Resurgent dome

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The caldera of Lake Toba, with a resurgent dome, forming Samosir Island. Toba zoom.jpg
The caldera of Lake Toba, with a resurgent dome, forming Samosir Island.

In geology, a resurgent dome is a dome formed by swelling or rising of a caldera floor due to movement in the magma chamber beneath it. Unlike a lava dome, a resurgent dome is not formed by the extrusion of highly viscous lava onto the surface, but rather by the uplift and deformation of the surface itself by magma movement underground. Resurgent domes are typically found near the center of very large open calderas such as Yellowstone Caldera or Valles Caldera, and in turn such calderas are often referred to as "resurgent-type" calderas to distinguish them from the more common (but much smaller) calderas found on shield volcanoes and stratovolcanoes.

The structure that makes a resurgent dome possible is a fracture zone made up of ring faults surrounded by concentric normal faults around the outside of the rings. During initial formation of the caldera these ring faults provide vents for ash-flow eruptions and are the point at which subsidence of the cauldron block occurs. Subsequent magma flows then push the cauldron block back up creating the dome. [1]

In the monitoring of volcanic hazards, resurgent domes are often intensively monitored, as an ongoing increase in elevation accompanied by seismic activity is certain evidence for magma rising beneath the surface.

Examples of calderas with resurgent domes

Related Research Articles

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<span class="mw-page-title-main">Lake Toba</span> Crater lake located in Sumatra, Indonesia

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<span class="mw-page-title-main">Ring of Fire</span> Region around the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur

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<span class="mw-page-title-main">Taupō Volcanic Zone</span> Active volcanic zone in New Zealand

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<span class="mw-page-title-main">Yellowstone Caldera</span> Volcanic caldera in Yellowstone National Park in the United states

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<span class="mw-page-title-main">Complex volcano</span> Landform of more than one related volcanic centre

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<span class="mw-page-title-main">Timeline of volcanism on Earth</span>

This timeline of volcanism on Earth includes a list of major volcanic eruptions of approximately at least magnitude 6 on the Volcanic explosivity index (VEI) or equivalent sulfur dioxide emission during the Quaternary period. Other volcanic eruptions are also listed.

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<span class="mw-page-title-main">Laguna del Maule (volcano)</span> Volcanic field in the Andes mountain range, Chile

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<span class="mw-page-title-main">Pastos Grandes</span>

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Vilama is a Miocene caldera in Bolivia and Argentina. Straddling the border between the two countries, it is part of the Central Volcanic Zone, one of the four volcanic belts in the Andes. Vilama is remote and forms part of the Altiplano-Puna volcanic complex, a province of large calderas and associated ignimbrites that were active since about 8 million years ago, sometimes in the form of supervolcanoes.

<span class="mw-page-title-main">Monowai (seamount)</span> Volcanic seamount north of New Zealand

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References

  1. