Classical globally reflected gravity field determination in modern locally oriented multiscale framework

The purpose of this paper is the canonical connection of classical global gravity field determination following the concept of Stokes (Trans Camb Philos Soc 8:672–712, 1849), Bruns (Die Figur der Erde, Publikation Königl. Preussisch. Geodätisches Institut, P. Stankiewicz Buchdruckerei, Berlin, 1878), and Neumann (Vorlesungen über die Theorie des Potentials und der Kugelfunktionen. Teubner, Leipzig, pp 135–154, 1887) on the one hand and modern locally oriented multiscale computation by use of adaptive locally supported wavelets on the other hand. The essential tools are regularization methods of the Green, Neumann, and Stokes integral representations. The multiscale approximation is guaranteed simply as linear difference scheme by use of Green, Neumann, and Stokes wavelets. As an application, gravity anomalies caused by plumes are investigated for the Hawaiian and Iceland areas.     

Living with limits: growth,resources, and climate change

Is it possible for all of humanity to enjoy the standards of living of today's high-income countries? What would happen if these limits were reached, perhaps because of climate change or a shortage of natural resources essential to production? How would society manage – or fail to manage – such limits? Notwithstanding the current financial and economic crises, these are perhaps the biggest questions confronting our species (and of a host of other species, who are the victims of our decisions). The article begins by considering the biggest economic event of our lifetimes – the ‘great convergence’ and its implications for the demand for resources. The discussion then turns to a specific limit on our development, climate change, which is different from most other limits, because it involves a global public good: the atmosphere. What such limits might mean for our civilization is discussed. One can persuade people to tackle climate change only if those concerned with the dangers persuade ordinary people that action will not come at the expense of their prosperity.     

Impact of Two "El Niño" Events of Different Intensity on the Hypoxic Soft Bottom Macrobenthos off the Central Peruvian wast

Abstract. Monthly changes in the community structure of hypoxic soft-bottom macrobenthos have been studied at a station at 34 m depth in Ancón Bay (Peru) before and during two El Niño (EN) events. Of these events, 1982-83 is considered the strongest, and 1991–93 one of the most prolonged in the 20th century. On the oceanographic scale, EN 1982–83 ranges as "very strong", whereas EN 1991–93 ranges as "moderate".
The thermal anomalies at the station during EN 1982–83 (+ 7.8 °C) were almost twice those of EN 1991–93 (+ 4.1 °C). However, the community changes were not in all cases proportional to the extent of warming. Species numbers increased in a similar way (up to 24 species from near zero in each of the two events), but maximum faunal density was five times higher, and mean biomass was twice as high in 1982–83 compared with the event a decade later. Species diversity was slightly higher during EN 1982–83, whereas successional and trophic changes occurred on a broader scale during EN 1991–93. On the whole, the impact of the long-lasting event on the small soft-bottom macrofauna was not much weaker than that of the exceptionally strong event.
The authors discuss the mechanisms which may be responsible for the differences and similarities encountered in the benthic community dynamics during these two events. Both in the unusually strong and the unusually long EN, the community revealed a pattern of early biological response several months ahead of the onset of local warming which marks the official begin of EN. The question is addressed to what extent the increase of certain parameters in the benthic community could be used for predictive purposes.     

Propagation of Love waves in surface layers of varying thickness

Summary A study is made of the scattered field which results when a Love wave is incident on a layer having an irregular surface. To obtain this solution a perturbation method is used. It is shown that the scattered field may be described by a superposition of Love waves and non-propagating disturbances. As an illustrative example, the result is applied to obtain the scattering by a triangular trough.     

Are C1 chondrites chemically fractionated? a trace element study

Six C1 chondrite samples and a C2 xenolith from the Plainview H5 chondrite were analyzed by radiochemical neutron activation for the elements Ag, Au, Bi, Br, Cd, Ce, Cs, Eu, Ge, In, Ir, Lu, Nd, Ni, Os, Pd, Pt, Rb, Re, Sb, Se, Sn, Tb, Te, Tl, Yb, and Zn. The data were combined with 9 earlier analyses from this laboratory and examined for evidence of chemical fractionation in C1 chondrites.A number of elements (Br, Rb, Cs, Au, Re, Os, Ni, Pd, Sb, Bi, In, Te) show small but correlated variations. Those of the first 8 probably reflect hydrothermal alteration in the meteorite parent body, whereas those of Sb, Bi, In, and Te may at least in part involve nebular processes. Br and Au show systematic abundance differences from meteorite to meteorite, which suggests hydrothermal transport on a kilometer scale. The remaining elements vary from sample to sample, suggesting transport on a centimeter scale.There is no conclusive evidence for nebular fractionation affecting C1 's. Though C1 chondrites have lower $\text{Zr}\text{Hf}$ and $\text{Ir}\text{Re}$ ratios than do other chondrite classes, these ratios vary in other classes, suggesting that those classes rather than C1's are fractionated. Three fractionation-prone REE—Ce, Eu, and Yb have essentially the same relative abundances in C1's and all other chondrite classes, and hence apparently are not fractionated in C1's. We did not confirm the large Tb and Yb variations in C1's reported by other workers.We present revised mean C1 abundances for 35 elements, based on the new data and a critical selection of literature data. Changes are generally less than 10%, except for Br, Rb, Ag, Sb, Te, Au, and the REE.The Plainview C2 xenolith has normal trace element abundances, except for 3 elements falling appreciably above the C2 range: Rb, Cs, and Bi. Hydrothermal alteration may be the reason for all 3, though nebular fractionation remains a possibility for Bi.     

