different crustal and topographic profiles for impacts of the same energy. Thermal conditions do not, however, significantly influence the excavation stage of the cratering process; results demonstrate, as a consequence of gravity-dominated growth, that transient crater radii are generally within 5% of each other over a wide range of thermal gradients. Excava tion depth-to-diameter ratios for the basin models (~0.12) agree well with experimental, geological, and geophysical estimates, suggesting basins follow proportional scaling. This is further demonstrated by an agreement between the basin models and Piscaling laws based upon first principles and experimental data. The results of this work should also be applicable to basin-scale impacts on other silicate bodies, including the Hadean Earth.
Bland PA, Collins GS, Davison TM, et al., 2014, Pressure-temperature evolution of primordial solar system solids during impact-induced compaction, NATURE COMMUNICATIONS, Vol: 5, ISSN: 2041-1723
Bray VJ, Collins GS, Morgan JV, et al., 2014, Hydrocode simulation of Ganymede and Europa cratering trends - How thick is Europa's crust?, ICARUS, Vol: 231, Pages: 394-406, ISSN: 0019-1035
Collins GS, 2014, Numerical simulations of impact crater formation with dilatancy, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 119, Pages: 2600-2619, ISSN: 2169-9097
Davison TM, Ciesla FJ, Collins GS, et al., 2014, The effect of impact obliquity on shock heating in planetesimal collisions, METEORITICS & PLANETARY SCIENCE, Vol: 49, Pages: 2252-2265, ISSN: 1086-9379
Hill J, Collins GS, Avdis A, et al., 2014, How does multiscale modelling and inclusion of realistic palaeobathymetry affect numerical simulation of the Storegga Slide tsunami?, Ocean Modelling, Vol: 83, Pages: 11-25, ISSN: 1463-5003
The ∼8.15 ka Storegga submarine slide was a large (∼3000 km3), tsunamigenic slide off the coast of Norway. The resulting tsunami had run-up heights of around 10–20 m on the Norwegian coast, over 12 m in Shetland, 3–6 m on the Scottish mainland coast and reached as far as Greenland. Accurate numerical simulations of Storegga require high spatial resolution near the coasts, particularly near tsunami run-up observations, and also in the slide region. However, as the computational domain must span the whole of the Norwegian-Greenland sea, employing uniformly high spatial resolution is computationally prohibitive. To overcome this problem, we present a multiscale numerical model of the Storegga slide-generated tsunami where spatial resolution varies from 500 m to 50 km across the entire Norwegian-Greenland sea domain to optimally resolve the slide region, important coastlines and bathymetric changes. We compare results from our multiscale model to previous results using constant-resolution models and show that accounting for changes in bathymetry since 8.15 ka, neglected in previous numerical studies of the Storegga slide-tsunami, improves the agreement between the model and inferred run-up heights in specific locations, especially in the Shetlands, where maximum run-up height increased from 8 m (modern bathymetry) to 13 m (palaeobathymetry). By tracking the Storegga tsunami as far south as the southern North sea, we also found that wave heights were high enough to inundate Doggerland, an island in the southern North Sea prior to sea level rise over the last 8 ka.
Jacobs CT, Collins GS, Piggott MD, et al., 2014, Multiphase flow modelling of explosive volcanic eruptions using an adaptive unstructured mesh-based approach, Pages: 7406-7417
Explosive volcanic eruption events, in which large quantities of hot gas and ash are expelled high into the atmosphere, are one of the most powerful natural hazards. In order to gain a full understanding of the dangers these eruptions pose, their complex multiscale and multiphase nature must be captured to a high degree of accuracy. The application of numerical multiphase flow models often represents the only tenable way of achieving this, and permits the investigation of ash cloud evolution in domains many times larger than the laboratory-scale. However, even the most advanced models of eruption dynamics are restricted by the fixed mesh-based approaches that they generally employ. The research presented herein introduces a compressible multiphase flow model recently implemented within Fluidity, a combined finite element / control volume CFD code, for the study of explosive volcanic eruptions. Fluidity adopts an adaptive unstructured mesh-based approach to discretise the domain and focus numerical resolution only in areas important to the dynamics, while decreasing resolution where it is not needed as a simulation progresses. This allows the accurate but economical representation of the flow dynamics throughout time. The application of the model considers a 7 km × 7 km domain in which the violent eruption of hot gas and volcanic ash high into the atmosphere is simulated. It is shown by a convergence analysis that Fluidity offers the same solution accuracy for reduced computational cost using an adaptive unstructured mesh, compared to the same simulation performed with a fixed uniform mesh.
