Faults within outcrops of Permo-Triassic sandstones from NW England have been analysed, and their throws and fault zone thicknesses measured. These data were collected in order to provide a basis for estimating fault zone transmissibility. Logarithmic plots of fault throw versus fault zone thickness from the same localities show a positive correlation, and this relationship can be used to estimate fault zone thicknesses from fault throws derived from seismic data within similar successions. By combining fault zone thickness with laboratory-derived measurements of fault zone permeability, we show that fault transmissibilities can be estimated for input into reservoir simulation. These results can be applied to the assessment of seal potential and transmissibility in offshore oil and gas fields reservoired in Permo-Triassic sandstones. Layer thickness has a control on the fault populations, giving rise to separate population slopes for faults contained within a distinctive layer compared with those that extend outwith the layer. If layer thickness effects are not taken into account, extrapolation of a single power law trend may lead to an overestimation of the number of small faults in a population.
Hurricanes are known to play a critical role in reshaping coastlines, but often only impacts on the open ocean coast are considered, ignoring seaward-directed forces and responses. The identification of subaerial evidence for storm-induced seaward transport is a critical step towards understanding its impact on coastal resiliency. The visual features, found in the National Oceanic and Atmospheric Administration, National Geodetic Survey Emergency Response Imagery (ERI) collected after recent hurricanes on the U.S. East Atlantic and Gulf of Mexico coasts, include scours and channelized erosion, but also deposition on the shoreface or in the nearshore as deltas and fans of various sizes. We catalog all available ERI and describe recently formed features found on the North Core Banks, North Carolina, after Hurricane Dorian (2019); the Carolina coasts after Hurricane Isaias (2020); the Isles Dernieres, Louisiana, after Hurricane Zeta (2020); and the southwest coast of Louisiana, after Hurricanes Laura and Delta (2020). Hundreds of features were identified over nearly 200 km of coastline with the density of features exceeding 20 per km in some areas. Individual features range in size from 5 m to 500 m in the alongshore, with similar dimensions in the cross-shore direction, including the formation or reactivation of outlets. The extensive occurrence of these storm-induced return-flow and seawardflow morphologic features demonstrates that their role in coastal evolution and resilience may be more prominent than previously thought. Based on these observations we propose clarifying terms for return- and seaward-flow features to distinguish them from more frequently documented landward-flow features and advocate for their inclusion in coastal change hazards classification schemes and coastal evolution morphodynamic models.
Cleanup standards for volatile organic compounds in thick vadose zones can be based on indirect risk (transport to ground water) when contamination is below depths of significant direct risk. At one Arizona Superfund site, a one‐dimensional vadose zone transport model (VLE‐ACH) was used to estimate the continued transport of VOCs from the vadose zone to ground water. VLEACH is a relatively simple and readily available model that proved useful for estimating indirect risk from VOCs in the vadose zone at this site. The estimates of total soil concentrations used as initial conditions for VLF.ACH incorporated a variety of data from the site. Soil gas concentrations were found to be more useful than soil matrix data for estimating total soil concentrations at this arid‐zone site. A simple mixing cell model was used with the VLEACH‐derived mass loading estimates from the vadose zone over time to estimate the resulting changes in ground water concentrations. For this site, the results of the linked VLEACH/mixing cell simulations indicate it is likely that the federal MCI. for TCE will be exceeded in underlying ground water if remedial action on I he vadose zone is not pursued.
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