The “Boscobel Landslip” of October 1st, 1901—the largest historic landslide in Barbados,West Indies     

David Cruden  Hans G. Machel  John Knox  Richard Goddard 《Landslides》2014,11(4):673-684

Barbados is a small Caribbean island located on the crest of an accretionary prism about 125 km east of the Lesser Antilles volcanic island arc. The oldest strata, Eocene sandstones and shales, are overlain by Oligocene–Miocene chalks and marls, in turn overlain by Pleistocene reef and lagoonal limestones that cover about 85 % of the island. The Eocene sediments, which crop out in the Scotland District of Barbados, are prone to soil creep and landslides covering tens to hundreds of hectares. The largest historic landslide, the “Boscobel Landslip,” occurred on 01 October 1901. We used nineteenth-century and more modern topographic and geologic maps, air photographs, and various archival and petrophysical data, to supplement reconnaissance of the landslide in the field. We identified about ten million cubic meters of the displaced material of the landslide, as well as the meteorological and geological conditions that contributed to the Boscobel Landslip. Similar landslides would pose a presently unquantified hazard to inhabitation and future development in the Scotland District.  相似文献   

The 2dF galaxy redshift survey: clustering properties of radio galaxies     

Manuela Magliocchetti  Steve J. Maddox  Ed Hawkins  John A. Peacock  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Shaun Cole  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto de Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Carole A. Jackson  Bryn Jones  Ofer Lahav  Ian Lewis  Stuart Lumsden  Peder Norberg  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,350(4):1485-1494

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Automated design of gravity-assist trajectories to Mars and the outer planets   总被引：1，自引：0，他引：1  

James M. Longuski  Steve N. Williams 《Celestial Mechanics and Dynamical Astronomy》1991,52(3):207-220

In this paper, a new approach to planetary mission design is described which automates the search for gravity-assist trajectories. This method finds all conic solutions given a range of launch dates, a range of launch energies and a set of target planets. The new design tool is applied to the problems of finding multiple encounter trajectories to the outer planets and Venus gravity-assist trajectories to Mars. The last four-planet grand tour opportunity (until the year 2153) is identified. It requires an Earth launch in 1996 and encounters Jupiter, Uranus, Neptune, and Pluto. Venus gravity-assist trajectories to Mars for the 30 year period 1995–2024 are examined. It is shown that in many cases these trajectories require less launch energy to reach Mars than direct ballistic trajectories.Assistant Professor, School of Aeronautics and AstronauticsGraduate Student, School of Aeronautics and Astronautics  相似文献   

Ion winds in Saturn's southern auroral/polar region     

Tom S Stallard  Steve Miller  Laurence M Trafton  Robert D Joseph 《Icarus》2004,167(1):204-211

We present profiles of the line-of-sight (l.o.s.) ionospheric wind velocities in the southern auroral/polar region of Saturn. Our velocities are derived from the measurement of Doppler shifting of the H₃⁺ν₂Q(1,0⁻) line at 3.953 microns. The data for this study were obtained using the facility high-resolution spectrometer CSHELL on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii, during the night of February 6, 2003 (UT). The l.o.s. velocity profiles finally derived are consistent with an extended region of the upper atmosphere sub-corotating with the planet: the ion velocities in the inertial reference are only 1/3 of those expected for full planetary corotation. We discuss the results in the light of recent proposals for the kronian magnetosphere, and suggest that, in this region, Saturn's ion winds may be under solar wind control.  相似文献   

The 2dF Galaxy Redshift Survey: the b_J-band galaxy luminosity function and survey selection function     

Peder Norberg  Shaun Cole  Carlton M. Baugh  Carlos S. Frenk  Ivan Baldry  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Matthew Colless  Chris Collins  Warrick Couch  Nicholas J. G. Cross  Gavin Dalton  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Karl Glazebrook  Carole Jackson  Ofer Lahav  Ian Lewis  Stuart Lumsden  Steve Maddox  Darren Madgwick  John A. Peacock  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,336(3):907-931

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The 2dF Galaxy Redshift Survey: luminosity dependence of galaxy clustering     

Peder Norberg  Carlton M. Baugh  Ed Hawkins  Steve Maddox  John A. Peacock  Shaun Cole  Carlos S. Frenk  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Karl Glazebrook  Carole Jackson  Ofer Lahav  Ian Lewis  Stuart Lumsden  Darren Madgwick  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2001,328(1):64-70

We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift surveys used to address this issue. We measure the projected two-point correlation function of galaxies in a series of volume-limited samples. The projected correlation function is free from any distortion of the clustering pattern induced by peculiar motions and is well described by a power law in pair separation over the range     . The clustering of     galaxies in real space is well-fitted by a correlation length     and power-law slope     . The clustering amplitude increases slowly with absolute magnitude for galaxies fainter than M *, but rises more strongly at higher luminosities. At low luminosities, our results agree with measurements from the Southern Sky Redshift Survey 2 by Benoist et al. However, we find a weaker dependence of clustering strength on luminosity at the highest luminosities. The correlation function amplitude increases by a factor of 4.0 between     and −22.5, and the most luminous galaxies are 3.0 times more strongly clustered than L * galaxies. The power-law slope of the correlation function shows remarkably little variation for samples spanning a factor of 20 in luminosity. Our measurements are in very good agreement with the predictions of the hierarchical galaxy formation models of Benson et al.  相似文献   

