{"title":"Effects of fault roughness on estimating critical slip-weakening distance from fault slip history: A laboratory study","authors":"Peng Dong , Zhengyan Wang , Ying Xu , Kaiwen Xia","doi":"10.1016/j.tecto.2024.230419","DOIUrl":null,"url":null,"abstract":"<div><p>Earthquakes are the dynamic rupture of faults governed by fault weakening processes. Critical slip-weakening distance (<em>D</em><sub>c</sub>) is a crucial source parameter of earthquakes, and the determination of <em>D</em><sub>c</sub> is of great concern to semiologists. However, determining <em>D</em><sub>c</sub> for natural earthquakes is challenging due to the trade-off in inversed source models. To solve this problem, Fukuyama and his coworkers proposed a simple method (denoted as the F&M method) to estimate <em>D</em><sub>c</sub> directly from slip-velocity functions. According to the F&M method, the fault slip at the peak slip velocity (<em>D</em><sub>c</sub>') can be used as an approximation of <em>D</em><sub>c</sub>. However, the feasibility of this method has not been completely resolved. Here, we performed laboratory earthquake rupture experiments to examine the validity of the F&M method. Experiments were conducted on faults with different roughness and stress level. We studied the effect of fault roughness on the validity of the F&M method. Our results show that the increase in fault roughness could complicate the fault weakening process, producing repeated weakening and strengthening phase, which leads to a prominent deviation between <em>D</em><sub>c</sub>' and <em>D</em><sub>c</sub>. Furthermore, we also observed a correlation between the critical slip-weakening distance <em>D</em><sub>c</sub> and the final fault slip <em>D</em>. Such correlation implies the scale-dependent nature of <em>D</em><sub>c</sub>, which is consistent with seismic observations in the field.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"885 ","pages":"Article 230419"},"PeriodicalIF":2.7000,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Tectonophysics","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S004019512400221X","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Earthquakes are the dynamic rupture of faults governed by fault weakening processes. Critical slip-weakening distance (Dc) is a crucial source parameter of earthquakes, and the determination of Dc is of great concern to semiologists. However, determining Dc for natural earthquakes is challenging due to the trade-off in inversed source models. To solve this problem, Fukuyama and his coworkers proposed a simple method (denoted as the F&M method) to estimate Dc directly from slip-velocity functions. According to the F&M method, the fault slip at the peak slip velocity (Dc') can be used as an approximation of Dc. However, the feasibility of this method has not been completely resolved. Here, we performed laboratory earthquake rupture experiments to examine the validity of the F&M method. Experiments were conducted on faults with different roughness and stress level. We studied the effect of fault roughness on the validity of the F&M method. Our results show that the increase in fault roughness could complicate the fault weakening process, producing repeated weakening and strengthening phase, which leads to a prominent deviation between Dc' and Dc. Furthermore, we also observed a correlation between the critical slip-weakening distance Dc and the final fault slip D. Such correlation implies the scale-dependent nature of Dc, which is consistent with seismic observations in the field.
地震是受断层削弱过程支配的断层动态破裂。临界滑动削弱距离(Dc)是地震的一个重要震源参数,如何确定 Dc 是震源学家们非常关心的问题。然而,由于反演震源模型中的权衡问题,确定天然地震的 Dc 具有挑战性。为了解决这个问题,福山和他的同事提出了一种简单的方法(称为 F&M 方法),直接从滑动速度函数估算 Dc。根据 F&M 方法,可以用峰值滑移速度下的断层滑移(Dc')作为 Dc 的近似值。然而,这种方法的可行性尚未完全解决。在此,我们进行了实验室地震破裂实验,以检验 F&M 方法的有效性。实验在不同粗糙度和应力水平的断层上进行。我们研究了断层粗糙度对 F&M 方法有效性的影响。结果表明,故障粗糙度的增加会使故障削弱过程复杂化,产生反复的削弱和强化阶段,从而导致 Dc' 和 Dc 之间的显著偏差。此外,我们还观察到临界滑动削弱距离 Dc 与最终断层滑动 D 之间存在相关性。这种相关性意味着 Dc 具有规模依赖性,这与实地地震观测结果一致。
期刊介绍:
The prime focus of Tectonophysics will be high-impact original research and reviews in the fields of kinematics, structure, composition, and dynamics of the solid arth at all scales. Tectonophysics particularly encourages submission of papers based on the integration of a multitude of geophysical, geological, geochemical, geodynamic, and geotectonic methods