Illien Luc, Turowski Jens M, Sens-Schönfelder Christoph, Berenfeld Clément, Hovius Niels
GFZ Helmholtz Centre for Geosciences, Potsdam, Germany.
Universität Potsdam, Department of Mathematics, Potsdam, Germany.
Nat Commun. 2025 Feb 20;16(1):1790. doi: 10.1038/s41467-025-57151-8.
Earthquakes introduce transient mechanical damage in the subsurface, which causes postseismic hazards and can take years to recover. This observation has been linked to relaxation, a phenomenon observed in a wide range of materials after straining perturbations, but systematic controls on the recovery duration in the shallow subsurface after earthquake ground shaking have not been determined. Here, we analyse the effects of two successive large earthquakes and their aftershocks on ground properties using estimates of seismic velocity from ambient noise interferometry. We show that the relaxation time scale is a constant that is an intrinsic property of the substrate, independent of the intensity of ground shaking. Our study highlights the predictability of earthquake damage dynamics in the shallow subsurface and also in other materials. This finding may be reconciled with existing state variable frameworks by considering the superposition of different populations of damaged contacts.
地震会在地下引入瞬态机械损伤，这会导致震后灾害，且恢复可能需要数年时间。这一观测结果与松弛现象有关，松弛是在各种材料受到应变扰动后观察到的一种现象，但尚未确定地震地面震动后浅层地下恢复持续时间的系统控制因素。在这里，我们使用基于环境噪声干涉测量法的地震速度估计值，分析了两次连续大地震及其余震对地面特性的影响。我们表明，松弛时间尺度是一个常数，是基底的固有属性，与地面震动强度无关。我们的研究突出了浅层地下以及其他材料中地震损伤动力学的可预测性。通过考虑不同受损接触群体的叠加，这一发现可能与现有的状态变量框架相协调。
