Large ballistically ejected block on Santorini (Greece)
Blocs volcaniques sont des fragments de roche solidifiée plus de 64 mm de diamètre. Blocs communément sont éjectés durant les éruptions explosives et comprennent des pièces plus âgés de l'édifice du volcan, p. ex. les flux de pièces de conduites, de dômes de lave ou de lave âgé.
During violent eruptions, blocks of up to several meter size can be thrown to several km distance. For example, during the Minoan eruption (ca. 1613 BC) of the Santorini volcano in Greece, meter-sized blocks were thrown to up to 7 km horizontal distance and impacted violently into the ground, some of them destroying houses of ancient settlements. The time some of these blocks spent on their trajectories can be easily calculated to be around 30-40 seconds, while they have traveled at speeds of typically 200-300 m/s.
