Skip to main content
U.S. flag

An official website of the United States government

Publications

Filter Total Items: 7495

Assessment of environments for Mars Science Laboratory entry, descent, and surface operations Assessment of environments for Mars Science Laboratory entry, descent, and surface operations

The Mars Science Laboratory mission aims to land a car-sized rover on Mars' surface and operate it for at least one Mars year in order to assess whether its field area was ever capable of supporting microbial life. Here we describe the approach used to identify, characterize, and assess environmental risks to the landing and rover surface operations. Novel entry, descent, and landing...
Authors
Ashwin R. Vasavada, Allen Chen, Jeffrey R. Barnes, P. Daniel Burkhart, Bruce A. Cantor, Alicia M. Dwyer-Cianciolo, Robini L. Fergason, David P. Hinson, Hilary L. Justh, David M. Kass, Stephen R. Lewis, Michael A. Mischna, James R. Murphy, Scot C.R. Rafkin, Daniel Tyler, Paul G. Withers

Geometric derivations of minimal sets of sufficient multiview constraints Geometric derivations of minimal sets of sufficient multiview constraints

Geometric interpretations of four of the most common determinant formulations of multiview constraints are given, showing that they all enforce the same geometry and that all of the forms commonly in use in the machine vision community are a subset of a more general form. Generalising the work of Yi Ma yields a new general 2 x 2 determinant trilinear and 3 x 3 determinant quadlinear...
Authors
Orrin H. Thomas, Edward R. Oshel

Designs and test results for three new rotational sensors Designs and test results for three new rotational sensors

We discuss the designs and testing of three rotational seismometer prototypes developed at the Institute of Geophysics, Academy of Sciences (Prague, Czech Republic). Two of these designs consist of a liquid-filled toroidal tube with the liquid as the proof mass and providing damping; we tested the piezoelectric and pressure transduction versions of this torus. The third design is a wheel...
Authors
P. Jedlicka, J.T. Kozak, J.R. Evans, C. R. Hutt

Effects of soil-engineering properties on the failure mode of shallow landslides Effects of soil-engineering properties on the failure mode of shallow landslides

Some landslides mobilize into flows, while others slide and deposit material immediately down slope. An index based on initial dry density and fine-grained content of soil predicted failure mode of 96 landslide initiation sites in Oregon and Colorado with 79% accuracy. These material properties can be used to identify potential sources for debris flows and for slides. Field data suggest...
Authors
Jonathan Peter McKenna, Paul Michael Santi, Xavier Amblard, Jacquelyn Negri

Changes in permeability caused by transient stresses: field observations, experiments, and mechanisms Changes in permeability caused by transient stresses: field observations, experiments, and mechanisms

Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10–6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period...
Authors
Michael Manga, Igor Beresnev, Emily E. Brodsky, Jean E. Elkhoury, Derek Elsworth, Steve E. Ingebritsen, David C. Mays, Chi-Yuen Wang

Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment

Debris flows can dramatically increase their volume, and hence their destructive potential, by entraining sediment. Yet quantitative constraints on rates and mechanics of sediment entrainment by debris flows are limited. Using an in situ sensor network in the headwaters of a natural catchment we measured flow and bed properties during six erosive debris-flow events. Despite similar flow...
Authors
S.W. McCoy, Jason W. Kean, Jeffrey A. Coe, G.E. Tucker, Dennis M. Staley, T.A. Wasklewicz

Helping safeguard Veterans Affairs' hospital buildings by advanced earthquake monitoring Helping safeguard Veterans Affairs' hospital buildings by advanced earthquake monitoring

In collaboration with the U.S. Department of Veterans Affairs (VA), the National Strong Motion Project of the U.S. Geological Survey has recently installed sophisticated seismic systems that will monitor the structural integrity of hospital buildings during earthquake shaking. The new systems have been installed at more than 20 VA medical campuses across the country. These monitoring...
Authors
Erol Kalkan, Krishna Banga, Hasan S. Ulusoy, Jon Peter B. Fletcher, William S. Leith, James L. Blair

Turbidite event history—Methods and implications for Holocene paleoseismicity of the Cascadia subduction zone Turbidite event history—Methods and implications for Holocene paleoseismicity of the Cascadia subduction zone

Turbidite systems along the continental margin of Cascadia Basin from Vancouver Island, Canada, to Cape Mendocino, California, United States, have been investigated with swath bathymetry; newly collected and archive piston, gravity, kasten, and box cores; and accelerator mass spectrometry radiocarbon dates. The purpose of this study is to test the applicability of the Holocene turbidite...
Authors
Chris Goldfinger, C. Hans Nelson, Ann E. Morey, Joel E. Johnson, Jason R. Patton, Eugene B. Karabanov, Julia Gutierrez-Pastor, Andrew T. Eriksson, Eulalia Gracia, Gita Dunhill, Randolph J. Enkin, Audrey Dallimore, Tracy Vallier
Was this page helpful?