Geophysical constants

Certainly, the system of equations for the attraction field is much more complicated than that for the potential. Before we continue it may be appropriate to make the following comment. In all geophysical methods the fields, such as the particle displacement caused by elastic waves, the constant and time-varying electric... 

Newsom HE (1995) Composition of the solar system, planets, meteorites, and major terrestrial reservoirs. In Global Earth Physics. A handbook of physical constants. Ahrens TJ (ed) American Geophysical Union, Washington, 159-189... 

Anderson O. L. (1972). Patterns in elastic constants of minerals important to geophysics. In Nature of the Solid Earth, E. C. Robinson, ed. New York McGraw-Hill. 

In this connection, the members of this Section could do a service to the other Sections by making clearer the real meaning of some of the physical concepts and physical constants involved in geophysical problems. For instance, much confusion has been caused by the fact that there is more than one kind of rigidity . The geologist to whom the statement that the earth has the rigidity of steel is rather vague may take temporary comfort from the fact that the statement also needs much qualification and explanation to the physicist. ... 

Figure 6.10. Accumulation of C in non-steady-state soils of a mature black spruce/moss forest in central Manitoba, Canada. Data shown are (A) for sphagnum moss that has accumulated since the site last burned (-100 yr before sampling), and (B) for the humus and charred layer below the regrowing moss and including the A horizon. The soil is developed on the sediments of a lake that dried up -7000 years ago. The parameters 7 = plant input (kgCuf2yr ) and k = decomposition constant (yr-1). Reprinted from Trumbore and Harden (1997), with permission from the American Geophysical Union.

Elastic constants of minerals are the key to understanding geophysical properties of the Earth s interior. Bulk modulus and rigidity parameters, for example, influence the velocities of seismic waves through the Earth. Numerous experi-... 

This method has a number of powerful features. First, it is very fast. Thus, one can calculate many structures and also study the effects of pressure and temperature upon the structures. Structures of low symmetry can be considered if covalency effects are small, so as to obtain a full set of elastic constants. Indeed, the most important applications of this method within geophysics have been in evaluating equations of state (volume as function of pressure and/or temperature) and elastic constants that can be related to seismic velocities. 

Yoder C. F. (1995) Astrometric and geodetic properties of Earth and the solar system. laAGU Reference Shelf 1 Global Earth Physics, A Handbook of Physical Constants (ed. T. J. Ahrens). American Geophysical Union, Washington, DC, pp. 1-31. 

Figure 16 Distribution of calculated advective water ages (kyr) in the system. Water age contours correspond to constant variations of 10 yr between 0 Myr and 0.1 Myr and variations of 10 yr for time periods varying between 0.1 Myr and 1 Myr, each one of these intervals being represented by a different color, from the youngest (dark blue) to the oldest (red), which corresponds to ages higher than IMyr (Castro and Gohlet, 2003) (reproduced hy permission of American Geophysical Union from Water Resour. Res. 2003, 39, 1172).

A random process is weakly stationary if its mean value and autocorrelation function are independent of r. Thus, for a weakly stationary random process, the mean value is a constant [fJiy r) = fiy] and the autocorrelation function depends only on the spatial lag 6 [e.g., Ryir, r + 6) = Ry d)]. A random process is strongly stationary if the infinite collection of higher order statistical moments and joint moments are space invariant. Most geophysical phenomena are not strongly stationary. However, the random process under study must be at least weakly stationary, otherwise the results of the space- or time-series analysis can be suspect. An extensive treatment of these statistical concepts is available 45, 46). A detailed re-... 

The nearly constant hysteresis width is important because it means that, at least in CdSe, the size-dependence of the hysteresis width is not sensitive to the kinetics. The upstroke transition pressure can nevertheless shift with nanocrystal size due to thermodynamic effects, as discussed earlier in this chapter (see SURFACE EFFECTS... above). Some geophysically-relevant systems may not exhibit full hysteresis loops because the high-pressure phase remains metastable as the pressure is released. Thus, special care should be taken to consider both the thermodynamics and kinetics in interpreting hysteresis measurements on such systems. 

Blackman, D. K., Wenk, H.-R. Kendall, J.-M. 2002. Seismic anisotropy of the upper mantle 1. Factors that affect mineral texture and effective elastic constants. Geochemistry, Geophysics, Geosystems, (in press). 

DeMore WB. 1992. Relative rate constants for the reactions of OH with methane and methyl chloroform. Geophysical Research Letters 19 1367-1370. 

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