Milbury C, Johnson BC, Melosh HJ, et 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
Miljković K, Collins GS, Bland PA, 2014, Reply to comment on: “Supportive comment on: “Morphology and population of binary asteroid impact craters”, by K. Miljković, G.S. Collins, S. Mannick and P.A. Bland – An updated assessment”, Earth and Planetary Science Letters, Vol: 405, Pages: 285-286, ISSN: 0012-821X
In Miljković et al. (2013) we resolved the apparent contradiction that while 15% of the Near Earth Asteroid (impactor) population are binaries, only 2–4% of craters formed on Earth and Mars (target planet) are doublet craters. Using 3D hydrocode simulations to explore the physics of binary impacts, we showed that only 2% of binary asteroid impacts produced well-separated doublets, while the rest covered morphologies ranging from overlapping to elliptical or even circular. We then generated a complete classification dataset to aid in the identification of the (sometimes subtle) morphological characteristics consistent with a binary asteroid impact. We thank Schmieder et al. (2013) for providing additional detailed geochronological constraints which indicate that our lower bound of 2% doublet craters on Earth may in fact be ≤1.5%.
Neal WD, Appleby-Thomas GJ, Collins GS, 2014, Meso-scopic deformation in brittle granular materials, 18TH APS-SCCM AND 24TH AIRAPT, PTS 1-19, Vol: 500, ISSN: 1742-6588
Bland PA, Collins GS, Dyl KA, et al., 2013, IMPACT-INDUCED COMPACTION OF PRIMORDIAL MATERIALS AND THE EFFECT ON THE CHONDRITE RECORD., 76th Annual Meeting of the Meteoritical-Society, Publisher: WILEY-BLACKWELL, Pages: A63-A63, ISSN: 1086-9379
Ciesla FJ, Davison TM, Collins GS, et al., 2013, Thermal consequences of impacts in the early solar system, METEORITICS & PLANETARY SCIENCE, Vol: 48, Pages: 2559-2576, ISSN: 1086-9379
Davison TM, O'Brien DP, Ciesla FJ, et al., 2013, The early impact histories of meteorite parent bodies, METEORITICS & PLANETARY SCIENCE, Vol: 48, Pages: 1894-1918, ISSN: 1086-9379
Elbeshausen D, Wuennemann K, Collins GS, 2013, The transition from circular to elliptical impact craters, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 118, Pages: 2295-2309, ISSN: 2169-9097
Jacobs 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: 647-665, ISSN: 0956-540X
Miljkovic K, Collins GS, Mannick S, et al., 2013, Morphology and population of binary asteroid impact craters, EARTH AND PLANETARY SCIENCE LETTERS, Vol: 363, Pages: 121-132, ISSN: 0012-821X
Miljkovic K, Wieczorek MA, Collins GS, et al., 2013, Asymmetric Distribution of Lunar Impact Basins Caused by Variations in Target Properties, SCIENCE, Vol: 342, Pages: 724-726, ISSN: 0036-8075
Oishi Y, Piggott MD, Maeda T, et al., 2013, Three-dimensional tsunami propagation simulations using an unstructured mesh finite element model, JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, Vol: 118, Pages: 2998-3018, ISSN: 2169-9313
Potter 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: 1086-9379
Potter RWK, Kring DA, Collins GS, 2013, Quantifying the attenuation of structural uplift beneath large lunar craters, GEOPHYSICAL RESEARCH LETTERS, Vol: 40, Pages: 5615-5620, ISSN: 0094-8276
Potter 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, Vol: 118, Pages: 963-979, ISSN: 2169-9097
Bray 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: 115-129, ISSN: 0019-1035
Collins GS, 2012, Moonstruck Magnetism, SCIENCE, Vol: 335, Pages: 1176-1177, ISSN: 0036-8075
Collins GS, Melosh HJ, Osinski GR, 2012, The Impact-Cratering Process, ELEMENTS, Vol: 8, Pages: 25-30, ISSN: 1811-5209
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