The title of my research project is "probing the micromechanics of small magnitude earthquake slip", i.e. "how hot do faults get", within the framework of the DEEPNL research program (DEEPNL). In this project, I aim to determine how much temperature rise and weakening occur for small slip events, especially for the induced seismicities in the Groningen area. To do this, I combine friction experiments with numeircal discrete element method (DEM) to explore how strain localizes in fault guoges and the effecf of multi-phase fluids on heat generation at grain contacts. For friction experiments, they include direct shear experiments with triaxial vessels at low slip velocities (nm/s to mm/s) and slip-pulse experiments with rotary-shear apparatus at high slip velocities (up to m/s). With these, we could gain better understanding of the processes that govern the breakdown of friction which controls the maximum slip and maximum magitude of earthquakes. In addition, the physical parameters of earthquakes can be obtained and applied for fault rupture models of small earthquakes.