{{Short description|Roughly circular protrusion from slowly extruded viscous volcanic lava}} [[File:Volcán Chaitén-Sam Beebe-Ecotrust.jpg|thumb|right|Rhyolitic lava dome of Chaitén Volcano during its 2008–2010 eruption]] [[File:Mono Crater closeup-1000px.jpeg|thumb|right|One of the Inyo Craters, an example of a rhyolite dome]] [[File:Nea Kameni.jpg|thumb|right|Nea Kameni seen from Thera, Santorini]] In volcanology, a '''lava dome''' is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings.<ref name=":0">{{Cite book|title=The Encyclopedia of Volcanoes|last1=Calder|first1=Eliza S.|last2=Lavallée|first2=Yan|last3=Kendrick|first3=Jackie E.|last4=Bernstein|first4=Marc|date=2015|publisher=Elsevier|isbn=9780123859389|pages=343–362|doi=10.1016/b978-0-12-385938-9.00018-3}}</ref> Around 6% of eruptions on Earth form lava domes.<ref name=":0" /> The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day).<ref name=eov>{{Cite encyclopedia |last1=Fink |first1=Jonathan H. |last2=Anderson |first2=Steven W. |editor-last=Sigursson |editor-first=Haraldur |title=Lava Domes and Coulees |encyclopedia=Encyclopedia of Volcanoes |pages=307–19 |publisher=Academic Press |date=2001 }}</ref> The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite.

Existence of lava domes has been suggested for some domed structures on the Moon, Venus, and Mars,<ref name=":0" /> e.g. the Martian surface in the western part of Arcadia Planitia and within Terra Sirenum.<ref>{{cite journal|last1=Rampey|first1=Michael L.|last2=Milam|first2=Keith A.|last3=McSween|first3=Harry Y.|last4=Moersch|first4=Jeffrey E.|last5=Christensen|first5=Philip R.|title=Identity and emplacement of domical structures in the western Arcadia Planitia, Mars|journal=Journal of Geophysical Research|date=28 June 2007|volume=112|issue=E6|pages=E06011|doi=10.1029/2006JE002750|bibcode=2007JGRE..112.6011R|doi-access=free}}</ref><ref>{{cite journal|last1=Brož|first1=Petr|last2=Hauber|first2=Ernst|last3=Platz|first3=Thomas|last4=Balme|first4=Matt|title=Evidence for Amazonian highly viscous lavas in the southern highlands on Mars|journal=Earth and Planetary Science Letters|date=April 2015|volume=415|pages=200–212|doi=10.1016/j.epsl.2015.01.033|url=https://zenodo.org/record/889322|bibcode=2015E&PSL.415..200B|hdl=11104/0244774|hdl-access=free}}</ref>

==Dome dynamics== [[File:MSH06 aerial crater from north high angle 09-12-06.jpg|right|thumb|Lava domes in the crater of Mount St. Helens]] Lava domes evolve unpredictably, due to non-linear dynamics caused by crystallization and outgassing of the highly viscous lava in the dome's conduit.<ref>{{Citation|title=Nonlinear dynamics of lava dome extrusion|journal=Nature|volume=402|pages=37–41 |date=4 November 1999 |url=https://www.geo.mtu.edu/EHaz/VolcanoInstability_class/melnik/melnik%20sparks%20nature.pdf|first1=O|last1=Melnik|first2=R. S. J. |last2=Sparks|doi=10.1038/46950|issue=6757|bibcode = 1999Natur.402...37M |s2cid=4426887}}</ref> Domes undergo various processes such as growth, collapse, solidification and erosion.<ref>{{Cite journal|last1=Darmawan|first1=Herlan|last2=Walter|first2=Thomas R.|last3=Troll|first3=Valentin R.|last4=Budi-Santoso|first4=Agus|date=2018-12-12|title=Structural weakening of the Merapi dome identified by drone photogrammetry after the 2010 eruption|url=https://nhess.copernicus.org/articles/18/3267/2018/|journal=Natural Hazards and Earth System Sciences|language=en|volume=18|issue=12|pages=3267–3281|doi=10.5194/nhess-18-3267-2018|bibcode=2018NHESS..18.3267D |issn=1561-8633|doi-access=free}}</ref>

