Precipitation episodes in the upper Colorado River basin     

Herbert Riehl  Russell L. Elsberry 《Pure and Applied Geophysics》1964,57(1):213-220

Summary We wish to learn whether annual precipitation over the Colorado watershed is determined by occurrence or non-occurrence of a few large storms; or by other controls such as variations in frequency of minor disturbances. It is found that there is a semi-constant noise level of about six inches precipitation per year, composed of small rains. Occasional very large storms do contribute to rank order of annual precipitation over the available data sample which covers the period 1930–1960. However, most contribution to the rank order is derived from medium-sized storms yielding 0.3–1.2 inches of precipitation over the basin. Since storm yield depends mainly on duration rather than on precipitation intensity per day, a good correlation exists between annual precipitation and the number of days with precipitation above a certain threshold.  相似文献   

Forced wave motion in an unbouded space surrounding a lined,spherical cavity     

Herbert Reismann  John Gideon 《Pure and Applied Geophysics》1971,85(1):189-213

Summary This investigation considers the point-symmetric response of an unbounded, elastic medium. A spherical cavity in the unbounded medium is lined by an elastic, spherical shell attached to the surrounding medium. The shell liner is subjected to specified time-varying surface stress acting upon its internal surface. A detailed evaluation of the shell liner shielding characteristics is presented.  相似文献   

High-Capacity Wells for Conjunctive Use of Water     

Herbert H. Ham 《Ground water》1971,9(5):4-11

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Discussion of Designing Pumped Well Characteristics into Electric Analog Models by T. A. Prickett - October, 1967     

R. Herbert  Ph. D.  Isaac K. Chan 《Ground water》1968,6(4):40-40

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Tourism and society in four Austrian alpine communities     

Herbert G. Kariel 《GeoJournal》1993,31(4):449-456

Tourism has had profound impacts on Alpine communities. Changes in the inhabitants' way of life in their quest for a financially more rewarding pursuit are reviewed and residents' attitudes in four Austrian alpine communities regarding changes in family life, community welfare, community growth, and the environment are examined. The current situation regarding the importance of economic considerations and continued growth, as opposed to non-economic values, environmental considerations, and intangible elements, such as community well-being and the sociability of people, is analyzed against the backdrop of societal changes and characteristics of these communities.  相似文献   

A metal particle from a Ca,Al-rich inclusion from the meteorite Allende,and the condensation of refractory siderophile elements     

Herbert Palme  Frank Wlotzka 《Earth and Planetary Science Letters》1976,33(1):45-60

A small particle (ca. 10^?6 g) was magnetically separated from a Ca,Al-rich inclusion of the Allende meteorite. By using instrumental neutron activation analysis it was found that the elements Os, W, Re, Ir, Mo, Ru and Pt were enriched by a mean factor of about 7000 relative to Cl chondrites.A polished section of the grain showed that it consisted mainly of silicates, with a rounded particle of metal and sulfide (20 μm across) attached to it.Concentrations of up to 11% Pt were determined with the microprobe in the Ni-Fe center of the particle. Furthermore, Rh was for the first time measured in an Allende inclusion. It is enriched in about the same degree as Pt, Ir and W. The Ni-Fe center was surrounded by troilite. Mo was concentrated in the sulfide, while Os and Ru were inhomogeneously distributed over the metal + sulfide phases. The particle is interpreted as direct product of metal condensation of the solar nebula. The sulfide phase formed at lower temperatures and caused redistribution of the refractory siderophile elements. Condensation calculations for a metal alloy show that Fe and Ni are expected to be already present at higher temperatures than the condensation temperatures of pure Fe. Pt and Rh, having lower condensation temperatures than pure Fe should also be completely condensed above the condensation temperature of pure Fe. Kinetic considerations show that minimum times to grow this kind of particle should be of the order of 500 years at 10^?3 atm.  相似文献   

The fluid dynamics of a basaltic magma chamber replenished by influx of hot,dense ultrabasic magma     

Herbert E. Huppert  R. Stephen J. Sparks 《Contributions to Mineralogy and Petrology》1981,75(3):279-289

