CPT-based seismic stability assessment of a hazardous waste site

In areas of high seismicity, seismic stability often controls hazardous and solid waste landfill closure design. The undrained shear strength (S_u) of the waste mass is fundamental to seismic slope stability analyses. The value of S_u for hazardous waste fill is often difficult to characterize. The physical and chemical natures of the waste fill typically preclude laboratory testing of the materials. In certain cases, Cone Penetration Test (CPT) soundings can provide a viable technique for evaluation of S_u provided that the cone shear strength factor N_k can be established. If hazardous waste materials laboratory testing is not an option, N_k may be evaluated based upon results of non-intrusive in situ testing. This paper presents a case history of the seismic stability assessment of a hazardous waste site in which N_k was established from the results of non-intrusive Spectral Analysis of Surface Waves (SASW) soundings and empirical correlations to shear strength of soils. Generalization of the proposed methodology to other sites should be done with caution owing to variability among the parameters used in the analyses.     

Calculation of 5250.216 Å line profiles in sunspots

The assumptions of pure absorption and local thermodynamic equilibrium are sometimes used to calculate approximate spectral line profiles in cases where a rigorous treatment is impractical or impossible. In certain conditions, the profile is not completely defined under these assumptions.This work was done under NASA contract No. NAS8-26376 for the Space Sciences Laboratory, George C. Marshall Space Flight Center, Huntsville, Ala.     

Preparing The National Map for the 3D Elevation Program – products,process and research

The 3D Elevation Program (3DEP) is a collaborative effort among government entities, academia, and the private sector to collect high-resolution 3-dimensional data over the United States. The United States Geological Survey (USGS) is making preparations for managing, processing, and delivering petabytes of 3DEP elevation products for the Nation. In addition to the existing 1/3, 1, and 2 arc-second seamless elevation data layers of The National Map, new 3DEP products include lidar point cloud data; a standard 1-meter DEM layer; additional source datasets; and, in Alaska, 5-meter digital elevation models. A new product generation system improves the construction and publication of the seamless elevation datasets, prepares the additional 3DEP products for distribution, and automates the data management functions required to accommodate the high-volume 3DEP data collection. Major changes in geospatial data acquisition, such as high resolution lidar data, volunteered geographic information, data processing using parallel and grid computer systems, and user needs for semantic access to geospatial data and products, are driving USGS research associated with the 3DEP. To address the research requirements, a set of inter-related projects including spatiotemporal data models, data integration, geospatial semantics and ontology, high performance computing, multi-scale representation, and hydrological modeling using lidar and other 3DEP data has been developed.     

Patterns of tidal flooding within a mangrove forest: Coombabah Lake,Southeast Queensland,Australia

Tidal flooding and surface drainage patterns have often been used to describe mangrove species zonation. However, in mangrove forests exhibiting little topography, ambiguous species distributions and/or few species, such approaches are ineffective. We identified four physiognomic mangrove forest types (Riverine, Fringing, Overwash and Basin) at Coombabah Lake, a tidal lake in southeast Queensland, Australia and investigated tidal flooding patterns using synoptic surveys of tidal observations at the local Standard Port combined with local water depth observation. Subsequently three sub-types of the basin forest type were identified: (1) Deep Basin Forest with mature trees, ∼50 cm standing water and ∼3 tides per year; (2) Medium Depth Basin Forest with intermediate tree development, ∼15–30 cm standing water and 20–40 tides per year; and (3) Shallow Basin Forest with relatively recent mangrove establishment, 5–15 cm standing water and ∼80 tides per year. These three basin sub-types were found to flood at different tide heights with the Shallow Basin flooding for tides above mean high water springs and the Deep Basin flooding only for tide heights approaching the highest astronomical tide. We propose that these basin types represent a succession in mangrove forest development that corresponds with increasing water depth and tree maturation over time. The succession not only represents increasing age but also change in basin substrate composition. This is manifest as increasing pneumatophore density and an increasing area of basin surface occupied by contiguous pneumatophore cover. As a result, it seems that mangrove development is able to modify tidal flooding into the basin by increasingly impeding water movement.     

Promising signs of regeneration of blue cod and oyster habitat changed by dredging in Foveaux Strait,southern New Zealand

Epifaunal reefs in Foveaux Strait are oyster (Ostrea chilensis Philippi, 1845) habitat. One hundred and thirty years of oyster dredging has diminished the complexity and distribution of these reefs. Commercial densities of blue cod (Parapercis colias (Forster in Bloch and Schneider, 1801)) were discovered on epifaunal reef habitat in 1989 and became the focus of a major blue cod fishery. We document habitat changes that followed the closing of the oyster fishery in 1993 and interactions between the blue cod and oyster fisheries after the oyster fishery was reopened in 1996. Evidence from blue cod fishers and oyster surveys suggests that the benthic habitat of some oyster beds regenerated in the absence of dredging and that the relative density of blue cod, and then oysters, rebuilt to commercial levels. Benthic habitat was modified once more when oyster dredging restarted and the relative density of blue cod on oyster beds fell again. The observations suggest that rotational fishing of oysters could mitigate the effects of dredging on habitat and that marine protected areas could expedite habitat recovery. Increasing habitat complexity and blue cod density on a reef of oyster shells formed by an oyster fisher suggests that habitat enhancement might remedy effects of dredging. The questions raised by the observations could be answered by management experiments on the scale of the fisheries.     

Geo-information tools for participatory spatial planning: Fulfilling the criteria for ‘good’ governance?

The last few decades have seen increasing attempts to foster ‘collaborative’ and ‘participatory’ approaches to spatial planning and decision-making, with a more sophisticated conceptualisation of the contested term, participation. Participatory, ‘bottom-up’ geo-information technologies have been concurrently developing and these are expected to strengthen participatory spatial planning; important among these has been the transformation of conventional mapping and GIS tools into Participatory GIS (PGIS). In this paper we explore the potential contributions of participatory geo-information tools towards participatory spatial planning, in terms of the principles and criteria of good governance. We discuss five fundamental principles of ‘good’ governance: accountability, legitimacy, respect, equity, and competence, and the potential of geo-information tools to contribute to, and detract from, such principles; although we focus especially on participation and the recognition and validation of local knowledge. We derive criteria for the five principles, and we identify a range of evaluation questions which can be operationalised so as to interrogate the criteria for judging the contribution of participatory tools and participatory spatial planning activities. We conclude by summarily assessing the potentials of participatory geo-information tools, particularly participatory mobile GIS, participatory 3-dimensional modelling, and visualisation features in PGIS.     

Triact spicules in proterozoic rocks of the Northern Territory of Australia

Triact fragments, probably of sponge spicules, occur in a siliceous rock found in the Proterozoic succession along the coast of the Gulf of Carpentaria in the Northern Territory of Australia.     

Analysis of radial basis function interpolation approach

The radial basis function （RBF） interpolation approach proposed by Freedman is used to solve inverse problems encountered in well-logging and other petrophysical issues. The approach is to predict petrophysical properties in the laboratory on the basis of physical rock datasets, which include the formation factor, viscosity, permeability, and molecular composition. However, this approach does not consider the effect of spatial distribution of the calibration data on the interpolation result. This study proposes a new RBF interpolation approach based on the Freedman＇s RBF interpolation approach, by which the unit basis functions are uniformly populated in the space domain. The inverse results of the two approaches are comparatively analyzed by using our datasets. We determine that although the interpolation effects of the two approaches are equivalent, the new approach is more flexible and beneficial for reducing the number of basis functions when the database is large, resulting in simplification of the interpolation function expression. However, the predicted results of the central data are not sufficiently satisfied when the data clusters are far apart.