Is COMSOL Multiphysics good for subduction CFD modelling? Are there alternatives?
numerical modelling is a vast field and the tool to address your problem depends strongly on ... your problem and your approach!
Are you a master student? a PhD student with very short time to wrap up your thesis? A plumber with an intelectual interest in plate tectonics?
In short: Comsol may be an adequate tool. However, with large displacements (larger than the element volumes), you may want to avoid Finite Element method and probably better to have a look at other methods.
You can find a nice description of alternative methods in the book &quot;Introduction to Numerical Geodynamic Modelling&quot; from Professor Taras Gerya. He sugests to use Matlab, but you can probably follow all the book simply with Python.