TEMSPOL: a MATLAB thermal model for deep subduction zones including major phase transformations

TEMSPOL is an open MATLAB code suitable for calculating temperature and lateral anomaly of density distributions in deep subduction zones, taking into account the olivine to spinel phase transformation in a self-consistent manner. The code solves, by means of a finite difference scheme, the heat transfer equation including adiabatic heating, radioactive heat generation, latent heat associated with phase changes and frictional heating. We show, with a few simulations, that TEMSPOL can be a useful tool for researchers studying seismic velocity, stress and seismicity distribution in deep subduction zones. Deep earthquakes in subducting slabs are thought to be caused by shear instabilities associated with the olivine to spinel phase transition in metastable olivine wedges. We investigate the kinematic and thermal conditions of the subducting plate that lead to the formation of metastable olivine wedges. Moreover, TEMSPOL calculates lateral anomalies of density within subducting slabs, which can be used to evaluate buoyancy forces that determine the dynamics of subduction and the stress distribution within the slab. We use TEMSPOL to evaluate the effects of heat sources such as shear heating and latent heat release, which are neglected in commonly used thermal models of subduction. We show that neglecting these heat sources can lead to significant overestimation of the depth reached by the metastable olivine wedge. (C) 2004 Elsevier Ltd. All rights reserved.