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了解控制断层摩擦的内在机制对于了解活动断层的孕震滑动十分关键。断层带中的位移常常局限在高反射(镜面)的滑动面上,通常滑动面上还覆盖有薄层的纳米颗粒状断层岩。本文展示了实验模拟的方解石断层中发育的镜面状滑动面,它由在室温条件下呈韧性的纳米颗粒链或是纳米纤维线性排列组成。这些微结构和相应的摩擦数据表明,断层滑动机制类似于经典的Ashby-Verrall超塑性,该机制能够产生不稳定的断层滑动。对这种机制而言,纳米晶体方解石断层泥中的扩散物质转移速度足够快,以致于可以控制石灰岩地区的孕震活动。随着壳内断层上越来越多地被证实存在着纳米颗粒状断层面,本文提出的机制很有可能普遍适用于壳内孕震活动。
Understanding the underlying mechanisms that control fault friction is crucial to understanding the seismic slip of active faults. Displacements in fault zones are often confined to highly reflective (specular) sliding surfaces, which are often also covered with thin layers of nanoparticle-like fault rocks. This article shows the experimental mirror-like sliding surface developed in an experimentally simulated calcite fault consisting of a linear arrangement of nano-particle chains or nanofibers that are ductile at room temperature. These microstructures and the corresponding friction data show that the fault slip mechanism is similar to the classical Ashby-Verrall superplasticity, which can produce unstable fault slip. For this mechanism, the diffusion of the diffusion material in the nanocrystalline calcite fault mud is fast enough to control the seismogenic activity in the limestone area. As more and more evidence of the presence of nanoparticle faults is present in the faults within the crust, the proposed mechanism is likely to be universally applicable to seismogenic activity within the crust.