Calculation of lava effusion rates from Landsat TM data

 We present a thermal model to calculate the total thermal flux for lava flowing in tubes, on the surface, or under shallow water. Once defined, we use the total thermal flux to estimate effusion rates for active flows at Kilauea, Hawaii, on two dates. Input parameters were derived from Landsat Thematic Mapper (TM), field and laboratory measurements. Using these parameters we obtain effusion rates of 1.76±0.57 and 0.78±0.27 m³ s^–1 on 23 July and 11 October 1991, respectively. These rates are corroborated by field measurements of 1.36±0.14 and 0.89±0.09 m³s^–1 for the same dates (Kauahikaua et al. 1996). Using weather satellite (AVHRR) data of lower spatial resolution, we obtain similar effusion rates for an additional 26 dates between the two TM-derived measurements. We assume that, although total effusion rates at the source declined over the period, the shut down of the ocean entry meant that effusion rates for the surface flows alone remained stable. Such synergetic use of remotely sensed data provides measurements that can (a) contribute to monitoring flow-field evolution, and (b) provide reliable numerical data for input into rheological and thermal models. We look forward to being able to produce estimates for effusion rates using data from high-spatial-resolution sensors in the earth observing system (EOS) era, such as Landsat 7, the hyperspectral imager, the advanced spaceborne thermal emission spectrometer, and the advanced land imager. Received: 25 July 1997 / Accepted: 26 February 1998     

RBCA Closure at DNAPL Sites

The closure of sites with identified or suspected DNAPL (dense nonaqueous phase liquids) under the requirements of the Resources Conservation and Recovery Act of 1976 (RCRA), or the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) has not been well defined. With respect to RCRA, the U.S. Environmental Protection Agency (EPA) has required that all contamination must be removed at closure such that no residual risk to human health or the environment remains. Therefore, even though many states administering the RCRA program have adopted or are considering Risk-Based Corrective Action (RBCA) procedures (including the statistical methods described in SW-846) for RCRA closure, the treatment of DNAPL is, at best, challenging.
The methodology for closure in CERCLA is described in "Risk Assessment Guidelines for Super-fund (RAGS)," which requires that risks above the National Contingency Plan criteria must be remediated, preferably by on-site or in situ destruction. Most risk-based Brownfield or voluntary cleanup programs do not provide any explicit allowance for DNAPL. However, while the ASTM methodology for RBCA in E1739-95 (ASTM 1995) does not explicitly treat the problem of DNAPL, a basic framework for DNAPL assessment is implicitly provided.
A uniform methodology for RBCA closure of VOC (volatile organic compounds) DNAPL sites can be used to achieve the program objectives of RCRA, CERCLA, and Brownfield or voluntary cleanup programs. The regulatory acceptance of the application of RBCA methods to DNAPL sites will require education and discussion, but the use of a uniform methodology should facilitate acceptance.     

Inflation and the Cosmic Microwave Background

I give a status report and outlook concerning the use of the cosmic microwave background anisotropies to constrain the inflationary cosmology, and stress its crucial role as an underlying paradigm for the estimation of cosmological parameters. This revised version was published online in July 2006 with corrections to the Cover Date.     

Looking Down the Light Cone: Can Deep Redshift Surveys Alone Measure the Power Spectrum?

We analyse the window functions for the spherical harmonic mode estimators of all-sky, volume-limited surveys, considering evolutionary effects along the past light-cone which include the deviation of the distance scale from a linear relationship with redshift, linear peculiar velocity corrections, and linear evolution of the density perturbations. The spherical harmonic basis functions are considered, because they correspond most closely to the symmetries of typical survey geometries and of the light-cone effects we consider. Our results show substantial broadening of the windows over that expected by ignoring light-cone effects, indicating the difficulty of measuring the power spectrum independently from cosmology. We suggest that because of light-cone effects, deep redshift surveys should be analysed either in conjunction with CMBR data which determines the cosmological parameters, or by using a Bayesian likelihood scheme in which varying cosmological parameters and a simple parametrization of the primordial power spectrum are assumed as the priors, so that observed data can be mapped from redshift to real space. The derived power spectrum can then be compared with underlying models of fluctuation generation and growth in structure formation to evaluate both these models and the cosmological priors.     

