Displacement-length scaling relations for faults on the terrestrial planets     

Richard A. Schultz  Chris H. Okubo  Scott J. Wilkins   《Journal of Structural Geology》2006,28(12):2182

Displacement-length (D/L)scaling relations for normal and thrust faults from Mars, and thrust faults from Mercury, for which sufficiently accurate measurements are available, are consistently smaller than terrestrial D/L ratios by a factor of about 5, regardless of fault type (i.e. normal or thrust). We demonstrate that D/L ratios for faults scale, to first order, with planetary gravity. In particular, confining pressure modulates: (1) the magnitude of shear driving stress on the fault; (2) the shear yield strength of near-tip rock; and (3) the Young's (or shear) modulus of crustal rock. In general, all three factors decrease with gravity for the same rock type and pore-pressure state (e.g. wet conditions). Faults on planets with lower surface gravities, such as Mars and Mercury, demonstrate systematically smaller D/L ratios than faults on larger planets, such as Earth. Smaller D/L ratios of faults on Venus and the Moon are predicted by this approach, and we infer still smaller values of D/L ratio for faults on icy satellites in the outer solar system. Collection of additional displacement-length and down-dip height data from terrestrial normal, strike-slip, and thrust faults, located within fold-and-thrust belts, plate margins, and continental interiors, is required to evaluate the influence of fault shape and progressive deformation on the scaling relations for faults from Earth and elsewhere.  相似文献   

Erratum to: “Normal fault growth in layered rocks at Split Mountain, Utah: influence of mechanical stratigraphy on dip linkage, fault restriction and fault scaling”: [Journal of Structural Geology 24 (2002) 1413–1429]     

Scott J. Wilkins  Michael R. Gross 《Journal of Structural Geology》2002,24(12):1413

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Timing and Extent of Late Quaternary Paleolakes in the Trans-Pecos Closed Basin, West Texas and South-Central New Mexico     

David E. Wilkins  Donald R. Currey 《Quaternary Research》1997,47(3):306-315

The Trans-Pecos Closed Basin is a hydrographically closed region covering 20,000 km²centered on Salt Basin, 160 km east of El Paso, Texas. Geomorphic and limnetic evidence have been used to identify four major highstands for Lake King during the last glacial maximum (LGM). Additional geomorphic features from a second, recently identified, paleolake, Lake Sacramento, have been found in the Beargrass subbasin, a nested subbasin approximately 75 km northwest of Salt Basin. Radiocarbon ages of the organic material in Lake King sediments date four abrupt climate changes and rapid lacustrine transgressions during the LGM with a quasi-periodicity of 2000 yr. Geomorphic evidence in the Beargrass subbasin identifies lake cycles contemporaneous with those in Lake King. The dates for these transgressions correlate with the dates of freshening events identified by researchers in paleolake basins elsewhere in New Mexico. The quasi-periodicity of the events approximates that of Dansgaard–Oeschger events identified from Greenland ice cores. The contemporaneity of the Trans-Pecos transgressions with transgressive events in other basins in the region suggests that paleolakes in the region were in phase with respect to abrupt climate changes during the latter stages of the LGM.  相似文献   

Mechanical Study of Shear Failure of Vertical Goaf Drainage Hole     

Khanal  Manoj  Adhikary  Deepak  Balusu  Rao  Wilkins  Andy  Belle  Bharath 《Geotechnical and Geological Engineering》2022,40(4):1899-1920

Geotechnical and Geological Engineering - Most of the published research on goaf-hole failures are performed using 2D numerical analyses. However, 2D analyses of the goaf-hole failure mechanism,...  相似文献   

Declining diversity of egg-associated bacteria during development of naturally spawned whitefish embryos (Coregonus spp.)     

Laetitia G. E. Wilkins  Aude Rogivue  Luca Fumagalli  Claus Wedekind 《Aquatic Sciences - Research Across Boundaries》2015,77(3):481-497

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Spatial Aspects of Restrictions on Registered Sex Offenders          下载免费PDF全文

Mark Leipnik  Xinyue Ye  Jose Serna  James Strong  Christopher Wilkins  Ling Wu 《Geographical review》2016,106(2):312-330

Restrictions in the USA on registered sex offenders (RSOs) are examined from the spatial aspects. The long history of various restrictions imposed by government, particularly local ones, is covered in the introduction. Spatial aspects, such as delineation of zones from which certain activities or certain people are excluded is the focus. Then the nature of restrictions on RSOs is considered at the state, county and municipal level. Typical of restrictions are that RSOs are prohibited from moving into residence within a prescribed distance of certain features in a community. The distances are typically 1,000 feet but are quite variable. Typical proscribed venues are schools, parks and day care centers, but there can be many others such as bus stops. Spatial aspects of these restrictions, such as how offender locations are geocoded and represented and how proscribed venues are delineated is analyzed. Specific details and theoretical concerns related to the many problematic issues with RSO restrictions is presented. In particular questions of their constitutionality and efficacy are raised. The paper concludes with a discussion of the implications of RSO restrictions for the discipline of geography in general and for the evolution of increasingly precise methods of spatial analysis in particular.  相似文献   

Polymorphism of whole Blood Proteins in the Cod (Gadus morhua L.)     

