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Thermal and electrical conductivity of iron at Earth’s core conditions
New estimates indicate that the adiabatic heat flux is 15 to 16 terawatts at the CMB, higher than present estimates of CMB heat flux based on mantle convection; the top of the coremust be thermally stratified and any convection in the upper core must be driven by chemical convection against the adverse thermal buoyancy or lateral variations in CMBHeat flow. Expand
Seismology and Plate Tectonics
1. Introduction 2. Mechanisms of elastic media 3. Elastic waves in simple media 4. Earth structure and earthquake location 5. Free oscillations 6. The seismic source 7. Plate tectonic theory AppendixExpand
On the resolution of density within the Earth
Roughly 30 years have passed since the last publication of a linear resolution calculation of density inside the Earth. Since that time, the data set of free oscillation degnerate frequencies hasExpand
Geomagnetic secular variation
We analyse over 175000 magnetic observations from an interval spanning 1695-1980 to produce a sequence of maps of the magnetic field at the core-mantle boundary; we find that even the earlier dataExpand
The influence of potassium on core and geodynamo evolution
We model the thermal evolution of the core and mantle using a parametrized convection scheme, and calculate the entropy available to drive the geodynamo as a function of time. The cooling of the coreExpand
Can the Earth's dynamo run on heat alone?
SUMMARY The power required to drive the geodynamo places significant constraints on the heat passing across the core‐mantle boundary and the Earth’s thermal history. Calculations to date have beenExpand
Mechanism for geomagnetic polarity reversals
Recent studies of old magnetic observations1 and the seismic velocity of the lower mantle2 suggest that at least part of the geomagnetic secular variation is driven by temperature anomalies in theExpand
Fall in Earth's Magnetic Field Is Erratic
It was found that magnetic field strength was nearly constant throughout this time, in contrast to the later period, which saw a fall in strength in patches of reverse magnetic flux in the Southern Hemisphere. Expand
Gross thermodynamics of two-component core convection
We model the inner core by an alloy of iron and 8 per cent sulphur or silicon and the outer core by the same mix with an additional 8 per cent oxygen. This composition matches the densities ofExpand
The secular variation of Earth's magnetic field
Models of the magnetic field at the core–mantle boundary at selected epochs from 1715.0 to 1980.0 reveal novel features in the field at the core. These suggest that the flow of core fluid is coupledExpand