Environmental changes on Yugorski Peninsula, Kara Sea, Russia, during the last 12,800 radiocarbon years     

Andrei A. Andreev  William F. Manley   lafur Inglfsson  Steve L. Forman 《Global and Planetary Change》2001,31(1-4)

New pollen and radiocarbon data from an 8.6-m coastal section, Cape Shpindler (69°43′N; 62°48′E), Yugorski Peninsula, document the latest Pleistocene and Holocene environmental history of this low Arctic region. Twelve AMS ¹⁴C dates indicate that the deposits accumulated since about 13,000 until 2000 radiocarbon years BP. A thermokarst lake formed ca. 13,000–12,800 years BP, when scarce arctic tundra vegetation dominated the area. By 12,500 years BP, a shallow lake existed at the site, and Arctic tundra with Poaceae, Cyperaceae, Salix, Saxifraga, and Artemisia dominated nearby vegetation. Climate was colder than today. Betula nana became dominant during the Early Preboreal period about 9500 years BP, responding to a warm event, which was one of the warmest during the Holocene. Decline in B. nana and Salix after 9500 years BP reflects a brief event of Preboreal cooling. A subsequent increase in Betula and Alnus fruticosa pollen percentages reflects amelioration of environmental conditions at the end of Preboreal period (ca. 9300 years BP). A decline in arboreal taxa later, with a dramatic increase in herb taxa, reflects a short cold event at about 9200 years BP. The pollen data reflect a northward movement of tree birch, peaking at the middle Boreal period, around 8500 years BP. Open Betula forest existed on the Kara Sea coast of the Yugorski Peninsula during the Atlantic period (8000–4500 years BP), indicating that climate was significantly warmer than today. Deteriorating climate around the Atlantic–Subboreal boundary (ca. 4500 years BP) is recorded by a decline in Betula percentages. Sedimentation slowed at the site, and processes of denudation and/or soil formation started at the beginning of the Subatlantic period, when vegetation cover on Yugorski Peninsula shifted to near-modern assemblages.  相似文献   

The 2dF Galaxy Redshift Survey: the environmental dependence of galaxy star formation rates near clusters     

Ian Lewis  Michael Balogh  Roberto De Propris  Warrick Couch  Richard Bower  Alison Offer  Joss Bland-Hawthorn  Ivan K. Baldry  Carlton Baugh  Terry Bridges  Russell Cannon  Shaun Cole  Matthew Colless  Chris Collins  Nicholas Cross  Gavin Dalton  Simon P. Driver  George Efstathiou  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Edward Hawkins  Carole Jackson  Ofer Lahav  Stuart Lumsden  Steve Maddox  Darren Madgwick  Peder Norberg  John A. Peacock  Will Percival  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,334(3):673-683

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Galaxy groups in the Two-degree Field Galaxy Redshift Survey: the luminous content of the groups     

V. R. Eke  Carlos S. Frenk  Carlton M. Baugh  Shaun Cole  Peder Norberg  John A. Peacock  Ivan K. Baldry  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto de Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Karl Glazebrook  Carole A. Jackson  Ofer Lahav  Ian Lewis  Stuart Lumsden  Steve J. Maddox  Darren Madgwick  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,355(3):769-784

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Decadal‐Scale Changes of the Ödenwinkelkees,Central Austria,Suggest Increasing Control of Topography and Evolution Towards Steady State          下载免费PDF全文

Jonathan L. Carrivick  Katie Berry  Martin Geilhausen  William H.M. James  Christopher Williams  Lee E. Brown  David M. Rippin  Steve J. Carver 《Geografiska Annaler: Series A, Physical Geography》2015,97(3):543-562

Small mountain glaciers have short mass balance response times to climate change and are consequently very important for short‐term contributions to sea level. However, a distinct research and knowledge gap exists between (1) wider regional studies that produce overview patterns and trends in glacier changes, and (2) in situ local scale studies that emphasise spatial heterogeneity and complexity in glacier responses to climate. This study of a small glacier in central Austria presents a spatiotemporally detailed analysis of changes in glacier geometry and changes in glaciological behaviour. It integrates geomorphological surveys, historical maps, aerial photographs, airborne LiDAR data, ground‐based differential global positioning surveys and Ground Penetrating Radar surveys to produce three‐dimensional glacier geometry at 13 time increments spanning from 1850 to 2013. Glacier length, area and volume parameters all generally showed reductions with time. The glacier equilibrium line altitude increased by 90 m between 1850 and 2008. Calculations of the mean bed shear stress rapidly approaching less than 100 kPA, of the volume–area ratio fast approaching 1.458, and comparison of the geometric reconstructions with a 1D theoretical model could together be interpreted to suggest evolution of the glacier geometry towards steady state. If the present linear trend in declining ice volume continues, then the Ödenwinkelkees will disappear by the year 2040, but we conceptualise that non‐linear effects of bed overdeepenings on ice dynamics, of supraglacial debris cover on the surface energy balance, and of local topographically driven controls, namely wind‐redistributed snow deposition, avalanching and solar shading, will become proportionally more important factors in the glacier net balance.  相似文献