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Elastic Properties of the Magnesium Orthosilicate (Mg2SiO4) in Earth’s Upper Mantle

Seema Gupta and Amit Kumar Agrawal

ABSTRACT

Elastic properties of the low-pressure structure of the magnesium orthosilicate Mg2SiO4, (forsterite) are determined using a thermo dynamical method for the pressure range (0-24GPa). The geologically important quantities: second order elastic constants (SOE) and seismic wave velocity (Vp& Vs) are computed with the help of derived theory. The computed values of bulk moduli (B), and its pressure derivative (B?) of Mg2SiO4in i.e. forsterite is tested by analyzing the compression in volume with increase of pressure with the help of phenomenological theory and other based on ab-initio molecular dynamic simulation equation of states (EOS). The results of Cij agree well with the available experimental data in case of Mg2SiO4 (forsterite). Therefore, the results for the Mg2SiO4 (forsterite) may be important in geophysical study of these solids in earth?s upper mantle. 

Keywords: Elasticity; Forsterite; High pressure; ab-initio, EOS.