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Modeling sediment bypassing around idealized rocky headlands

Alongshore sediment bypassing rocky headlands remains understudied despite the importance of characterizing littoral processes for erosion abatement, beach management, and climate change adaptation. To address this gap, a numerical model sediment transport study was developed to identify controlling factors and mechanisms for sediment headland bypassing potential. Four idealized headlands were des
Authors
Douglas A. George, John L. Largier, Greg B. Pasternack, Patrick L. Barnard, Curt D. Storlazzi, Li H. Erikson

Permeability anisotropy and relative permeability in sediments from the National Gas Hydrate Program Expedition 02, offshore India

Gas and water permeability through hydrate-bearing sediments essentially governs the economic feasibility of gas production from gas hydrate deposits. Characterizing a reservoir’s permeability can be difficult because even collocated permeability measurements can vary by 4-5 orders of magnitude, due partly to differences between how various testing methods inherently measure permeability in differ
Authors
Sheng Dai, J. Kim, Yue Xu, William F. Waite, Junbong Jang, J. Yoneda, Timothy S. Collett, Pushpendra Kumar

Physical property characteristics of gas hydrate-bearing reservoir and associated seal sediments collected during NGHP-02 in the Krishna-Godavari Basin, in the offshore of India

India’s National Gas Hydrate Program Expedition 02 (NGHP-02), was conducted to better understand geologic controls on gas hydrate occurrence and morphology, targeting potentially coarse-grained sediments near the base of the continental slope offshore eastern India. This study combines seismic, logging-while-drilling data, and a petroleum systems approach to provide a regional geologic context fo
Authors
Junbong Jang, William F. Waite, Laura A. Stern, Timothy S. Collett, Pushpendra Kumar

Compressibility and particle crushing of Krishna-Godavari Basin sediments from offshore India: Implications for gas production from deep-water gas hydrate deposits

Depressurizing a gas hydrate reservoir to extract methane induces high effective stresses that act to compress the reservoir. Predicting whether a gas hydrate reservoir is viable as an energy resource requires enhanced understanding of the reservoir’s compressibility and susceptibility to particle crushing in response to elevated effective stress because of their impact on the long-term permeabili
Authors
J. Kim, Sheng Dai, Junbong Jang, William F. Waite, Timothy S. Collett, Pushpendra Kumar

Ensembles of ETAS models provide optimal operational earthquake forecasting during swarms: Insights from the 2015 San Ramon, California swarm

Earthquake swarms, typically modeled as time-varying changes in background seismicity that are driven by external processes such as fluid flow or aseismic creep, present challenges for operational earthquake forecasting. While the time decay of aftershock sequences can be estimated with the modified Omori law, it is difficult to forecast the temporal behavior of seismicity rates during a swarm.
Authors
Andrea L. Llenos, Andrew J. Michael

Updates to USGS national seismic hazard model (NSHM) and design ground motion maps for 2020 NEHRP recommended provisions

This presentation summarizes the proposed updates to earthquake design ground motions for the 2020 edition of the NEHRP Recommended Seismic Provisions, expected to be incorporated into the ASCE 7-22 Standard. The implications of these updates on the values of design ground motions for example locations in both conterminous and nonconterminous U.S. cities are shown and discussed.
Authors
Sanaz Rezaeian, Nicolas Luco

World’s largest dam removal reverses coastal erosion

Coastal erosion outpaces land generation along many of the world’s deltas and a significant percentage of shorelines, and human-caused alterations to coastal sediment budgets can be important drivers of this erosion. For sediment-starved and erosion-prone coasts, large-scale enhancement of sediment supply may be an important, but poorly understood, management option. Here we provide new topographi
Authors
Jonathan Warrick, Andrew W. Stevens, Ian M. Miller, Shawn R Harrison, Andrew C. Ritchie, Guy R. Gelfenbaum

Dome formation on Ceres by sold-state flow analogous to terrestrial salt tectonics

The dwarf planet Ceres’s outer crust is a complex, heterogeneous mixture of ice, clathrates, salts and silicates. Numerous large domes on Ceres’s surface indicate a degree of geological activity. These domes have been attributed to cryovolcanism, but that is difficult to reconcile with Ceres’s small size and lack of long-lived heat sources. Here we alternatively propose that Ceres’s domes form by
Authors
Michael T. Bland, D. L Buczkowski, H. G. Sizemore, A. I. Ermakov, S. D King, M. M. Sori, C. A. Raymond, J. C. Castillo-Rogez, C. T. Russell

Comparison of physical to numerical mixing with different tracer advection schemes in estuarine environments

The numerical simulation of estuarine dynamics requires accurate prediction for the transport of tracers such as temperature and salinity. During the simulation of these processes, all numerical models introduce two kinds of tracer mixing: 1) by parameterizing the tracer eddy diffusivity through turbulence models leading to a source of physical mixing and 2) discretization of the tracer advection
Authors
Tarandeep S. Kalra, Xiangyu Li, John C. Warner, W. R. Geyer, Hui Wu

Clustered BSRs: Evidence for gas hydrate-bearing turbidite complexes in folded regions, example from the Perdido Fold Belt, northern Gulf of Mexico

We describe previously undocumented but extensive gas hydrate accumulations in the mouth of Perdido Canyon in the northern Gulf of Mexico. The accumulations are located within central parts of structural domes (four-way closures) and are characterized by stacked, high-amplitude bottom simulating reflections (BSRs) that we call clustered BSRs. Seismic data from Perdido Canyon show two clustered BSR
Authors
Alexy Portnov, Ann Cook, Derek E. Sawyer, Chen Yang, Jess Hillman, William F. Waite

Physicochemical controls on zones of higher coral stress where Black Band Disease occurs at Mākua Reef, Kauaʻi, Hawaiʻi

Pervasive and sustained coral diseases contribute to the systemic degradation of reef ecosystems, however, to date an understanding of the physicochemical controls on a coral disease event is still largely lacking. Water circulation and residence times and submarine groundwater discharge all determine the degree to which reef organisms are exposed to the variable chemistry of overlying waters; und
Authors
Ferdinand Oberle, Curt D. Storlazzi, Olivia Cheriton, Renee K. Takesue, Daniel J. Hoover, Joshua B. Logan, Christina M. Runyon, Christina A. Kellogg, Cordell Johnson, Peter W. Swarzenski

Sediment and organic carbon transport and deposition driven by internal tides along Monterey Canyon, offshore California

Submarine canyons provide globally important conduits for sediment and organic carbon transport into the deep-sea. Using a novel dataset from Monterey Canyon, offshore central California, that includes an extensive array of water column sampling devices, we address how fine-grained sediment and organic carbon are transported, mixed, fractionated, and buried along a submarine canyon. Anderson-type
Authors
Katherine L. Maier, Kurt J. Rosenberger, Charles K. Paull, Roberto Gwiazda, Jenny Gales, Thomas Lorenson, James P. Barry, Peter J. Talling, Mary McGann, Jingping Xu, Eve M. Lundsten, Krystle Anderson, Steven Litvin, Daniel Parsons, Michael Clare, Stephen Simmons, Esther J. Sumner, Matthieu J.B. Cartigny