Lava dome

Volcán Chaitén-Sam Beebe-Ecotrust

Mono Crater closeup-1000px

Nea Kameni

MSH06 aerial crater from north high angle 09-12-06

MSH80 bulge on north side 04-27-80

Soufriere Hills Lava Dome Spire1

Lava dome or volcanic dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Lava domes are one of the several types of volcanic features formed by magmatic activity, and their formation is often associated with particular types of volcanic eruptions. Unlike the fluid lava flows produced in eruptions from Hawaiian and shield volcanoes, the lava that forms domes is more silica-rich and viscous, causing it to cool and solidify quickly. This results in the growth of a dome-shaped feature that can be highly explosive due to the trapped gases within the viscous magma.

Formation and Characteristics

Lava domes grow by endogenous and exogenous growth. In endogenous growth, the dome expands from within as new magma pushes up the dome's surface. Exogenous growth occurs as lava is expelled from a volcanic vent and piles up around it. The morphology of a lava dome can vary widely, from steep-sided spines to broad, flat-topped domes. The surface of a lava dome can be rough and blocky, as it is often made up of andesite, dacite, or rhyolite lava that breaks into blocks as it cools and moves.

Hazards

Lava domes pose significant volcanic hazards. The growth of a dome can lead to explosive eruptions if the dome becomes unstable or if the internal pressure from trapped gases becomes too great. Collapses of lava domes can result in deadly pyroclastic flows and lahars, which are rapid flows of volcanic debris and water. The 1902 eruption of Mount Pelée in Martinique, which resulted in the destruction of the town of Saint-Pierre and the death of over 30,000 people, is a tragic example of the destructive power of a collapsing lava dome.

Examples

Notable examples of lava domes include the Novarupta lava dome formed during the 1912 eruption in Alaska, the Unzen volcanic complex in Japan, which has been the site of several dome-forming eruptions over the past few centuries, and the Lassen Peak in California, which last erupted in 1915. These examples illustrate the diverse settings and scales at which lava domes can form.

Monitoring and Research

Monitoring lava domes is crucial for volcanic hazard assessment. Scientists use a variety of techniques to monitor domes, including seismology, ground deformation measurements, and satellite imagery. Research on lava domes also focuses on understanding the rheology (flow behavior) of viscous magmas and the dynamics of dome growth and collapse. This research helps to improve eruption forecasting and risk mitigation strategies in volcanic regions.