地球物理
In this paper we try to deduce the in situ stresses from the monopole acoustic waves of the well AIG10 between 689 and 1004 meters in depth (Corinth Golf). This borehole crosses competent sedimentary formations (mainly limestone), and the…
We report measurements of electric potentials at the surface of a spherical container of liquid sodium in which a magnetized inner core is differentially rotating. The azimuthal angular velocities inferred from these potentials reveal a…
Tiny basaltic samples containing finely grained titanomagnetite with Curie temperature less than 100 C were heated in air in weak field (25 to 100microT) at temperatures between 400 and 560 C for times as long as 32 hours. Oxyexsolution of…
In order to compare the ratios between the amplitudes of P and S acoustic waves drawn from various boreholes, we have defined a specific wave parameter called magnitude : for each shot, we have added the maximum positive amplitude values…
The method using the propagation of acoustic body waves within the stress modified areas around a vertical borehole has been applied to the granitic formation penetrated by the SAFOD Pilot hole near the San Andreas Fault trace. This method…
This paper shows that there are three types of shape of acoustic body waves propagating inside competent and homogeneous formations penetrated by a borehole : simple, double, and resonant. This fact is connected to the modifications…
A magneto-hydrodynamic model of boundary layers at the Core-Mantle Boundary (CMB) is derived and used to compute the viscous and electromagnetic torques generated by the Earth's nutation forcing. The predicted electromagnetic torque alone…
After describing all the contradictions associated with the current Plate Tectonics theory, this paper proposes a model where a single cause can explain all geophysical and geological phenomena. The source of the Earth's activity lies in…
Numerical models of the geodynamo are usually classified in two categories: those denominated dipolar modes, observed when the inertial term is small enough, and multipolar fluctuating dynamos, for stronger forcing. We show that a third…
We use a simple model of Bullard-type disc dynamo, in which the disc rotation rate is subject to harmonic oscillations, to analyze the generation of magnetic field by the parametric resonance mechanism. The problem is governed by a damped…
Dolomite crystals in partially dolomitized limestone from the Platteville Formation are both compositionally and microstructurally heterogeneous. A single dolomite crystal usually contains three phases: the host Ca-rich dolomite…
Nano-precipitates with tripled periodicity along the c-axis are observed in a Ca-rich dolomite sample from Proterozoic carbonate rocks with "molar tooth" structure. This observation is consistent with previous description of d reflections.…
Dehydration of water from surface Mg2+ is most likely the rate-limiting step in the dolomite growth at low temperature. Here, we investigate the role of polysaccharide in this step using classical molecular dynamics (MD) calculations. Free…
The key kinetic barrier to dolomite formation is related to the surface Mg2+-H2O complex, which hinders binding of surface Mg2+ ions to the CO3 2- ions in solution. It has been proposed that this reaction can be catalyzed by dissolved…
Vegetation characteristics providing spatial heterogeneity at the channel reach scale can produce complex flow patterns and the relationship between plant patterns morphology and flow resistance is still an open question (Nepf 2012). Unlike…
In this paper we present an approach for forecasting the imminent regional seismic activity by using geomagnetic data and Earth tide data. The time periods of seismic activity are the time periods around the Sun-Moon extreme of the diurnal…
This article presents a set of spectro-goniometric measurements of different water ice samples and the comparison with an approximated radiative transfer model. The experiments were done using the spectro-radiogoniometer described in…
Atomic clock technology is advancing rapidly, now reaching stabilities of $\Delta f/f \sim 10^{-18}$, which corresponds to resolving $1$ cm in equivalent geoid height over an integration timescale of about 7 hours. At this level of…
Seawater intrusion (SWI) is a complex process, where 3D modeling is often necessary in order to monitor and manage the affected aquifers. Here, we present a synthetic study to test a joint hydrogeophysical inversion approach aimed at…
A function for the bed-load sediment transport rate is derived. This is achieved from the first principle by using the entrainment probabilities of the sediment grains by rolling and lifting, and by introducing two travel lengths,…