Modelling Thermal Convection of Earth Mantle with Aspect Code

The study of mantle convection is one of the most important topics in geodynamics. Mantle convection causes the transfer of internal heat to the cold parts of the Earth, and the effects of this heat transfer are observed as the motion of tectonic plates on the Earth's surface. Earthquakes, volcanism, and mountain building at the plate margins result from the movement of tectonic plates. Although the mantle occupies a large volume of the Earth, there are many fundamental questions about mantle composition, rheology, dynamics, and history. Many of these questions remain unanswered due to our indirect observations of the mantle. A major tool to study mantle dynamics is numerically analyzing mantle convection equations. In this work, we used Aspect -short for Advanced Solver for Problems in Earth's Convection- code to simulate mantle convection. The geometric model used in the simulation is a box of 4200 km by 3000 km. Using this code, we investigated the effect of different Rayleigh numbers on controlling the mantle convection and creating mantle plumes. Results show that the number of mantle plumes increases with increasing Rayleigh number, and the rising mantle plumes become thinner with the Rayleigh number increasing. Finally, we studied the relationship between the Rayleigh number and the Nusselt number (surface heat flux). We conclude that there is a power-law relation between Rayleigh and Nusselt numbers.