Velocity-dependent friction measurements, inverse modeling results (aging law) on powdered gouge of ash and scoria samples from Anak Krakatau, Sunda Strait, Indonesia (Table 4)@en

We performed laboratory friction experiments on simulated fault gouges of ash and scoria samples from Anak Krakatau (Sunda Strait, Indonesia), representing the two main lithologies that can be found at Anak Krakatau and measured the velocity-dependence of friction in velocity-step tests. Moreover, we have directly measured cohesion on the samples of powdered gouge of ash and scoria. The experiments were carried out using a single-direct shear device at room temperature. For the shearing tests, all samples were crushed and sieved to a grain size < 125 µm. The ash sample was tested under fluid-saturated conditions (3.5 % NaCl brine) and the scoria sample was tested under fluid-saturated (3.5 % NaCl brine) and room dry conditions. The experiments were carried out at two different effective normal loads, 2.5 and 8 MPa, to simulate different depths of a proto shear plane within the volcanic edifice.我们针对采自印度尼西亚巽他海峡阿纳喀拉喀托火山的火山灰与浮石样品制备的模拟断层泥（fault gouge）开展实验室摩擦实验——这两类岩性是阿纳喀拉喀托火山的主要出露岩性，并通过速度步长实验（velocity-step tests）测定了摩擦的速度依赖性。此外，我们还直接测定了火山灰与浮石粉末断层泥样品的内聚强度。本系列实验均在室温条件下采用单直剪仪（single-direct shear device）完成。剪切实验所用样品均经过粉碎与筛分处理，粒径控制在125 μm以下。其中，火山灰样品仅在流体饱和条件（3.5%氯化钠盐水）下开展测试；浮石样品则分别在流体饱和（3.5%氯化钠盐水）与室温干燥两种条件下进行测试。实验设置了2.5 MPa与8 MPa两种不同的有效法向载荷（effective normal loads），以模拟火山构造内原生剪切面的不同埋藏深度。