近日，以色列希伯来大学Fineberg Jay团队报道了对摩擦性破裂与地震成因和演化的研究。2025年1月8日出版的《自然》发表了这项成果。

据研究人员介绍，摩擦运动是由快速传播的破裂介导的，这些破裂将接触集合分离，在接触体之间形成摩擦界面。这些破裂类似于剪切裂缝。当这一过程发生在自然断层中时，这些快速破裂本质上就是地震。尽管断裂力学描述了这些单一物体的快速运动，但它们的成核过程尚不清楚。

研究人员通过扩展断裂力学来充分描述成核过程，以明确地包含有限的界面宽度（通常被忽略）。实验和理论证明，这种缓慢的稳定蠕变在一个明确的应力阈值下发生。此外，当缓慢的蠕动斑块接近界面宽度时，会发生拓扑转变，这些蠕动的斑块平滑地过渡到经典断裂力学所描述的快速断裂。

除了与断裂和材料强度相关外，这种破裂成核动力学的新图景与地震成核动力学直接相关，缓慢的地震破裂总是先于快速的地震破裂（只要界面上的初始缺陷定位在两个空间维度上）。这一理论可能为理解地震如何以及何时形成核，提供一个新的框架。

附：英文原文

Title: How frictional ruptures and earthquakes nucleate and evolve

Author: Gvirtzman, Shahar, Kammer, David S., Adda-Bedia, Mokhtar, Fineberg, Jay

Issue&Volume: 2025-01-08

Abstract: Frictional motion is mediated by rapidly propagating ruptures that detach the ensemble of contacts forming the frictional interface between contacting bodies. These ruptures are similar to shear cracks. When this process takes place in natural faults, these rapid ruptures are essentially earthquakes8,9. Although fracture mechanics describe the rapid motion of these singular objects, the nucleation process that creates them is not understood. Here we fully describe the nucleation process by extending fracture mechanics to explicitly incorporate finite interface widths (which are generally ignored). We show, experimentally and theoretically, that slow steady creep ensues at a well-defined stress threshold. Moreover, as slowly creeping patches approach the interface width, a topological transition takes place in which these creeping patches smoothly transition to the rapid fracture that is described by classical fracture mechanics. Apart from its relevance to fracture and material strength, this new picture of rupture nucleation dynamics is directly relevant to earthquake nucleation dynamics; slow, aseismic rupture must always precede rapid seismic rupture (so long as the initial defect in the interface is localized in both spatial dimensions). The theory may provide a new framework for understanding how and when earthquakes nucleate.

DOI: 10.1038/s41586-024-08287-y

Source: https://www.nature.com/articles/s41586-024-08287-y