CNR-SPIN, Department of Physics, University of Naples "Federico II," Naples 80126, Italy.
Department of Mathematics and Physics, Second University of Naples and CNISM, Caserta 81100, Italy.
Phys Rev Lett. 2015 Sep 18;115(12):128001. doi: 10.1103/PhysRevLett.115.128001. Epub 2015 Sep 15.
The unexpected weakness of some faults has been attributed to the emergence of acoustic waves that promote failure by reducing the confining pressure through a mechanism known as acoustic fluidization, also proposed to explain earthquake remote triggering. Here we validate this mechanism via the numerical investigation of a granular fault model system. We find that the stick-slip dynamics is affected only by perturbations applied at a characteristic frequency corresponding to oscillations normal to the fault, leading to gradual dynamical weakening as failure is approaching. Acoustic waves at the same frequency spontaneously emerge at the onset of failure in the absence of perturbations, supporting the relevance of acoustic fluidization in earthquake triggering.
一些断层的意外弱化归因于声波的出现，这些声波通过一种被称为声流化的机制来促进失效，该机制也被提议来解释远距离地震触发。在这里，我们通过对颗粒断层模型系统的数值研究来验证该机制。我们发现，粘滑动力学仅受施加在与断层垂直的振荡的特征频率上的扰动的影响，从而导致随着失效的临近逐渐动态减弱。在没有扰动的情况下，在失效开始时会自发出现相同频率的声波，这支持了声流化在地震触发中的相关性。