Wilkins  N. P. 《ICES Journal of Marine Science》1967,31(1):77-88

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A theory for the shear strength of rockfill   总被引：1，自引：0，他引：1  

J. K. Wilkins 《Rock Mechanics and Rock Engineering》1970,2(4):205-222

SummaryA Theory for the Shear Strength of Rockfill Existing knowledge of the meaning of the shear strength of rock fill, and of how and why it varies is inadequate.Shear strength is shown to be controlled by the basic angle of friction of rock on rock ( _u ), the voids ratio (e) and the particle breakage (B) and to be dependent on the ratio of major to minor principal stresses.Using statistical methods combined with some simple assumptions based on experimental work formulas are derived for the shear strength of rock fill.Theoretical results are compared with the results of laboratory triaxial tests.

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Zusammenfassung Eine Theorie für die Scherfestigkeit von Gröbstkornschüttungen (Steinbrockenschüttungen). Das vorhandene Wissen vom Wesen der Scherfestigkeit von Gröbstkornschüttungen sowie davon, wie und warum sie verschieden groß ist, ist unzulänglich.Es wird gezeigt, daß die Scherfestigkeit durch den entscheidenden Reibungswinkel von Gestein auf Gestein ( _u ), den Hohlraum-Quotienten (e) und den Bruch von Teilchen (B) bestimmt wird, und daß sie von dem Quotienten aus größter und kleinster Hauptnormalspannung abhängt. Bei der Anwendung statistischer Methoden, welche mit einigen einfachen, auf Versuchen beruhenden Annahmen kombiniert werden, können Formeln für die Scherfestigkeit von Gröbstkornschüttungen abgeleitet werden. Theoretische Ergebnisse werden mit den Ergebnissen von Triaxialversuchen im Labor verglichen.

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Résumé Une théorie pour la résistance au cisaillement des enrochements. Les connaissances actuelles sur la signification de la résistance au cisaillement des enrochements, et sur le pourquoi et le comment de ses variations sont insuffisantes.On montre que la résistance au cisaillement dépend de l'angle de frottement élémentaire rocher sur rocher ( _u ), de l'indice des vides (e) et de la rupture des blocs (B), et qu'elle varie avec le rapport des contraintes principales extrêmes.Grâce à des méthodes statistiques et à quelques hypothèses simples basées sur un travail expérimental, on obtient des formules donnant la résistance au cisaillement des enrochements.Les résultats théoriques sont comparés avec les résultats d'essais triaxiaux au laboratoire.

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With 8 Figures  相似文献   

Composition,stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle,CO     

K.M. Campbell  J.A. Davis  J. Bargar  D. Giammar  R. Bernier-Latmani  R. Kukkadapu  K.H. Williams  H. Veramani  K.-U. Ulrich  J. Stubbs  S. Yabusaki  L. Figueroa  E. Lesher  M.J. Wilkins  A. Peacock  P.E. Long 《Applied Geochemistry》2011

Reductive biostimulation is currently being explored as a possible remediation strategy for U-contaminated groundwater, and is being investigated at a field site in Rifle, CO, USA. The long-term stability of the resulting U(IV) phases is a key component of the overall performance of the remediation approach and depends upon a variety of factors, including rate and mechanism of reduction, mineral associations in the subsurface, and propensity for oxidation. To address these factors, several approaches were used to evaluate the redox sensitivity of U: (1) measurement of the rate of oxidative dissolution of biogenic uraninite (UO_2(s)) deployed in groundwater at Rifle, (2) characterization of a zone of natural bioreduction exhibiting relevant reduced mineral phases, and (3) laboratory studies of the oxidative capacity of Fe(III) and reductive capacity of Fe(II) with regard to U(IV) and U(VI), respectively.  相似文献   

The evolution of stellar mass and the implied star formation history     

Stephen M. Wilkins  Neil Trentham  Andrew M. Hopkins 《Monthly notices of the Royal Astronomical Society》2008,385(2):687-694

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