Publications
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Surface properties of Mars' polar layered deposits and polar landing sites
On December 3, 1999, the Mars Polar Lander and Mars Microprobes will land on the planet's south polar layered deposits near (76°S, 195°W) and conduct the first in situ studies of the planet's polar regions. The scientific goals of these missions address several poorly understood and globally significant issues, such as polar meteorology, the composition and volatile content of the layered deposits
Authors
Ashwin R. Vasavada, Jean-Pierre Williams, David A. Paige, Kenneth E. Herkenhoff, Nathan T. Bridges, Ronald Greeley, Bruce C. Murray, Deborah S. Bass, Karen S. McBride
The state and future of Mars polar science and exploration
As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of ∼106 km2 and total as much as 3–4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young—preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust
Authors
S.M. Clifford, D. Crisp, D.A. Fisher, Kenneth E. Herkenhoff, S.E. Smrekar, P. C. Thomas, D. D. Wynn-Williams, R.W. Zurek, J.R. Barnes, B.G. Bills, E.W. Blake, W. M. Calvin, J.M. Cameron, M. H. Carr, P. R. Christensen, B. C. Clark, G.D. Clow, J.A. Cutts, D. Dahl-Jensen, W. B. Durham, F. P. Fanale, J.D. Farmer, F. Forget, K. Gotto-Azuma, R. Grard, R.M. Haberle, W. Harrison, R. Harvey, A.D. Howard, A.P. Ingersoll, P.B. James, J.S. Kargel, H. H. Kieffer, J. Larsen, K. Lepper, M. C. Malin, D. J. McCleese, B. Murray, J.F. Nye, D. A. Paige, S.R. Platt, J.J. Plaut, N. Reeh, J.W. Rice, D.E. Smith, C. R. Stoker, K. L. Tanaka, E. Mosley-Thompson, T. Thorsteinsson, S.E. Wood, A. Zent, M.T. Zuber, H.J. Zwally
Hydrogen defects in α-Al2O3 and water weakening of sapphire and alumina ceramics between 600°C and 1000°C: II. Mechanical properties
Hydrogen impurities in alumina have been introduced by hydrothermal annealing (see part I). In this paper, we report on reductions in the flow strength of α-Al2O3 single crystals and polycrystals associated with hydrogen incorporation. Prior to deformation, α-Al2O3 single crystal and ceramic specimens were annealed in the presence of supercritical water at 850° or 900°C, under 1500 MPa pressure. S
Authors
J. Castaing, A. K. Kronenberg, S. H. Kirby, T. E. Mitchell
Gravitational stability of three-dimensional stratovolcano edifices
Catastrophic flank collapses have occurred at many stratovolcanoes worldwide. We present a three-dimensional (3-D) slope stability analysis for assessing and quantifying both the locations of minimum edifice stability and the expected volumes of potential failure. Our approach can search the materials underlying a topographic surface, represented as a digital elevation model (DEM), and determine t
Authors
M.E. Reid, S.B. Christian, D.L. Brien
Surface ages and resurfacing rates of the Polar Layered Deposits on Mars
Interpretation of the polar stratigraphy of Mars in terms of global climate changes is complicated by the significant difference in surface ages between the north and south polar layered terrains inferred from crater statistics. We have reassessed the cratering record in both polar regions using Viking Orbiter and Mariner 9 images. No craters have been found in the north polar layered terrain, but
Authors
Kenneth E. Herkenhoff, Jeffrey J. Plaut
Archive report for most USGS seismic refraction investigations conducted between 1978 and 1991
In 1978, the U.S. Geological Survey (USGS) began acquiring seismic refraction data throughout the U.S. and Saudi Arabia. Numerous professional papers have been published in the literature and the technical details and goals for most of these surveys have been described in USGS Open-file reports (Table 1). This report describes the archiving of the data.
Authors
Janice M. Murphy
Landslide triggering by rain infiltration
Landsliding in response to rainfall involves physical processes that operate on disparate timescales. Relationships between these timescales guide development of a mathematical model that uses reduced forms of Richards equation to evaluate effects of rainfall infiltration on landslide occurrence, timing, depth, and acceleration in diverse situations. The longest pertinent timescale is A/D0, where
Authors
Richard M. Iverson
Mars south polar spring and summer behavior observed by TES: seasonal cap evolution controlled by frost grain size
Thermal Emission Spectrometer (TES) observations of the recession phase of Mars' south polar cap are used to quantitatively map this recession in both thermal and visual appearance. Geographically nonuniform behavior interior to the cap is characterized by defining several small regions which exemplify the range of behavior. For most of the cap, while temperatures remain near the CO2 frost point,
Authors
Hugh H. Kieffer, Timothy N. Titus, Kevin F. Mullins, Phillip R. Christensen
Taking the Earth's Pulse
During the past 35 years, scientists have developed a vast network of seismometers that record earthquakes, volcanic eruptions, and nuclear explosions throughout the world. Seismographic data support disaster response, scientific research, and global security. With this network, the United States maintains world leadership in monitoring the greatest natural and technological events that threaten o
Authors
Robert L. Woodward, Harley Mitchell Benz, Kaye M. Shedlock, William M. Brown
Seasonal movement of the Slumgullion landslide as determined from GPS observations, July 1998-July 1999
No abstract available.
Authors
J. A. Coe, J. W. Godt, W. L. Ellis, W. Z. Savage, J. E. Savage, P. S. Powers, D. J. Varnes, P. Tachker
Preliminary interpretation of seasonal movement of the Slumgullion landslide as determined from GPS observations, July 1998-July 1999
No abstract available.
Authors
J. A. Coe, J. W. Godt, W. L. Ellis, W. Z. Savage, J. E. Savage, P. S. Powers, D. J. Varnes, P. Tachker
Landslide-induced flooding at Ophir Creek, Washoe County, western Nevada, May 30, 1983
Rapid spilling of 22 acre-feet of water down the steep, 3-mile channel of Ophir Creek killed one, injured four, and destroyed or damaged five houses. Flow evolved into debris flow enroute, and compounded in volume over 30 times.
Authors
Patrick A. Glancy, John W. Bell