Fissure vent

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.^[1] 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.

A volcanic fissure and lava channel with lava fountain

Channel of lava erupted during a fissure eruption of Kīlauea volcano, Hawaii, 2007

Eruption fissure with spatter cones, Holuhraun, Iceland, 2014

Mauna Loa with different lava flows and fissure vent

A volcanic fissure eruption on Fagradalsfjall, Iceland, 2021

Crater row of Laki

Eldhraun, a lava field produced by the Laki craters

Cinder cones on Etna

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.^[2][3]

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.^[4] 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.^[5]

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.^[6] During the Eldgjá eruption A.D. 934–40, another very big effusive fissure eruption in the volcanic system of Katla in South Iceland, ~18 km³ (4.3 cu mi) of lava were released.^[7] 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.^[8]

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.^[9] 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

Name	Elevation		Location	Last eruption
	metres	feet	Coordinates
Quetena	5730	18799	22.25°S 67.42°W / -22.25; -67.42 (Quetena)	Unknown
Ray Mountain	2050	6730	52.23°N 120.12°W / 52.23; -120.12 (Ray Mountain)	Pleistocene
Cordón Caulle	1798	5899	40.46°S 72.25°W / -40.46; -72.25 (Cordón Caulle)	2011
Manda-Inakir	600+	1968	12.38°N 42.20°E / 12.38; 42.20 (Manda-Inakir)	1928
Alu	429	1407	13.82°N 40.55°E / 13.82; 40.55 (Alu)	Unknown
Hertali	900	2953	9.78°N 40.33°E / 9.78; 40.33 (Hertali)	Unknown
Eldgjá	800	2625	63.88°N 18.77°W / 63.88; -18.77 (Eldgjá)	934
Fagradalsfjall	385	1263	63.88°N 22.27°W / 63.88; -22.27 (Fagradalsfjall)	2023
Holuhraun	730	2395	64.87°N 16.83°W / 64.87; -16.83 (Nornahraun)	2014
Krafla	650	2130	65.73°N 16.78°W / 65.73; -16.78 (Krafla)	1984
Laki	620	2034	64.07°N 18.23°W / 64.07; -18.23 (Laki)	1784
Litli-Hrútur	312	1024	63.92°N 22.21°W / 63.92; -22.21 (Litli-Hrútur)	2023
Sundhnúkur	98	322	63.88°N 22.39°W / 63.88; -22.39 (Sundhnúkur)	2024 (ongoing)
Banda Api	640	2100	4.525°S 129.871°E / -4.525; 129.871 (Banda Api)	1988
Koma-ga-take				1996
Kuchinoerabu				1980
Singu Plateau	507	1663	22.70°N 95.98°E / 22.70; 95.98 (Singu Plateau)	Unknown
Estelí	899	2949	13.17°N 86.40°W / 13.17; -86.40 (Estelí)	Unknown
Pagan				1981
Nejapa Miraflores	360	1181	12.12°N 86.32°W / 12.12; -86.32 (Nejapa Miraflores)	Unknown
Tor Zawar[10]	2237	7339	30°28′45″N 67°28′30″E	2010
São Jorge Island	1053	3455	38.65°N 28.08°W / 38.65; -28.08 (São Jorge Island)	1907
Tolbachik				1975
Cumbre Vieja	1949	6394	28°34′N 17°50′W	2021
Lanzarote	670	2198	29.03°N 13.63°W / 29.03; -13.63 (Lanzarote)	1824
Butajiri Silti Field	2281	7484	8.05°N 83.85°E / 8.05; 83.85 (Butajiri Silti Field)	Unknown

References

1. Gudmundsson, A.; Brenner, S.L. (2004). "Local stresses, dyke arrest and surface deformation in volcanic edifices and rift zones". Annals of Geophysics. 47 (4): 1433–1454. doi:10.4401/ag-3352.
2. "V. Camp, Dept. of Geologic Sciences, Univ. of San Diego: How volcanoes work. Eruption types. Fissure eruptions". Archived from the original on 2018-02-28. Retrieved 2014-09-24.
3. "Geology glossary". www.volcanodiscovery.com. Retrieved September 25, 2001.
4. Einarsson, Páll (2008). "Plate boundaries, rifts and transforms in Iceland" (PDF). Jökull. 58 (12): 35–58. doi:10.33799/jokull2008.58.035. S2CID 55021384. Archived from the original (PDF) on 2017-11-18. Retrieved 2014-09-24.
5. Thordarson, Thorvaldur; Höskuldsson, Ármann (2008). "Postglacial volcanism in Iceland" (PDF). Jökull. 58 (198): e228. doi:10.33799/jokull2008.58.197. S2CID 53446884.
6. "Institute of Earth Sciences, University of Iceland: Grímsvötn. Received 9/24, 2014". Archived from the original on 2018-05-14. Retrieved 2014-09-24.
7. Institute of Earth Sciences, University of Iceland: Katla. Received 9/24, 2014.
8. "Institute of Earth Sciences, University of Iceland: Bardarbunga 2014". Archived from the original on 2021-04-15. Retrieved 2014-09-24.
9. Rader, Erika; Geist, Dennis (2015-10-01). "Eruption conditions of spatter deposits". Journal of Volcanology and Geothermal Research. 304: 287–293. doi:10.1016/j.jvolgeores.2015.09.011. ISSN 0377-0273.
10. Kerr, A. C; Khan, M; McDonald, I (2010). "Eruption of basaltic magma at Tor Zawar, Balochistan, Pakistan on 27 January 2010: Geochemical and petrological constraints on petrogenesis". Mineralogical Magazine. 74 (6): 1027–36. Bibcode:2010MinM...74.1027K. doi:10.1180/minmag.2010.074.6.1027. S2CID 129864863.

External links

• Media related to Fissure vents at Wikimedia Commons
• Detailed list and KML files for Fissure Vents
• Volcanolive.com Page on Fissure Vents