Lava fountain 450 m (1,475 ft) high from Kīlauea Pu‘u ‘Ō‘ō eruption...

Lava fragments ejected by lava fountains are called tephra, a general term for all fragments, regardless of size, that are blasted into the air by explosive activity. A variety of terms are also used to describe specific types of fragments, including Pele's hair, Pele's tears, scoria, spatter, bombs, and reticulite. Other terms are used to describe the size of fragments, including blocks (>64 mm in diameter), lapilli (2 to 64 mm in diameter), and ash. Volcanic ash, jagged pieces of rock and glass less than 2 mm (0.08 in) in diameter, affect more people, infrastructure, and daily activities worldwide than any other eruptive phenomena. Pu‘u ‘Ō‘ō vent is on Kīlauea's East Rift Zone.