Surface rupture in stochastic slip models
Surface rupture in stochastic slip models
复制标题
随机滑移模型中的表面破裂
DOI：
10.1093/gji/ggaa055
复制
发表时间：
2020
影响因子：
2.8
通讯作者：
A. Herrero
中科院分区：
文献类型：
--
作者：
S. Murphy;A. Herrero
作为谱方法的替代方法，通过将圆形滑移位错的幂律缩放尺寸频率分布放置在断层表面上，可以通过复合源模型产生随机自相似滑移。然而，这些模型并不能准确地解释观察到的表面破裂行为。我们建议对复合源模型进行修改以纠正此问题。该技术的优点是它适应于非平面断层表面上分形滑移分布的使用。然而，为了使用这种技术模拟地表破裂，释放断层顶部的边界条件，我们观察到浅层滑移的系统性减少。我们提出了一种新策略，将表面视为反射器，并将滑移折回到断层上。基于此原理提出了两种不同的技术：第一种是图像方法。它需要对预先存在的代码进行少量更改，并且适用于平面故障。第二个涉及多级三边测量技术的使用。它适用于由非结构化网格描述的非平面故障。使用这两种技术计算出的反射滑移在平面断层上几乎相同，表明它们是等效的。应用这种校正，在复合源模型中考虑反射滑移，不再观察到浅深度处滑移的缺乏，并且不存在随深度的系统趋势。然而，还有其他参数可能会影响断层面上滑移的空间分布。例如，用于放置子事件的概率密度函数的类型也很重要。在最大滑移位置已知为一阶的情况下，高斯可能适合描述概率函数。对于危害评估研究，统一的概率密度函数更合适，因为它不提供潜在的系统空间趋势。
As an alternative to spectral methods, stochastic self-similar slip can be produced through a composite source model by placing a power-law scaling size-frequency distribution of circular slip dislocations on a fault surface. However these models do not accurately account for observed surface rupture behaviour. We propose a modification to the composite source model that corrects this issue. The advantage of this technique is that it accommodates the use of fractal slip distributions on non-planar fault surfaces. However to mimic a surface rupture using this technique, releasing the boundary condition at the top of the fault, we observed a systematic decrease in slip at shallow depths. We propose a new strategy whereby the surface is treated like a reflector with the slip being folded back onto the fault. Two different techniques based on this principal are presented: the first is the method of images. It requires a small change to pre-existing codes and works for planar faults. The second involves the use of a multistage trilateration technique. It is applied to non-planar faults described by an unstructured mesh. The reflected slip calculated using the two techniques is near identical on a planar fault, suggesting they are equivalent. Applying this correction, where reflected slip is accounted for in the composite source model, the lack of slip at shallow depths is not observed any more and there is no systematic trend with depth. However, there are other parameters which may affect the spatial distribution of slip across the fault plane. For example, the type of probability density function used in the placement of the subevent is also important. In the case where the location of maximum slip is known to a first order, a Gaussian may be appropriate to describe the probability function. For hazard assessment studies a uniform probability density function is more suitable as it provides no underlying systematic spatial trend.
影响因子：
3
作者：
Y. Okada
通讯作者：
Y. Okada