Pyroclastic flows from Unzen were generated by gravitational collapse of the growing lava dome, near the city of Shimabara, Nagasaki (1991). Most of the flows traveled from 1 to 3 km, but some flows reached more than 4 km, burning houses and killing people in the evacuated zone of Kita-kamikoba on the eastern foot of the volcano.The velocities of the flows ranged from 15 to 25 m/s on the gentle middle flank. Scientific paper: http://link.springer.com/article/10.1007/BF00301514#page-1 Other detai

When a volcano erupts, pyroclastic flows are often the biggest danger to anyone nearby. These fast-flowing currents of rock, ash and hot gas are extremely difficult to study, so researchers created their own. Read the related Nature Geoscience paper here: https://go.nature.com/2Im1bYs | Nature Portfolio