A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilometres long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava tubes. After some time, the eruption tends to become focused at one or more spatter cones. Small fissure vents may not be easily discernible from the air, but the crater rows or the canyons built up by some of them are.
A volcanic fissure and lava channel
Lava channel on Hawaii
Eruption fissure with spatter cones, Holuhraun, Iceland, 2014
Mauna Loa with different lava flows and fissure vent
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from 800 to 1,200 °C. The volcanic rock resulting from subsequent cooling is also often called lava.
Fresh lava from Fagradalsfjall volcano eruption in Iceland, 2023
Toes of a pāhoehoe advance across a road in Kalapana on the east rift zone of Kīlauea Volcano in Hawaii, United States
Columnar jointing in Giant's Causeway in Northern Ireland
Lava enters the Pacific at the Big Island of Hawaii.