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.在地壳中，弹性应力会在坚硬岩体与较弱的断层或断裂带之间重新分布，并在大地震后通过非弹性形变随时间逐渐松弛。恒定应变边界为余震场景下的自组织与热力学平衡研究提供了理想的研究框架。为探究不同地壳深度下脆性破裂引发的震后形变，我们针对白云石大理岩开展了围压范围为2至70 MPa的多级应力斜坡松弛实验。我们采用分布式光纤传感（Distributed Optical Fiber Sensing）对试样表面进行实时全场应变测量（Miao等人，2025），据此约束了应变分布，并绘制了松弛前后高应变事件的空间分布模式。