Earthquake breakdown energy scaling despite constant fracture energy.
Earthquake breakdown energy scaling despite constant fracture energy.
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DOI：
10.1038/s41467-022-28647-4
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发表时间：
2022-02-22
影响因子：
16.6
通讯作者：
Kammer DS
中科院分区：
文献类型：
--
作者：
Ke CY;McLaskey GC;Kammer DS
为了确定控制地震力学的断层弱化过程，通常从地震测量中推断地震破裂能量。观察到击穿能量与滑移成比例，这通常归因于增强的故障弱化与持续滑移或高滑移率，可能是由闪速加热和热加压引起的。然而，地震学推断的击穿能量变化超过六个数量级，并经常被发现是负值。这使人们对通常的解释产生了怀疑，即击穿能是断裂能的代理，断裂能是一种必须是正值的材料属性，通常被观察到与尺度无关。在这里，我们提出了一个动态模型，表明击穿能量缩放可以发生，尽管恒定的断裂能量，并不需要热加压或其他增强削弱。相反，地震破裂能量标度仅仅是由于尺度不变的应力降过冲而发生的，这可能更直接地受到整体破裂模式（裂纹状或脉冲状）的影响，而不是来自特定的滑动弱化关系。地震破裂能通常被解释为断裂能的代表，但被观察到与震级成比例。在这里，作者表明，一个规模独立的应力过冲，在3D动态地震破裂模拟中看到的，导致可比的缩放，尽管恒定的断层断裂能量。
In the quest to determine fault weakening processes that govern earthquake mechanics, it is common to infer the earthquake breakdown energy from seismological measurements. Breakdown energy is observed to scale with slip, which is often attributed to enhanced fault weakening with continued slip or at high slip rates, possibly caused by flash heating and thermal pressurization. However, seismologically inferred breakdown energy varies by more than six orders of magnitude and is frequently found to be negative-valued. This casts doubts about the common interpretation that breakdown energy is a proxy for the fracture energy, a material property which must be positive-valued and is generally observed to be relatively scale independent. Here, we present a dynamic model that demonstrates that breakdown energy scaling can occur despite constant fracture energy and does not require thermal pressurization or other enhanced weakening. Instead, earthquake breakdown energy scaling occurs simply due to scale-invariant stress drop overshoot, which may be affected more directly by the overall rupture mode – crack-like or pulse-like – rather than from a specific slip-weakening relationship. Earthquake breakdown energy is commonly interpreted as a proxy for fracture energy but is observed to scale with magnitude. Here the authors show that a scale-independent stress overshoot, as seen in the 3D dynamic earthquake rupture simulations, leads to comparable scaling despite constant fault fracture energy.
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影响因子：
3.9
作者：
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通讯作者：
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影响因子：
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DOI：
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