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In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow Extrusive rock of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. (2025). 9780123859389, Elsevier. ISBN 9780123859389 Around 6% of eruptions on Earth form lava domes. 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). The characteristic dome shape is attributed to high viscosity that prevents the lava from lava flow very far. This high viscosity can be obtained in two ways: by high levels of silicon dioxide in the magma, or by degasification of fluid magma. Since viscous and andesitic domes weathering 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, e.g. the Martian surface in the western part of Arcadia Planitia and within Terra Sirenum.
Lava domes grow by Endogeny dome growth or exogeny 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. 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. Lava spine and Lava are common extrusive products of lava domes. 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. If part of a lava dome collapses and exposes pressurized magma, can be produced. Other hazards associated with lava domes are the destruction of property from Lava, , and triggered from re-mobilization of loose ash and debris. Lava domes are one of the principal structural features of many 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. 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.
landslide of a lava dome can produce a block and ash flow. (2025). 9780123859389, Academic Press. ISBN 9780123859389
The world's largest known dacite flow is the Cerro Chao, a huge coulée flow-dome between two volcanoes in northern Chile. This flow is over long, has obvious flow features like pressure ridges, and a flow front tall (the dark scalloped line at lower left). Chao dacite dome complex at NASA Earth Observatory There is another prominent coulée flow on the flank of Llullaillaco volcano, in Argentina, Coulées! by Erik Klemetti, an assistant professor of Geosciences at Denison University. and other examples in the Andes.
| + Lava domes
! Name of lava dome !! Country !! Volcanic area !! Composition !! Last eruption or growth episode | ||||
| 2009 | ||||
| Pleistocene | ||||
| Holocene | ||||
| 2010 | ||||
| 1999 onwards Eyjafjallajökull and Katla: restless neighbours | ||||
| 1917 | ||||
| 9500 BP | ||||
| ca. 300 BC | ||||
| La Soufrière lava dome | Saint Vincent and the Grenadines | Lesser Antilles Volcanic Arc | 2021 | |
| 2010 | ||||
| 1950 | ||||
| 1912 | ||||
| 1986 | ||||
| 2009 | ||||
| 1240 ± 50 years | ||||
| 2009 | ||||
| 2008 | ||||
| 1477 | ||||
| ~ Holocene | ||||
| Miocene | ||||
| 648 | ||||
| 50,000-60,000 Before Present | ||||
| 2850 BC |
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