Lava domes grow by endogenic dome growth or exogenic dome growth. The former implies the enlargement of a lava dome due to the influx of magma into the dome interior, and the latter refers to discrete lobes of lava emplaced upon the surface of the dome.<ref name=eov /> It is the high viscosity of the lava that prevents it from flowing far from the vent from which it extrudes, creating a dome-like shape of sticky lava that then cools slowly in-situ.<ref>{{Cite journal |last1=Darmawan |first1=Herlan |last2=Troll |first2=Valentin R. |last3=Walter |first3=Thomas R. |last4=Deegan |first4=Frances M. |last5=Geiger |first5=Harri |last6=Heap |first6=Michael J. |last7=Seraphine |first7=Nadhirah |last8=Harris |first8=Chris |last9=Humaida |first9=Hanik |last10=Müller |first10=Daniel |date=2022-02-25 |title=Hidden mechanical weaknesses within lava domes provided by buried high-porosity hydrothermal alteration zones |journal=Scientific Reports |language=en |volume=12 |issue=1 |pages=3202 |doi=10.1038/s41598-022-06765-9 |pmid=35217684 |pmc=8881499 |bibcode=2022NatSR..12.3202D |issn=2045-2322}}</ref> Spines and lava flows are common extrusive products of lava domes.<ref name=":0" /> Domes may reach heights of several hundred meters, and can grow slowly and steadily for months (e.g. Unzen volcano), years (e.g. Soufrière Hills volcano), or even centuries (e.g. Mount Merapi volcano). The sides of these structures are composed of unstable rock debris. Due to the intermittent buildup of gas pressure, erupting domes can often experience episodes of explosive eruption over time.<ref>{{Cite journal|last1=Heap|first1=Michael J.|last2=Troll|first2=Valentin R.|last3=Kushnir|first3=Alexandra R. L.|last4=Gilg|first4=H. Albert|last5=Collinson|first5=Amy S. D.|last6=Deegan|first6=Frances M.|last7=Darmawan|first7=Herlan|last8=Seraphine|first8=Nadhirah|last9=Neuberg|first9=Juergen|last10=Walter|first10=Thomas R.|date=2019-11-07|title=Hydrothermal alteration of andesitic lava domes can lead to explosive volcanic behaviour|journal=Nature Communications|language=en|volume=10|issue=1|pages=5063|doi=10.1038/s41467-019-13102-8|pmid=31700076 |pmc=6838104 |bibcode=2019NatCo..10.5063H |issn=2041-1723|doi-access=free}}</ref> If part of a lava dome collapses and exposes pressurized magma, pyroclastic flows can be produced.<ref>{{Citation|last1=Parfitt|first1=E.A.|last2=Wilson|first2=L|date=2008|title=Fundamentals of Physical Volcanology|location=Massachusetts|publisher=Blackwell Publishing|page=256}}</ref> Other hazards associated with lava domes are the destruction of property from lava flows, forest fires, and lahars triggered from re-mobilization of loose ash and debris. Lava domes are one of the principal structural features of many stratovolcanoes worldwide. Lava domes are prone to unusually dangerous explosions since they can contain rhyolitic silica-rich lava.

Characteristics of lava dome eruptions include shallow, long-period and hybrid seismicity, which is attributed to excess fluid pressures in the contributing vent chamber. Other characteristics of lava domes include their hemispherical dome shape, cycles of dome growth over long periods, and sudden onsets of violent explosive activity.<ref>{{Citation | last = Sparks | first = R.S.J. | title = Causes and consequences of pressurisation in lava dome eruptions | journal = Earth and Planetary Science Letters | volume = 150 | issue = 3–4 | pages = 177–189 | date = August 1997 | doi = 10.1016/S0012-821X(97)00109-X | bibcode=1997E&PSL.150..177S}}</ref> The average rate of dome growth may be used as a rough indicator of magma supply, but it shows no systematic relationship to the timing or characteristics of lava dome explosions.<ref>{{Citation | last1 = Newhall | first1 = C.G. | last2 = Melson. | first2 = W.G. | title = Explosive activity associated with the growth of volcanic domes | journal = Journal of Volcanology and Geothermal Research | volume = 17 | issue = 1–4 | pages = 111–131 | date = September 1983 | doi = 10.1016/0377-0273(83)90064-1 |bibcode = 1983JVGR...17..111N }}</ref>

