Pulse-like, crack-like, and supershear earthquake ruptures with shear strain localization
Pulse-like, crack-like, and supershear earthquake ruptures with shear strain localization
复制标题
具有剪切应变局部化的脉冲状、裂缝状和超剪切地震破裂
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
J. Carlson
中科院分区：
文献类型：
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作者：
E. Daub;M. Manning;J. Carlson
[1]我们将剪切应变局部化到自发的弹性动力学破裂模拟使用剪切转换区（STZ）摩擦法。在STZ模型中，粒状断层泥中的塑性应变发生在称为STZ的局部区域。STZ的数密度由有效无序温度控制，并且有效温度升高的区域具有增加的应变速率。STZ理论解决了有效温度在整个断裂带宽度上的动态演化。由于反馈放大了初始有效温度的不均匀性，模型中自发形成剪切带。在动态地震模拟中，应变局部化是动态断层弱化的一种机制。剪切带的动态形成，降低了滑动应力，并减少了摩擦能量耗散的故障。我们研究了由于局部化引起的动态弱化在产生脉冲状、裂纹状和超剪切破裂中的作用。我们的研究结果表明，额外的削弱和减少的故障能量耗散由于本地化有显着的影响所需的初始剪切应力的超剪切或脉冲状破裂传播的故障。
[1] We incorporate shear strain localization into spontaneous elastodynamic rupture simulations using a shear transformation zone (STZ) friction law. In the STZ model, plastic strain in the granular fault gouge occurs in local regions called STZs. The number density of STZs is governed by an effective disorder temperature, and regions with elevated effective temperature have an increased strain rate. STZ theory resolves the dynamic evolution of the effective temperature across the width of the fault zone. Shear bands spontaneously form in the model due to feedbacks amplifying heterogeneities in the initial effective temperature. In dynamic earthquake simulations, strain localization is a mechanism for dynamic fault weakening. A shear band dynamically forms, reduces the sliding stress, and decreases the frictional energy dissipation on the fault. We investigate the effect of the dynamic weakening due to localization in generating pulse-like, crack-like, and supershear rupture. Our results illustrate that the additional weakening and reduction of on-fault energy dissipation due to localization have a significant impact on the initial shear stress required for supershear or pulse-like rupture to propagate on a fault.