Wikipedia names thermal monitoring as one of the methods for predicting volcanic eruptions. I was able to find some papers (First, Second) on such thermometry and while they are challenging (I retired from physics years ago), I will consult them for the methods.
What I completely fail to find information on, is how current thermal behavior is supposed to be linked to future eruptions (other than: "it’s getting hotter, that could be magma rising upwards"). I realize we don’t have complete theories, but I hope you can tell me what kinds of ansatzes there are.