Fig. 7
From: Physical characteristics of scoriae and ash from 2014–2015 eruption of Aso Volcano, Japan
![Fig. 7](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40623-018-0914-5/MediaObjects/40623_2018_914_Fig7_HTML.png)
Friction coefficient and fracturing of a scoria. a Shear (solid curve) and normal (dotted curve) stresses to deform Sample 3 measured under one-directional rotation with two shear rates (red curve) at \(T=500\,^{\circ } \hbox {C}\). b Friction coefficient \(\mu =\sigma _{{\tau }}/\sigma _{\mathrm{N}}\) and the thickness of the sample