Rheological study of lava flow analog mixtures

Abstract

Laboratory and numerical modeling have been used to study and describe volcanic systems and magmatic processes for more than 100 years. The laboratory experiments, where the eruption parameters and material properties are firmly controlled, lead to finding lava flow behavior and the influence of various factors on flow evolution. Another advantage of our understanding of lava parameters and processes leads to the development of more sophisticated physical models improving the understanding of this phenomenon. In laboratory experiments, since the testing of silicate melt is difficult and dangerous, flow emplacement can be simulated by using analogous material. In this paper, we examined several materials to find a better analog that can be used as lava. We used PEG and wax as a substrate and added six additional materials in different proportions. To find out the behavior of the mixtures cone-and-plate type rheometer was used. Adding Si-acid to the mixture caused non-Newtonian behavior in both PEG and wax. In all mixtures the shear rate increases during decreasing viscosity which expresses shear thinning behavior. So, this new mixture can be used as an analog material to model the behavior of lavas during magma rise in conduits and when lava flows on Earth's surface.