Showing papers in "Physics of the Earth and Planetary Interiors in 1975"

TL;DR: In this article, a set of three parametric earth models (PEM) are presented, where radial variations of the density and velocities are represented by piecewise continuous analytical functions of radius (polynomials of order not higher than the third).

TL;DR: In this article, the lower mantle and outer core of the PEM model are extrapolated to zero pressure using fourth-order finite-strain relations, and the results are compared with recent experimental data on relevant materials.

TL;DR: The feasibility of a precessionally driven dynamo is investigated in this paper, where the relative orientation of the angular-velocity vectors of the mantle and core and the precession vector of the earth are determined from a torque balance.

TL;DR: In this paper, the Vashchenko and Zubarev relationship for the Gruneisen ratio γ at any pressure was generalized to random three-dimensional motion, yielding the Dugdale-MacDonald expression for high-temperature thermal oscillations of atoms in simple crystal structures with purely central interatomic forces.

TL;DR: In this paper, the authors analyzed old seismograms of the Tungus event of June 30, 1908 and compared with contemporary records of air explosions from Novaya Zemlya and Lop-Nor.

TL;DR: In this paper, it was shown that if a spherical shell is magnetized in the direction of and proportional to a magnetic field of origin internal to the shell and the magnetizing field later disappears, no magnetic field exists external to a shell.

TL;DR: In this paper, a generalised secular equation for the Stoneley mode is derived and solved numerically, assuming that the interface of two loosely bonded half spaces permits a finite amount of slip, and that a simple linear relation exists between the prevailing shearing stress and the slip.

TL;DR: In this article, the pressure dependence of the three lattice parameters and unit cell volume of fayalite (Fe2SiO4 olivine) was determined by X-ray diffraction under hydrostatic pressures up to 70 kbar.

TL;DR: In this article, a single-station method for ten paths in the western Pacific was used to determine the phase velocities and upper-mantle structure of the Rayleigh wave.

TL;DR: In this article, the inversion of two-dimensional structures is still an almost uninvestigated area and only for very restricted anomalous domains exact methods exist: undulated interface between perfect conductor and insulator; thin non-uniform sheet.

TL;DR: In this article, it was shown that the amount of Fe that can be oxidized in the forsterite phase is directly related to the excess Si present, either incorporated in the structure, or available from another phase richer in SiO 2 such as pyroxene.

TL;DR: In this article, the important parameters governing electrical conductivity in minerals are discussed in terms of how they contribute to bulk conduction mechanisms within minerals; and how they pertain to the conditions of rocks in situ.

TL;DR: In this article, the authors measured the lattice parameters of β- and γ-Mg 2 SiO 4 at room temperature and at pressures up to 100 kbar using a multi-anvil high-pressure X-ray diffraction apparatus.

TL;DR: In this article, the lattice parameters of the perovskite phase of (Fe,Mg)TiO3 at room temperature and 1 bar are a 0 = 4.471 ± 0.004, b 0 = 5.753 −0.005, and c 0 = 7.429 ±0.006 A with 4 molecules per cell.

TL;DR: X-radiographic measurement of long-term growth rates for 89 colonies of the coral Montastrea annularis, collected over a 27.5−m depth range from St Croix, U.S. Virgin Islands, has established that M.annularis calcifies most rapidly at intermediate depths, and confirmed the identification of two distinct populations within this important frame-building species.

TL;DR: In this article, the results of a theoretical study of the interpretation of precursors to PP (Δ ∼ 100°) in terms of scattering by small-scale random irregularities in the crust and uppermost mantle are presented.

TL;DR: In this paper, the authors used short-period fundamental-mode Rayleigh waves (Rg) from records at Swedish seismograph network revealed their usefulness to elucidate both path and source properties.

TL;DR: In this article, the authors investigated the rupture process of the Tokachi-Oki earthquake (May 16, 1968) and that of the Kurile Islands earthquake (August 11, 1969) were investigated primarily on the basis of the long-period seismograms of WWSSN.

TL;DR: The top of the olivine-spinel phase change in subducted oceanic lithosphere can be located by the travel times of seismic waves which have propagated through the slab P-wave travel time residuals from deep earthquakes in the Tonga island are observed at Australian seismic stations are grouped according to the depth of the earthquake as mentioned in this paper.

TL;DR: Anomalies of electrical conductivity are considered in relation to other geophysical parameters, such as seismic wave velocity, attenuation, seismicity and density, and to tectonic features.

TL;DR: In this article, the average pole position at 3°S, 153°W, determined from six sites in these areas, is considered to reflect the average virtual pole position for the post-Sveconorwegian period of uplift and cooling (1120-975) · 106 year ago.

TL;DR: In this article, the large volume changes which accompany the phase transformations of rutile-cubic phase and perovskite oxides for TiO2 and (Fe,Mg)TiO3, respectively, contradict the shock data for similar phase transformations in SiO 2 and MgSiO3.

TL;DR: In this article, it was shown that high temperature may be a possible cause of such layers if we take into account that temperature amounts to 1,000°C at a depth of 40 km in the Japan and Philippine seas.

TL;DR: In this article, a set of fifteen 14-track tape-recording units were used along a profile from Darwin to Alice Springs in central Australia to determine upper-mantle travel times in Australia.

TL;DR: In this article, the amplitude and phase of the main tidal wave at Bruxelles have been compared with 15 gravimeters, static as well as astaticized, during periods not less than three months each.

TL;DR: In this paper, a basic inversion strategy for geophysical data is considered, and it is concluded that future progress depends on the use of synthetic data to resolve questions about the potential constraining power of GEMI data.

TL;DR: The morphology of slowly-varying geomagnetic external fields and the production mechanisms of electric current systems for those fields are briefly reviewed to provide background knowledge of the present state of research regarding the source fields for scientists concerned with the electromagnetic induction within the earth as mentioned in this paper.

TL;DR: In this paper, the behavior of time-varying electromagnetic fields near an island situated in a shallow ocean is investigated using both a three-dimensional finite-difference numerical method and a scaled analogue model method.

TL;DR: A magnetometer array study consists of a number of variometers recording simultaneously across a two-dimensional area as mentioned in this paper, and the observed response of the local structure is modelled numerically, taking the inducing field to be uniform.

TL;DR: In this article, the quality factor of the free oscillations of the earth is calculated from the observed time rate of decay of the energy of standing-wave patterns with time, and from the damping of travelling waves with distance, using the surface mantle waves recorded at a single I.P.G. long-period seismic station after each great circle path.