noun
fissure eruption
A volcanic eruption occurring along a linear fracture or crack in the earth's surface, rather than from a central vent. Technical term used in geology and volcanology.
アイスランドでは割れ目噴火がよく見られる。
Fissure eruptions are often observed in Iceland.
噴火 is the general term for 'eruption'. 割れ目噴火 specifies the type of eruption occurring from a fissure.
Compound of 割れ目 (crack, fissure) and 噴火 (eruption). The derivation is transparent from its components.