Abstract
The volcanic eruption is categorized into non-explosive eruption with static magma flow and explosive eruption with shock wave. Volcanic eruption is a phenomenon of sudden eruption of high-pressure magma by the sudden decompression after pressure release. In the present study, it is experimentally investigated by using the simulant material what is the dominant mechanism which divides the explosive eruption and non-explosive eruption. The effects of volatile substance and viscosity of the material on the phase change behavior under the sudden decompression are investigated with transparent visible shock tube apparatus which simulate the volcanic sudden decompression with two-fluids component system of silicone oil as high viscosity fluid and acetone as volatile substance. In the experiment, it is observed that simulant material suddenly erupts upward after sudden decompression. It is experimentally confirmed from the experimental results that the flow pattern is changed when eruption speed changes. It is suggested that the nonlinear change of the eruption behavior is caused by the interaction between volatile substance vaporization and viscosity resistance.