Gravitational collapse of a lava dome can produce a block and ash flow.<ref name=encyclovolc2015>{{Cite book|title =Encyclopedia of Volcanoes |chapter= Chapter 54 – Hazards from Pyroclastic Density Currents|doi=10.1016/B978-0-12-385938-9.00037-7|publisher = Academic Press|date = 2015|edition=2nd|location = Amsterdam|isbn = 978-0-12-385938-9|pages = 943–956|first1 = Paul D.|last1 = Cole|first2 =Augusto |last2 =Neri |first3 =Peter J.|last3 = Baxter|editor-first = Haraldur|editor-last = Sigurdsson|editor-link=Haraldur Sigurdsson}}</ref>

==Related landforms== ===Cryptodomes=== thumb|right|The bulging cryptodome of Mt. St. Helens on April 27, 1980

A '''cryptodome''' (from the Greek {{lang|grc|κρυπτός}}, {{Transliteration|grc|kryptos}}, "hidden, secret") is a dome-shaped structure created by accumulation of viscous magma at a shallow depth.<ref>{{Cite web |url=https://volcanoes.usgs.gov/vsc/glossary/cryptodome.html |title=USGS: Volcano Hazards Program Glossary - Cryptodome |website=volcanoes.usgs.gov |access-date=2018-06-23}}</ref> Two examples of cryptodomes were the ones leading to the 1956 eruption of Bezymianny and the 1980 eruption of Mount St. Helens. In each case, the explosive eruption began after the cryptodome caused the side of the volcano to bulge outward and led to a sector collapse, in turn leading to explosive decompression of the subterranean cryptodome.<ref name="CVOMountStHelens">{{Cite web |url=https://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_geo_hist_99.html |title=USGS: Volcano Hazards Program CVO Mount St. Helens |website=volcanoes.usgs.gov |access-date=2018-06-23 |archive-date=2018-05-28 |archive-url=https://web.archive.org/web/20180528180417/https://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_geo_hist_99.html |url-status=dead }}</ref><ref name="Donnadieu_etal_2001">{{cite journal | title=Volcanic edifice stability during cryptodome intrusion | first1=F. | last1=Donnadieu | first2=O. | last2=Merle | first3=J-C. | last3=Besson | journal=Bulletin of Volcanology | year=2001 | volume=63 | issue=1 | pages=61–72 | doi=10.1007/s004450000122| bibcode=2001BVol...63...61D }}</ref>

===Lava spine/Lava spire=== {{Main|Lava spine}} thumb|Soufrière Hills lava spine before the 1997 eruption thumb|right | Lava dome growth during the 2004–2008 eruptive phase of Mount St Helens A lava spine or lava spire is a growth that can form on the top of a lava dome. A lava spine can increase the instability of the underlying lava dome. A recent example of a lava spine is the spine formed in 1997 at the Soufrière Hills Volcano on Montserrat.

===Lava coulées=== [[File:Chao dacite domes.jpg|thumb|left|Chao dacite coulée flow-domes (left center), northern Chile, viewed from Landsat 8]] Coulées (or coulees) are lava domes that have experienced some flow away from their original position, thus resembling both lava domes and lava flows.<ref name="eov" />

The world's largest known dacite flow is the Chao dacite dome complex, a huge coulée flow-dome between two volcanoes in northern Chile. This flow is over {{convert|14|km}} long, has obvious flow features like pressure ridges, and a flow front {{convert|400|m}} tall (the dark scalloped line at lower left).<ref>[http://earthobservatory.nasa.gov/IOTD/view.php?id=82424 Chao dacite dome complex] at NASA Earth Observatory</ref> There is another prominent coulée flow on the flank of Llullaillaco volcano, in Argentina,<ref>[https://www.wired.com/wiredscience/2010/03/coulees/ Coulées!] by Erik Klemetti, an assistant professor of Geosciences at Denison University.</ref> and other examples in the Andes. {{clear}}

