Fig. 7
From: Physical characteristics of scoriae and ash from 2014–2015 eruption of Aso Volcano, Japan
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