Delayed Microcracking as a Mechanism for Transient Relaxation Deformation in Upper Crustal Dolomite Marble

In the crust, elastic stress is redistributed between strong rock masses and weaker faults or fracture zones, gradually relaxing over time through inelastic deformation following major earthquakes. Constant strain boundaries provide an ideal framework for investigating self-organization and thermodynamic equilibration in aftershock scenarios. To investigate postseismic deformation resulting from brittle failure at different crustal depths, we conducted multi-stage stress ramp-relaxation experiments on dolomitic marble under confining pressures ranging from 2 to 70 MPa. Using Distributed Optical Fiber Sensing to provide real-time, full-field strain measurements at the sample surface (Miao et al. 2025), we constrained the strain distribution and mapped the spatial patterns of high-strain events before and after relaxation.