==Examples of lava domes== {{Main|List of lava domes}} {| class="wikitable sortable" |+ Lava domes ! Name of lava dome !! Country !! Volcanic area !! Composition !! Last eruption<br />or growth episode |- | Chaitén lava dome || Chile || Southern Volcanic Zone || Rhyolite || 2009 |- | Ciomadul lava domes || Romania || Carpathians || Dacite || Pleistocene |- | Cordón Caulle lava domes || Chile || Southern Volcanic Zone || Rhyodacite to Rhyolite || Holocene |- | Galeras lava dome || Colombia || Northern Volcanic Zone || Unknown || 2010 |- | Katla lava dome || Iceland || Iceland hotspot || Rhyolite || 1999 onwards<ref>[https://volcanism.wordpress.com/2010/03/04/eyjafjallajokull-and-katla-restless-neighbours/ Eyjafjallajökull and Katla: restless neighbours]</ref>{{Better source needed|date=April 2020}} |- | Lassen Peak || United States || Cascade Volcanic Arc || Dacite || 1917 |- | Black Butte (Siskiyou County, California) || United States || Cascade Volcanic Arc ||Dacite|| 9500 BP<ref name="VW_Shasta">{{cite web | url=https://volcano.oregonstate.edu/shasta | title=Shasta | publisher=Oregon State University | work=Volcano World | date=2000 | access-date=30 April 2020}}</ref> |- | Bridge River Vent lava dome || Canada || Cascade Volcanic Arc || Dacite || ca. 300 BC |- |La Soufrière lava dome |Saint Vincent and the Grenadines |Lesser Antilles Volcanic Arc | |2021<ref>{{Cite web|title=Soufrière St. Vincent volcano (West Indies, St. Vincent): twice length and volume of new lava dome since last update|url=https://www.volcanodiscovery.com/soufriere-st-vincent/news/125255/Soufriere-St-Vincent-volcano-West-Indies-St-Vincent-twice-length-and-volume-of-new-lava-dome-since-l.html|access-date=2021-04-08|website=www.volcanodiscovery.com}}</ref> |- | Mount Merapi lava dome || Indonesia || Sunda Arc || Unknown || 2010 |- | Nea Kameni || Greece || South Aegean Volcanic Arc || Dacite || 1950 |- | Novarupta lava dome || United States || Aleutian Arc || Rhyolite || 1912 |- | Nevados de Chillán lava domes || Chile || Southern Volcanic Zone || Dacite || 1986 |- | Puy de Dôme || France || Chaîne des Puys || Trachyte || {{Circa|5760 BC}} |- | Santa María lava dome || Guatemala || Central America Volcanic Arc || Dacite || 2009 |- | Sollipulli lava dome || Chile || Southern Volcanic Zone || Andesite to Dacite || 1240 ± 50 years |- | Soufrière Hills lava dome || Montserrat || Lesser Antilles || Andesite || 2009 |- | Mount St. Helens lava domes || United States || Cascade Volcanic Arc || Dacite || 2008 |- | Torfajökull lava dome || Iceland || Iceland hotspot || Rhyolite || 1477 |- | Tata Sabaya lava domes || Bolivia || Andes || Unknown || ~ Holocene |- | Tate-iwa || Japan || Japan Arc || Dacite || Miocene<ref>{{cite journal|last1=Goto|first1=Yoshihiko|last2=Tsuchiya|first2=Nobutaka|title=Morphology and growth style of a Miocene submarine dacite lava dome at Atsumi, northeast Japan|journal=Journal of Volcanology and Geothermal Research|date=July 2004|volume=134|issue=4|pages=255–275|doi=10.1016/j.jvolgeores.2004.03.015|bibcode=2004JVGR..134..255G}}</ref> |- | Tatun lava domes || Taiwan || || Andesite || 648<ref>{{cite web | title=Tatun Volcanic Group | website=Global Volcanism Program, Smithsonian Institution | date=2023-10-11 | url=https://volcano.si.edu/volcano.cfm?vn=281032 | access-date=2023-11-27}}</ref> |- | Valles lava domes || United States || Jemez Mountains || Rhyolite || 50,000-60,000 BP |- | Wizard Island lava dome || United States || Cascade Volcanic Arc || Rhyodacite<ref>[https://volcanoes.usgs.gov/volcanoes/crater_lake/crater_lake_geo_hist_136.html ''Map of Post-Caldera Volcanism and Crater Lake''] {{Webarchive|url=https://web.archive.org/web/20200804041331/https://volcanoes.usgs.gov/volcanoes/crater_lake/crater_lake_geo_hist_136.html |date=2020-08-04 }} USGS Cascades Volcano Observatory. Retrieved 2014-01-31.</ref> || 2850 BC |}

==References== {{Reflist}}

==External links== {{Commons category multi|Lava domes|Lava coulées}} * [http://www.volcano.si.edu/education/tpgallery.cfm?category=Lava%20Domes Global Volcanism Program: Lava Domes] * [https://volcanoes.usgs.gov/images/pglossary/LavaDome.php USGS Photo glossary of volcano terms: Lava dome]

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Category:Lava domes Category:Volcanic landforms