Intuitive understanding of slow earthquakes using model experiments

在孕震带下方可以观察到缓慢的地震。构成地球的岩石经常被建模为麦克斯韦流体，只有当它在与松弛时间尺度相比足够短的时间尺度上变形时，它才具有弹性行为。然而，随着这些脆性/韧性和弹性/粘性转变，地震活动如何变化仍不清楚。在这里，我们用准麦克斯韦流体在不同应变率下进行了剪切变形实验，结果表明，相同的材料既可以引起与弹性回弹有关的地震，也可以引起与粘性流动有关的地震。在阈值附近，破裂以剪切波速度传播的地震和粘性松弛同时发生。

Slow earthquakes are observed beneath the seismogenic zone. The rock consisting the Earth is frequently modeled as a Maxwell fluid which behaves elastically only when it deforms at a time scale which is sufficiently short compared to the relaxation time scale. However, it still remains unclear how the seismicity changes with these brittle/ductile and elastic/viscous transition. Here, we perform shear deformation experiments using quasi-Maxwell fluid under different strain rates, and show that the same material can cause earthquakes associated with elastic rebound as well as viscous flow. Around the threshold, both earthquakes in which ruptures propagate at a shear wave velocity and viscous relaxation occur simultaneously.