Earth dons a different mantle

Article Abstract:

The earth's uppermost mantle contains peridotite which is a rock with 50-60% (Mg,Fe)2SiO4 olivine. Pressure variations in the transition zone induce transformation of olivine to spinel and perovskite-type crystal structures. These pressure-induced phase transitions of olivine increase the seismic wave velocities of the transition zone in the mantle at a depth of 410-660 kilo meters. There is disparity between the observed and the theoretically expected velocity jumps in the transition of olivine to beta spinel at a depth of 400 km.

Peridotite, Olivine

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Preparing for the worst

Article Abstract:

Scientists suggest that an international data bank of known nuclear explosive materials should be established in order to determine the source of nuclear materials following an explosion. The international database should include a database, a physical library of nuclear explosive materials and vetted procedures for handling both data and samples.

United States, General services, Explosives, Explosives Manufacturing, Company systems management, Information management, Materials, Nuclear facilities, Nuclear explosions

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Taking the earth's temperature

Article Abstract:

Research on the use of seismic tomography to study variations in the earth's interior temperature is discussed. The mantle's temperature cannot be measured directly, but variations in temperature affect seismic wave speeds.

Seismic tomography

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