Publications
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An efficient mode-splitting method for a curvilinear nearshore circulation model An efficient mode-splitting method for a curvilinear nearshore circulation model
A mode-splitting method is applied to the quasi-3D nearshore circulation equations in generalized curvilinear coordinates. The gravity wave mode and the vorticity wave mode of the equations are derived using the two-step projection method. Using an implicit algorithm for the gravity mode and an explicit algorithm for the vorticity mode, we combine the two modes to derive a mixed...
Authors
Fengyan Shi, James T. Kirby, Daniel M. Hanes
Amplitude loss of sonic waveform due to source coupling to the medium Amplitude loss of sonic waveform due to source coupling to the medium
In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism...
Authors
Myung W. Lee, William F. Waite
Waveform inversion of volcano-seismic signals for an extended source Waveform inversion of volcano-seismic signals for an extended source
[1] We propose a method to investigate the dimensions and oscillation characteristics of the source of volcano-seismic signals based on waveform inversion for an extended source. An extended source is realized by a set of point sources distributed on a grid surrounding the centroid of the source in accordance with the source geometry and orientation. The source-time functions for all...
Authors
M. Nakano, Hiroyuki Kumagai, B. Chouet, P. Dawson
Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate 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...
Authors
T.S. Yun, J.C. Santamarina, C. Ruppel
Role of sediment resuspension in the remobilization of particulate-phase metals from coastal sediments Role of sediment resuspension in the remobilization of particulate-phase metals from coastal sediments
The release of particulate-phase trace metals due to sediment resuspension has been investigated by combining erosion chamber experiments that apply a range of shear stresses typically encountered in coastal environments with a shear stress record simulated by a hydrodynamic model. Two sites with contrasting sediment chemistry were investigated. Sediment particles enriched in silver...
Authors
Linda H. Kalnejais, William R. Martin, Richard P. Signell, Michael H. Bothner
Barrier island vulnerability to breaching: a case study on Dauphin Island, Alabama Barrier island vulnerability to breaching: a case study on Dauphin Island, Alabama
Breaching of barrier islands can adversely impact society by severing infrastructure, destroying private properties, and altering water quality in back bays and estuaries. This study provides a scheme that assesses the relative vulnerability of a barrier island to breach during storms. Dauphin Island, Alabama was selected for this study because it has a well documented history of island...
Authors
Mark Hansen, Asbury H. Sallenger
Titan's surface from Cassini RADAR SAR and high resolution radiometry data of the first five flybys 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...
Authors
F. Paganelli, Michael A. Janssen, B. Stiles, R. West, Ralf D. Lorenz, Jonathan I. Lunine, Stephen D. Wall, Philip S. Callahan, Rosaly Lopes, Ellen R. Stofan, Randolph L. Kirk, W.T.K. Johnson, L. Roth, Charles Elachi
An assessment of ichthyofaunal assemblages within the mangal of the Belize offshore cays An assessment of ichthyofaunal assemblages within the mangal of the Belize offshore cays
We assessed ichthyofaunal diversity within offshore mangrove cays in Belize during three, 2-wk surveys (2003, 2004, 2005). Nine sampling gears were deployed in pre-defined micro-habitats: fringe, transition, dwarf red mangrove, internal creeks, ponds, and sinkholes. Water quality data (temperature, salinity, DO) were taken during most collections. A total of 2586 gear sets was completed...
Authors
D.S. Taylor, E.A. Reyier, C.C. McIvor, W.P. Davis
New estimates for Io eruption temperatures: Implications for the interior New estimates for Io eruption temperatures: Implications for the interior
The initial interpretation of Galileo data from Jupiter's moon, Io, suggested eruption temperatures ≥1600°C. Tidal heating models have difficulties explaining Io's prodigious heat flow if the mantle is >1300°C, although we suggest that temperatures up to ~1450°C may be possible. In general, Io eruption temperatures have been overestimated because the incorrect thermal model has been...
Authors
Laszlo P. Keszthelyi, Windy L. Jaeger, Moses P. Milazzo, Jani Radebaugh, Ashley G. Davies, Karl L. Mitchell
Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat
The colonial ascidian Didemnum sp. has colonized northwestern Atlantic coastal habitats from southern Long Island, New York, to Eastport, Maine. It is also present in offshore habitats of the Georges Bank fishing grounds. It threatens to alter fisheries habitats and shellfish aquacultures. Observations in a tide pool at Sandwich, MA from December 2003 to February 2006 show that Didemnum...
Authors
P. C. Valentine, M.R. Carman, D.S. Blackwood, E.J. Heffron
Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper
The Cassini Titan Radar Mapper obtained Synthetic Aperture Radar images of Titan's surface during four fly-bys during the mission's first year. These images show that Titan's surface is very complex geologically, showing evidence of major planetary geologic processes, including cryovolcanism. This paper discusses the variety of cryovolcanic features identified from SAR images, their...
Authors
Rosaly Lopes, K. L. Mitchell, Ellen R. Stofan, Jonathan I. Lunine, Ralf D. Lorenz, F. Paganelli, Randolph L. Kirk, C. A. Wood, Stephen D. Wall, L.E. Robshaw, A.D. Fortes, Catherine D. Neish, Jani Radebaugh, E. Reffet, S.J. Ostro, Charles Elachi, M.D. Allison, Y. Anderson, R. Boehmer, G. Boubin, Philip S. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, Michael A. Janssen, W.T.K. Johnson, K. Kelleher, D.O. Muhleman, G. Ori, R. Orosei, G. Picardi, F. Posa, L.E. Roth, R. Seu, S. Shaffer, Laurence A. Soderblom, B. Stiles, S. Vetrella, R.D. West, L. Wye, H. A. Zebker
Progress in the development of shallow-water mapping systems 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...
Authors
E. Bergeron, C.R. Worley, T. O'Brien