Evolution of Elastic and Mechanical Properties During Fault Shear: The Roles of Clay Content, Fabric Development, and Porosity
Evolution of Elastic and Mechanical Properties During Fault Shear: The Roles of Clay Content, Fabric Development, and Porosity
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断层剪切过程中弹性和力学性能的演变：粘土含量、织物发育和孔隙度的作用
DOI：
10.1029/2019jb018612
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Saffer, Demian M.
中科院分区：
文献类型：
--
作者：
Kenigsberg, Abby R.;Rivière, Jacques;Marone, Chris;Saffer, Demian M.
层状硅酸盐由于剪切组构的形成而削弱断层。尽管粘土丰度和组构对断层的摩擦强度、滑动稳定性和孔隙度的影响已得到很好的研究，但它们对弹性性质的影响却鲜为人知，尽管它们是断层刚度的关键因素。我们记录的作用，织物和巩固发挥弹性性能，并表明蒙皂石含量是最重要的因素，确定是否织物或孔隙度控制断层的弹性响应。我们对进入苏门答腊俯冲带的合成蒙皂石-石英断层泥（10-100重量%蒙皂石）和沉积物进行了一系列剪切实验。我们监测Vp，Vs，摩擦，孔隙度，剪切和体积模量。我们发现，具有丰富的蒙皂石的断层泥的机械和弹性性能几乎完全由织物形成（降低剪切的机械和弹性性能）控制。尽管织物控制了蒙脱石贫乏的凿槽在中等剪切应变下的弹性响应，但孔隙率是贯穿大部分剪切的主要控制因素。弹性性质随蒙皂石含量而系统地变化：高蒙皂石泥的值为Vp ~ 1，300 - 1，800 m/s，Vs~ 900- 1，100 m/s，K~ 1-4 GPa，G ~ 1-2 GPa，低蒙皂石泥的值为Vp ~ 2，300 - 2，500 m/s，Vs~ 1，200 - 1，300 m/s，K~ 5-8 GPa，G ~ 2.5-3 GPa。我们发现，即使在蒙脱石贫乏的断层泥中，剪切组构也会影响刚度和弹性模量，这意味着虽然蒙脱石丰度在控制断层泥特性方面发挥了明显的作用，但其他细粒和片状粘土矿物可能会通过控制组构和薄剪切面的发展而产生类似的行为。
Phyllosilicates weaken faults due to the formation of shear fabrics. Although the impacts of clay abundance and fabric on frictional strength, sliding stability, and porosity of faults are well studied, their influence on elastic properties is less known, though they are key factors for fault stiffness. We document the role that fabric and consolidation play in elastic properties and show that smectite content is the most important factor determining whether fabric or porosity controls the elastic response of faults. We conducted a suite of shear experiments on synthetic smectite‐quartz fault gouges (10–100 wt% smectite) and sediment incoming to the Sumatra subduction zone. We monitoredVp,Vs, friction, porosity, shear and bulk moduli. We find that mechanical and elastic properties for gouges with abundant smectite are almost entirely controlled by fabric formation (decreasing mechanical and elastic properties with shear). Though fabrics control the elastic response of smectite‐poor gouges over intermediate shear strains, porosity is the primary control throughout the majority of shearing. Elastic properties vary systematically with smectite content: High smectite gouges have values ofVp~ 1,300–1,800 m/s,Vs~ 900–1,100 m/s,K~ 1–4 GPa, andG~ 1–2 GPa, and low smectite gouges have values ofVp~ 2,300–2,500 m/s,Vs~ 1,200–1,300 m/s,K~ 5–8 GPa, andG~ 2.5–3 GPa. We find that, even in smectite‐poor gouges, shear fabric also affects stiffness and elastic moduli, implying that while smectite abundance plays a clear role in controlling gouge properties, other fine‐grained and platy clay minerals may produce similar behavior through their control on the development of fabrics and thin shear surfaces.
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影响因子：
3.9
作者：
Haines, Samuel H.;van der Pluijm, Ben A.;Marone, Chris
通讯作者：
Marone, Chris
影响因子：
8.6
作者：
Jia, X;Caroli, C;Velicky, B
通讯作者：
Velicky, B
泥岩中的地应力状态和强度
DOI：
10.1002/2016jb012855
发表时间：
2016
期刊：
Journal of Geophysical Research: Solid Earth
影响因子：
--
作者：
B. Casey;J. Germaine;P. Flemings;Brian Fahy
通讯作者：
Brian Fahy
哥斯达黎加俯冲边缘粘土转变与地震之间的联系
影响因子：
5.2
作者：
R. Lauer;D. Saffer;R. Harris
通讯作者：
R. Harris
影响因子：
18.3
作者：
Carpenter, B. M.;Marone, C.;Saffer, D. M.
通讯作者：
Saffer, D. M.