Accretionary rims on inclusions in the Allende meteorite

Many inclusions in Allende, particularly those with irregular shapes, are surrounded by a sequence of thin layers which differ from one another in texture, mineralogy and mineral-chemistry. The layer underlying all others contains either: IA, pyroxene needles + olivine + clumps of hedenbergite and andradite; IB, olivine doughnuts; or IC, rectangular olivine crystals. The next layer outward, II, contains tiny (<5 μm) olivine plates and Layer III large (5–10 μm) olivine laths. The final layer, IV, occurs as clumps of andradite + hedenbergite surrounded by magnesium-rich pyroxene needles. It separates Layer III from the Allende matrix which is more poorly sorted and more sulfide-rich than Layer III. Nepheline and iron sulfide are common constituents of most layers, the latter being particularly fine-grained and abundant in Layer II. Although not every layer is present on every inclusion, the sequence of layers is constant. Evidence that the rims are accretionary aggregates includes the presence of highly disequilibrium mineral assemblages and the fact that they are highly porous masses consisting of many euhedral crystals with few intergrowths. In addition, the layers are thickest in topographic hollows on the surfaces of inclusions and the inner layers are absent or discontinuous beyond such irregularities, suggesting that the probability of accretion of crystals was low initially, except in pockets, and became greater later, after a soft cushion of accreted condensate crystals had already formed. Separation of assemblages of different mineralogy, mineral-chemistry and texture into different rim layers seems best explained by nebular models in which long, slow cooling histories allow differentiation during condensation by grain/gas separation processes.     

Spring-dashpot-mass models for foundation vibrations

The foundation on deformable soil, which, in general, radiates energy, can be represented in structural dynamics as a simple spring-dashpot-mass model with frequency-independent coefficients. For the two limiting cases of a site, the homogeneous half-space and the homogeneous layer fixed at its base, the coefficients are specified in tables for varying parameters such as ratios of dimensions and Poisson's ratio. Rigid foundations on the surface and with embedment are considered for all translational and rotational motions. In a practical analysis of soil–structure interaction this dynamic model of the foundation is coupled directly to that of the structure, whereby a standard dynamics program is used. © 1997 by John Wiley & Sons, Ltd.     

The effect of urbanization in an arid region: Formation of a perched water table that causes environmental damages

Construction in a new neighborhood in the israeli town of Dimona, situated in an arid region in the south of the country (150 mm average annual rainfall), resulted in a rise in groundwater levels during the subsequent rainy seasons This caused flooding of shelter basements, soil sliding, and sagging which permanently damaged walls and buildings The neighborhood had been built on continental sands and marls blanketed by loess, on a valley slope near a rocky anticlinal dip-slope Subsurface studies, using piezometer holes and groundwater analyses, revealed the presence of sand lenses alternating with plastic marls, which act as seasonal aquifers with perched water tables Groundwaters obtain high SO ₄ ⁻² and Cl⁻ corrosivity through contact with these nonflushed marls of the Neogene valley fill (Hazeva Formation) The reasons for the rising of groundwater were found to be (a) artificial interference with the natural (pre-construction) drainage system—interception of the hillside runoff by building plots, roads, etc, (b) partial denudation of the loess blanket, increasing the local infiltration and the build-up of local, perched water tables, and (c) corrosion of concrete and steel pipelines, as well as foundations, by prolonged contact with corrosive groundwater, resulting in haphazard but massive leakage Guidelines are proposed for an environmental improvement plan, which would include terracing and planting of the watershed above town to increase evapotranspiration, lowering of the water table by pumping, and diverting the water to suburban parks (groves of saltresistant trees), and replacement of steel and cement pipes by a non-corrodable plastic pipe system