High-speed imaging of Strombolian explosions: The ejection velocity of pyroclasts

摘要: Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in Earth's crust. Knowledge velocity is crucial for understanding modeling relevant physical processes an eruption, yet direct measurements still difficult task with largely variable results. Here we apply pioneering high-speed imaging to measure pyroclasts Strombolian explosive unparalleled temporal resolution. Measured supersonic velocities, up 405 m/s, twice higher than previously reported such eruptions. Individual explosions include multiple, sub-second-lasting pulses characterized by exponential decay velocity. When fitted empirical model shock-tube experiments literature, this allows constraining length pressurized pockets responsible pulses. These results directly impact eruption related hazard assessment, well interpretation geophysical signals monitoring networks.