Publications
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Sorted bed forms as self-organized patterns: 2. complex forcing scenarios
We employ a numerical model to study the development of sorted bed forms under a variety of hydrodynamic and sedimentary conditions. Results indicate that increased variability in wave height decreases the growth rate of the features and can potentially give rise to complicated, a priori unpredictable, behavior. This happens because the system responds to a change in wave characteristics by attemp
Authors
Giovanni Coco, A. Brad Murray, Malcom O. Green, E. Robert Thieler, T.M. Hume
System for ranking relative threats of U.S. volcanoes
A methodology to systematically rank volcanic threat was developed as the basis for prioritizing volcanoes for long-term hazards evaluations, monitoring, and mitigation activities. A ranking of 169 volcanoes in the United States and the Commonwealth of the Northern Mariana Islands (U.S. volcanoes) is presented based on scores assigned for various hazard and exposure factors. Fifteen factors define
Authors
John W. Ewert
Generation and propagation of nonlinear internal waves in Massachusetts Bay
During the summer, nonlinear internal waves (NLIWs) are commonly observed propagating in Massachusetts Bay. The topography of the area is unique in the sense that the generation area (over Stellwagen Bank) is only 25 km away from the shoaling area, and thus it represents an excellent natural laboratory to study the life cycle of NLIWs. To assist in the interpretation of the data collected during t
Authors
A. Scotti, R.C. Beardsley, B. Butman
Titan's surface from Cassini RADAR SAR and high resolution radiometry data of the first five flybys
The first five Titan flybys with Cassini's Synthetic Aperture RADAR (SAR) and radiometer are examined with emphasis on the calibration and interpretation of the high-resolution radiometry data acquired during the SAR mode (SAR-radiometry). Maps of the 2-cm wavelength brightness temperature are obtained coincident with the SAR swath imaging, with spatial resolution approaching 6 km. A preliminary c
Authors
F. Paganelli, Michael A. Janssen, B. Stiles, R. West, Ralf D. Lorenz, Jonathan I. Lunine, Stephen D. Wall, Philip S. Callahan, Rosaly M.C. Lopes, Ellen R. Stofan, Randolph L. Kirk, W.T.K. Johnson, L. Roth, Charles Elachi
Coupled changes in sand grain size and sand transport driven by changes in the upstream supply of sand in the Colorado River: relative importance of changes in bed-sand grain size and bed-sand area
Sand transport in the Colorado River in Marble and Grand canyons was naturally limited by the upstream supply of sand. Prior to the 1963 closure of Glen Canyon Dam, the river exhibited the following four effects of sand supply limitation: (1) hysteresis in sediment concentration, (2) hysteresis in sediment grain size coupled to the hysteresis in sediment concentration, (3) production of inversely
Authors
D.J. Topping, D. M. Rubin, T.S. Melis
Using topographic lidar data to delineate the North Carolina Shoreline
In North Carolina, shoreline change rates are an important component of the state's coastal management program. To enhance methods of measuring shoreline change, the NC Division of Coastal Management (DCM) is considering using mean high water (MHW) shorelines extracted from lidar data together with traditional wet/dry shorelines digitized from aerial photography. To test their compatibility, a wet
Authors
Patrick W. Limber, Jeffrey H. List, Jeffrey D. Warren, Amy S. Farris, Kathryn M. Weber
Characterisation and modelling of washover fans
Pre- and post-storm topography and aerial photography, collected in regions where new washover fans were formed, were studied to determine the extent of morphologic, vegetative and anthropogenic control on washover shape and extent. When overwash is funnelled through a gap in a dune ridge and then spreads laterally on the back barrier, decelerating and depositing sediment, it forms washover fans.
Authors
Chantal Donnelly, Asbury H. Sallenger
Progress in the development of shallow-water mapping systems
The USGS (US Geological Survey) Coastal and Marine Geology has deployed an advance autonomous shallow-draft robotic vehicle, Iris, for shallow-water mapping in Apalachicola Bay, Florida. The vehicle incorporates a side scan sonar system, seismic-reflection profiler, single-beam echosounder, and global positioning system (GPS) navigation. It is equipped with an onboard microprocessor-based motor co
Authors
E. Bergeron, C.R. Worley, T. O'Brien
Interferogram formation in the presence of complex and large deformation
Sierra Negra volcano in Isabela island, Galápagos, erupted from October 22 to October 30 in 2005. During the 8 days of eruption, the center of Sierra Negra's caldera subsided about 5.4 meters. Three hours prior to the onset of the eruption, an earthquake (Mw 5.4) occurred, near the caldera. Because of the large and complex phase gradient due to the huge subsidence and the earthquake, it is difficu
Authors
S.-H. Yun, H. Zebker, P. Segall, A. Hooper, Michael P. Poland
Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate
The mechanical behavior of hydrate-bearing sediments subjected to large strains has relevance for the stability of the seafloor and submarine slopes, drilling and coring operations, and the analysis of certain small-strain properties of these sediments (for example, seismic velocities). This study reports on the results of comprehensive axial compression triaxial tests conducted at up to 1 MPa con
Authors
T.S. Yun, J.C. Santamarina, C. Ruppel
Barite-forming environments along a rifted continental margin, Southern California Borderland
The Southern California Continental Borderland (SCCB) is part of the broad San Andreas transform-fault plate boundary that consists of a series of fault-bounded, petroleum-generating basins. The SCCB has high heat flow and geothermal gradients produced by thinned continental crust and Neogene volcanism. Barite deposits in the SCCB occur along faults.Barite samples from two sea-cliff sites and four
Authors
James R. Hein, Robert A. Zierenberg, J. Barry Maynard, Mark D. Hannington
Initial insights from 2.5D hydraulic modeling of floods in Athabasca Valles, Mars
We present the first application of a 2.5D hydraulic model to catastrophic floods on Mars. This model simulates flow over complex topography and incorporates flood dynamics that could not be modeled in the earlier 1D models. We apply this model to Athabasca Valles, the youngest outflow channel on Mars, investigating previous bank-full discharge estimates and utilizing the interpolated Mars Orbiter
Authors
Laszlo P. Keszthelyi, Roger P. Denlinger, D. R. H. O'Connell, Devon M. Burr