Confidence limits for silicate perovskite equations of state

We examine thermoelastic equations of state for silicate perovskite based on data from recent static compression studies. We analyze trade-offs among the fitting parameters and examine data sets for possible effects of metastability and of Mg-Fe solid solution. Significant differences are found between equations of state based on low pressure measurements obtained for perovskite outside of its stability field. Increasingly consistent results are obtained when higher pressure data are used, despite differences in the zero-pressure parameters used to describe the equations of state. The results highlight the importance of measuring the thermoelastic properties of perovskite at high pressure, specifically within its stability field, and the potential problems associated with large extrapolations of equations of state in the analysis of seismic data.