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. Volcanic cones and their craters that are aligned along a fissure form a crater row. Small fissure vents may not be easily discernible from the air, but the crater rows (see Laki) or the canyons (see Eldgjá) built up by some of them are.

The dikes that feed fissures reach the surface from depths of a few kilometers and connect them to deeper magma reservoirs, often under volcanic centers. Fissures are usually found in or along rifts and rift zones, such as Iceland and the East African Rift. Fissure vents are often part of the structure of shield volcanoes.

Iceland

In Iceland, volcanic vents, which can be long fissures, often open parallel to the rift zones where the Eurasian and the North American lithospheric plates are diverging, a system which is part of the Mid-Atlantic Ridge. Renewed eruptions generally occur from new parallel fractures offset by a few hundred to thousands of metres from the earlier fissures. This distribution of vents and sometimes voluminous eruptions of fluid basaltic lava usually builds up a thick lava plateau, rather than a single volcanic edifice. But there are also the central volcanoes, composite volcanoes, often with calderas, which have been formed during thousands of years, and eruptions with one or more magma reservoirs underneath controlling their respective fissure system.

The Laki fissures, part of the Grímsvötn volcanic system, produced one of the biggest effusive eruptions on earth in historical times, in the form of a flood basalt of 12–14 km3 of lava in 1783. During the Eldgjá eruption A.D. 934–40, another very big effusive fissure eruption in the volcanic system of Katla in South Iceland, ~ of lava were released. In September 2014, a fissure eruption was ongoing on the site of the 18th century lava field Holuhraun. The eruption is part of an eruption series in the Bárðarbunga volcanic system.

Hawaii

The radial fissure vents of Hawaiian volcanoes also produce "curtains of fire" as lava fountains erupting along a portion of a fissure. These vents build up low ramparts of basaltic spatter on both sides of the fissure. More isolated lava fountains along the fissure produce crater rows of small spatter and cinder cones. The fragments that form a spatter cone are hot and plastic enough to weld together, while the fragments that form a cinder cone remain separate because of their lower temperature.

List of fissure vents Sourced from the Global Volcanism Program's Volcanoes of the World database (v. 5.3.6), filtered to entries whose Primary Volcano Type is "Fissure vent" or "Fissure vent(s)".

NameElevationLocationLast known eruption metresfeetCoordinates Quetena 5730 18799 Pleistocene Gran Canaria 1950 6398 40 CE Dzau 1904 6247 Pleistocene East Ziway 1889 6198 Unknown Hofsjökull 1765 5791 Unknown Eagle Lake Field 1652 5420 Pleistocene Katla 1490 4888 1918 Prestahnúkur 1385 4544 3350 BCE Bolaven Plateau 1350 4429 Pleistocene Oddnýjarhnjúkur–Langjökull 1100 3609 950 São Jorge Island 1053 3455 1902 Fjallgarðar Ridge 1035 3396 Pleistocene Tungnaárfjöll 983 3225 Pleistocene Hertali 900 2953 Unknown Estelí 899 2949 Pleistocene Lambafjöll 840 2756 Pleistocene Manda Gargori 700 2297 Unknown Lanzarote 670 2198 1824 Manda-Inakir 600 1969 1928 Dalaffilla 578 1896 2008 Fuerteventura 529 1736 Unknown Namyong 508 1667 Pleistocene Singu Plateau 507 1663 Pleistocene Heiðarsporðar 490 1608 300 BCE Nejapa-Miraflores 360 1181 1060 Picos Volcanic Fissural System 350 1148 1652 Sukadana Basalts 300 984 Pleistocene Ardoukoba 298 978 1978 Vestmannaeyjar 283 928 1973 Granada 250 820 Unknown Fagradalsfjall 250 820 2023 Lucareț Basalts 190 623 Pleistocene Medaw Island 115 377 Pleistocene Poros 80 262 Pleistocene Eldey 70 230 1926 Thaton 30 98 Pleistocene Kolbeinsey Ridge 5 16 1755 Tjörnes Fracture Zone −75 −246 1868 Monaco Bank −197 −646 1911 Hollister Ridge −1000 −3281 Unknown West Mata −1174 −3852 2009 Titan Ridge Volcano −1300 −4265 1972 Tafu-Maka −1400 −4593 2008 Axial Seamount −1410 −4626 2015 Romanche Fracture Zone −1528 −5013 Unknown Escanaba Segment −1700 −5577 2260 BCE Vance Segment −1985 −6512 Pleistocene Endeavour Segment −2050 −6726 3490 BCE Cobb Segment −2100 −6890 1180 BCE Cleft Segment −2140 −7021 1986 Northern EPR at 16°N −2300 −7546 50 BCE CoAxial Segment −2400 −7874 1993 Galapagos Rift at 86°W −2430 −7972 1996 Northern EPR at 9.8°N −2500 −8202 2025 West Valley Segment −2550 −8366 Unknown Southern EPR at 17.5°S (Segment K) −2566 −8419 1990 Southern EPR at 18.5°S (Segment I) −2600 −8530 1915 Southern EPR at 18.2°S (Segment J) −2650 −8694 1890 Northern EPR at 17°N −2700 −8858 50 BCE Southern EPR at 8°S −2800 −9186 1969 Northern EPR at 10.7°N −2900 −9514 2003 North Gorda Ridge Segment −3000 −9843 1996 East Blanco Depression −3000 −9843 Unknown Phoenix Segment −3000 −9843 Pleistocene Jackson Segment −3100 −10171 Unknown Central Segment −3300 −10827 Pleistocene East Gakkel Ridge at 85°E −3800 −12467 1999 Mariana Back-Arc Segment at 15.5°N −4100 −13451 2015 Pico Fracture Zone −4200 −13780 1865 Udintsev Transform −5700 −18701 Unknown Olim Pleistocene Geureugoh Pleistocene Mostyn Pleistocene Cerro Grande Pleistocene Hreppar Pleistocene

References

External links

Detailed list and KML files for Fissure Vents Volcanolive.com Page on Fissure Vents