Prospecting for water in the transition zone: d ln(Vs)/d ln(Vp)

We report the values of R = d ln(Vs)/d ln(Vp) due to water as a function of pressure for Mg2SiO4 olivine, wadsleyite, ringwoodite. The results show that ringwoodite has significantly lower R than olivine and wadsleyite; due to the reason that bulk modulus of ringwoodite is more sensitive to water than shear modulus. R of ringwoodite decreases with pressure while R of olivine and wadsleyite increases with pressure. R reported here was calculated using theoretical method derived equation of states. R due to temperature is also reported as a comparison of R due to water. The local value of R in the upper mantle and transition zone can discriminate between lateral variations of water content and temperature as the origin of lateral seismic variations. Published by Elsevier B.V.