An experimental investigation of the dynamics and morphology of granular eruptions induced by high-pressure gas

This study investigates the dynamics and morphological evolution of granular media eruptions driven by high-pressure gas release. Experiments are conducted using a custom-built gas–solid eruption apparatus integrated with high-speed imaging and synchronous measurement techniques. Four distinct eruption regimes are identified: the rising, bubbling, transitional, and eruptive regimes, governed by the dimensionless overpressure ΠP = P/(ρsgH) and the dimensionless volume ΠV = V/H3. Quantitative analysis reveals that the normalized crater depth d/H increases approximately linearly with ΠP at lower pressures but saturates in the high-pressure regime, while the crater diameter D/H exhibits a linear correlation with ΠP. In contrast, ΠV has a negligible influence on the crater morphology. The bubble evolution exhibits characteristic spatiotemporal patterns: height development is regulated by ΠV, width expansion follows a universal linear scaling law, and the aspect ratio evolves through three distinct stages. Based on experimental data, we establish a phase diagram for regime transitions in the ΠP–ΠV parameter space and derive critical criterion functions for the eruption-to-transition and transition-to-bubble boundaries. This work elucidates the multi-scale dynamics of gas–solid eruptions, providing experimental evidence and a theoretical framework for predicting geological hazards associated with natural gas hydrate dissociation and shallow gas seepage.