This paper describes a fluid dynamical investigation of the influx of hot, dense ultrabasic magma into a reservoir containing lighter, fractionated basaltic magma. This situation is compared with that which develops when hot salty water is introduced under cold fresh water. Theoretical and empirical models for salt/water systems are adapted to develop a model for magmatic systems. A feature of the model is that the ultrabasic melt does not immediately mix with the basalt, but spreads out over the floor of the chamber, forming an independent layer. A non-turbulent interface forms between this layer and the overlying magma layer across which heat and mass are transferred by the process of molecular diffusion. Both layers convect vigorously as heat is transferred to the upper layer at a rate which greatly exceeds the heat lost to the surrounding country rock. The convection continues until the two layers have almost the same temperature. The compositions of the layers remain distinct due to the low diffusivity of mass compared to heat. The temperatures of the layers as functions of time and their cooling rate depend on their viscosities, their thermal properties, the density difference between the layers and their thicknesses. For a layer of ultrabasic melt (18% MgO) a few tens of metres thick at the base of a basaltic (10% MgO) magma chamber a few kilometres thick, the temperature of the layers will become nearly identical over a period of between a few months and a few years. During this time the turbulent convective velocities in the ultrabasic layer are far larger than the settling velocity of olivines which crystallise within the layer during cooling. Olivines only settle after the two layers have nearly reached thermal equilibrium. At this stage residual basaltic melt segregates as the olivines sediment in the lower layer. Depending on its density, the released basalt can either mix convectively with the overlying basalt layer, or can continue as a separate layer. The model provides an explanation for large-scale cyclic layering in basic and ultrabasic intrusions. The model also suggests reasons for the restriction of erupted basaltic liquids to compositions with MgO<10% and the formation of some quench textures in layered igneous rocks.  相似文献   

Determination of Aquifer Parameters from Large-Diameter Dug Well Pumping Tests   总被引：1，自引：0，他引：1  

R. Herbert  R. Kitching 《Ground water》1981,19(6):593-599

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A laboratory model of a replenished magma chamber     

Herbert E. Huppert  J. Stewart Turner 《Earth and Planetary Science Letters》1981,54(1):144-152

It has recently been suggested that periodic influxes of hot but heavy magma into the base of a basaltic magma chamber can remain isolated from the rest of the chamber while the new magma cools and crystallization proceeds. When thermal equilibrium is almost complete, the suspended crystals settle out and the residual, less dense liquid can then mix with the fluid above. In the present paper the basic fluid-dynamical processes underlying this model have been investigated in laboratory experiments using aqueous solutions. The lower layer was hot KNO₃ solution, for which saturated solutions become less dense as the temperature decreases. With a cold, deeper layer of less dense NaNO₃ or K₂CO₃ above the lower layer, there was strong convective transfer of heat through a sharp interface separating the layers, at a rate which is predicted here drawing on previous studies carried out with oceanographic applications in mind. Once crystallization began, non-equilibrium effects became important and the observed temperatures differ somewhat from those predicted. In the experiments crystals grew mainly from the bottom rather than while in suspension, but this is not an essential aspect of the model. The important fact is that the density of the residual liquid in the lower layer decreased until it became equal to that of the upper layer, and then the interface broke down so that the two layers mixed thoroughly together, leaving a layer of KNO₃ crystals at the base. No crystallization at all occurred when the hot input liquid was forced to mix initially with the cold solution already in the chamber.  相似文献   

The cosmic abundance of molybdenum     

Herbert Palme  Werner Rammensee 《Earth and Planetary Science Letters》1981,55(3):356-362

Fifteen carbonaceous chondrites were analysed for Mo and Ir by neutron activation analysis combined with a metal extraction method. The results of two Orgueil analyses gave a mean concentration of 915 ppb Mo. This corresponds to 2.51 atoms Mo/10⁶ atoms Si, which is 50% lower than data reported by Case et al. [3]. The lower Mo concentration for Orgueil was predicted by Suess and Zeh [4] from semi-empirical abundance rules. A constant Mo/Ir ratio is found for C1, C2, and C3V chondrites; C3Os have variable Mo/Ir ratios. These variations are due to variable Ir concentrations. Micron-sized grains enriched in Ir but not in Mo are presumably responsible for these variations. The Mo content of Karoonda is nearly a factor of four lower than that of C3V chondrites.  相似文献