Blloqe vullkanike janë solidified fragmente guri më i madh se 64 mm në diametër. Blocks zakonisht janë të hidhet gjatë shpërthimeve eksplozive dhe përbëhet nga pjesë të vjetër të ngrehinës e vullkanit, p.sh. pjesë e kanalit, pro apo rrjedhave lavë të vjetër lavë.

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.