Seasonal trends in the uranium-series istopic signatures of lake waters and sediments: Hawes Water, north-west England

Potential seasonal variation in the U-series radioisotopic signatures of lake and input waters was investigated in Hawes Water, north-west England, and the sedimentary record was examined to establish whether any observed seasonality is preserved in the sediment U and Th radioisotopic activity ratios. U-series disequilibrium in the waters is indicative of both surface and shallow sub-surface origins for the dissolved U, and that this supply is influenced by changes in the prevailing hydrological regime. However, the lake is buffered from this seasonality in that the ²³⁴U/²³⁸U activity ratio remains constant during the year, and the U content undergoes only a marginal decrease during summer. The change in the mechanism of lake sedimentation from allochthonous organic input during winter to autochthonous carbonate formation during summer has a more significant influence on the U-series radioisotopic characteristics of sedimentary record in that the proportion of organic and carbonate material both exhibit a strong control on the²³⁴U/²³⁸U activity ratio and U content. In addition, significant proportions of sediment U and Th are associated with ferromanganese oxyhydroxides. Given this seasonality, it is of some significance that the ²³⁴U/²³⁸U activity ratios of the bottom sediments preserve a reasonable record of lake U-series disequilibrium and are, therefore, potential indicators of long-term changes in catchment hydrology.     

Reconstruction of paleoenvironments of the Great Salt Lake Basin during the late Cenozoic

This study summarizes the results of micropaleontological, sedimentological, and isotope geochemical analyses of cuttings from five deep wells drilled in the Great Salt Lake (Utah, USA). Spanning the last 5.0 million yrs, our environmental history of the Great Salt Lake distinguishes four intervals based on paleobiological and sedimentological characteristics, using a previously developed tephrochronology for age control. For most of its history, the Great Salt Lake Basin has been occupied by a mixture of marsh, shallow lacustrine and sand flat conditions. In contrast, open lake conditions, typical of the Bonneville cycles and the modern Great Salt Lake apparently have only dominated the basin for the past 0.6-0.8 Ma. The two main structural basins in the study area (the North and South Basins) experienced different lacustrine histories. Large but frequently saline lakes occupied the North Basin after about 0.6 Ma. In the South Basin, ephemeral, saline lacustrine conditions started at 2.1 Ma and developed to full lacustrine conditions at 0.3 Ma. Our paleoenvironmental interpretations are broadly consistent with the aquatic palynological records from the same wells, as well as with the prior core- and outcrop-based lines of evidence. However, the differences in lake history between the North and South Basin have not been previously recognized.     

A kite based atmospheric sounding system

A newly developed kite based atmospheric sounding system is described that can be deployed under a wide range of weather conditions. The Delta Kite system can be flown in wind speeds ranging from 4 to 25 ms^-1, while the exceptional lift capabilities of the kite allow several kilograms of payload to be attached to the kite and/or tether. In conjunction with its battery powered winch, the Delta Kite atmospheric sounding system is ideally suited to meteorological studies in remote locations where vehicle access may not be possible.     

Significance of rare hydrous alkaline melts in Hawaiian xenoliths

 Two types of melt pockets occur in Hawaiian mantle xenoliths: amphibole-bearing (AMP) and spinel-bearing (SMP). AMPs contain amphibole (kaersutite), olivine (Fo₉₂), clinopyroxene (with 7–11% Al₂O₃), vesicles and glass. SMPs contain olivine, clinopyroxene, spinel, glass, and vesicles. The glasses in SMPs (SiO₂=44–45%, 11–12% alkalis, La=90–110 ppm) and AMPs (SiO₂=49–54%, 6–8.5% alkalis, La=8–14 ppm) are distinct in color and composition. Both glasses are generally characterized by LREE-enriched (chondrite-normalized) patterns. Amphibole and clinopyroxene have gently convex upward-to-moderately LREE-enriched patterns. Mineral/glass trace element abundance ratio plots show a strong negative Ti anomaly and a gentle negative Zr anomaly for clinopyroxene/glass; whereas amphibole/glass patterns show a distinctive positive Ti spike. The amphibole/glass trace element ratios are similar to published megacryst/lava values. An earlier study showed that the Hawaiian spinel lherzolites (lithosphere) have largely been metasomatized during post-erosional Honolulu magmatic activity. REE abundances of SMP glasses (melts) overlap the REE abundances calculated for such metasomes. The occurrence of hydrous, alkaline, mafic melt pockets in Hawaiian upper mantle xenoliths implies that (1) such hydrous liquids are generated in the upper mantle, and (2) water plays a role in magmatic activity associated with the Hawaiian plume. Although we are uncertain about the source (plume, lithosphere, or asthenosphere) of this water, we speculate that such melts and other alkalic lavas erupted on Oahu and on the sea-floor over the Hawaiian arch were generated from a broad „wet“ rim of a radially layered Hawaiian plume, whose hot and „dry“ core supplied the shield-forming magmas. Received: 6 February 1995 / Accepted: 28 August 1995