The Road to the Rheology of the Earth's Materials

Rheological studies on the Earth's materials started in the 1970s following the establishment of the dislocation theory of metals, which occurred around the same time as the concept of global plate tectonics was proposed. Since then, many studies on the dislocation theory of oxides and halides and experimental and TEM investigations on dislocation structures have been carried out. The authors (S. Karato and M. Toriumi) began studies on the high-temperature dislocation annihilation of olivine, and later performed high-temperature and low-stress creep experiments on olivine single crystals from incubation to the third creep stage in a very large strain through steady state creep. A brief history is introduced of promising rheology research conducted by the authors' group during the period when the Earth's mantle rheology was established.