Showing papers in "Physics of the Earth and Planetary Interiors in 1994"

TL;DR: In this article, the authors present ternary and quaternary phase diagrams to provide constraints on the nature of the light elements in the outer core of the Earth's core.

TL;DR: In this article, it was shown that the isothermal remanent magnetisation (IRM) acquired by natural mineral assemblages closely conforms to a cumulative log gaussian (CLG) function of the magnetising field.

TL;DR: In this paper, the authors show that the presence of H2O drastically changes melting temperature, liquidus phases and the coexisting melt composition in the Mg2SiO4H2O system.

TL;DR: In this article, the authors used a Fisherian distribution characteristic of paleosecular variation (PSV) and a uniform distribution representing transitional data resulting from reversals and excursions of the geomagnetic field to determine the most precise value of the angular standard deviation (ASD) characteristic of PSV.

TL;DR: In this article, the authors evaluated the depth to which metastable olivine (α) can survive in a subduction zone and the depth interval over which transformation to β- or γ-(Mg,Fe)2SiO4 occurs.

TL;DR: In this paper, a combination of X-ray diffraction during heating cycles and Raman spectroscopy on recovered samples was determined under which the P - V - T behavior of the perovskite remains reversible.

TL;DR: In this paper, the Earth's main magnetic field can be described as a two-scale process, and the stationary isotropic statistical model described describes the behaviour of the field in statistical terms.

TL;DR: In this article, the effects of rotation and a solid inner core on high Reynolds number buoyancy-driven flow in a fluid with the geometry of the Earth's liquid outer core were determined.

TL;DR: In this paper, the authors discuss two methods that quantify the contribution of different groups to the AMS: (1) comparative measurements of the magnetic susceptibility in low fields and high fields and (2) heating curves from 77 K to room temperature (low temperature magnetic susceptibility, LTMS).

TL;DR: A detailed geometry of the Wadati-Benioff zone under Costa Rica, obtained from seismicity recorded by a dense local seismographic network jointly operated by the Costa Rica Volcanological and Seismological Observatory, National University, and the Charles F. Richter Seismology Laboratory, University of California, Santa Cruz, was presented in this article.

TL;DR: In this article, the effect of the saturation of moment-magnitude relationships caused by source finiteness was investigated, and it was shown that a value of unity can be expected only in a range of earthquake sizes where the relevant magnitude has already started to saturate.

TL;DR: In this article, two simple models involving either lines or planes of interacting spherical particles are used to show that non-uniform distributions of spherical particles can give rise to large anisotropies.

TL;DR: In this paper, single crystals of MgSiO3 in the perovskite structure have been grown at a peak pressure of 26 GPa and temperature of ∼ 1600 K using a 2000 ton uniaxial split-sphere high-pressure apparatus (USSA-2000).

TL;DR: In this paper, the authors presented the complete directional archaeomagnetic data at present available for France from backed clay found in situ, and used Bivariate statistics to draw the curves of the variation of the direction of the terrestrial magnetic field (TMF) for Paris during the last 21 centuries.

TL;DR: In this paper, the decay of coda wave amplitude was analyzed by using the single isotropic scattering model to determine coda Q,Qc, in Western Anatolia (Turkey).

TL;DR: In this paper, the authors evaluated the chemical composition of the lower mantle and concluded that compositional change is not the cause of resistance to slab penetration, and the proposal that a large increase of viscosity at the 660 km discontinuity impedes descending slabs is also rejected.

TL;DR: In this article, the phase velocities of Rayleigh waves along 400 well-distributed paths are obtained in the period range 60-300 s, by fitting the data with synthetic seismograms computed with known source parameters in a reference earth model represented by the Preliminary Reference Earth Model.

TL;DR: In this article, the influence of early diagenesis on the natural remanent magnetisation (NRM) in sediments from the Calabrian ridge (Central Mediterranean) is analyzed with the help of fuzzy c-means (FCM) cluster analysis and nonlinear mapping (NLM).

TL;DR: In this article, the effects of increasing vigor of convection, internal heating and extremely negative Clapeyron slope of the spinel-perovskite phase transition were investigated in a 5 × 5 × 1 configuration.

TL;DR: In this paper, a method based on the Langer approximation and on perturbation theory is developed to model Sd waves in the presence of anisotropy in D″.

TL;DR: In this paper, the effect of non-deformable inclusions on the frequency-dependent rheology of a rhyolite melt plus crystals has been investigated using a sinusoidal torsion deformation device for measurements of shear viscosity and modulus in the frequency range of 5 mHz to 20 Hz at temperatures of 750-1050°C.

TL;DR: In this article, the effects of depth-dependent thermal expansivity, viscosity and thermal conductivity on mantle convection with phase transitions have been examined with two-dimensional finite-element simulations in an aspect-ratio four ☐.

TL;DR: In this article, the authors calculate density and seismic velocities of mineral assemblages of (Mg, Fe)SiO_3 perovskite and (mg,Fe)O magnesiowustite at lower-mantle pressures and temperatures.

TL;DR: In this paper, the digital seismic data recorded by a telemetered seismic array has been used to compute seismic moments and stress drops of local earthquakes in the Garhwal Himalaya region based on Brune's model of the earthquake source.

TL;DR: The seismic data recorded during the French Pilot Experiment OFM-SISMOBS (Observatoire Fond de Mer) were carefully analyzed as discussed by the authors, which was successfully conducted between 28 April and 11 May 1992 Notwithstanding the technical goal of the experiment, which was to show the feasibility of installing and recovering two sets of three-component broadband seismometers (one inside an Ocean Drilling Program (ODP) borehole and another inside an ocean-bottom seismograph (OBS) sphere in the vicinity of the hole), the second goal was to obtain for the first time

TL;DR: In this paper, a tomographic inversion of Rayleigh and Love wave velocities was used to obtain group velocity maps of East Asia (60-140°E and 20-60°N).

TL;DR: In this paper, the stability of diopside perovskite at conditions of 16-19 GPa and 1250-1900°C was determined using a 6-8 type multi-anvil apparatus.

TL;DR: In this paper, the effects of different topographies on the time delays, amplitudes, and waveforms of the direct P wave as well as on the P660s converted wave were quantified by applying a Kirchhoff-Helmholtz integration over the wave fields at the 660 km discontinuity interface.

TL;DR: In this paper, a new data bank was built which contains only those 211 stations where rigid control of every step in the observations, calibrations and reduction could be made either because the original data are stored in the World Data Center C, or because the published results give enough information to permit checks and revisions.

TL;DR: The pressure dependence of the elastic wave velocities for a polycrystalline specimen (100% theoretical density of majorite-pyrope garnet) has been determined at room temperature to 3 GPa by ultrasonic phase comparison interferometry as mentioned in this paper.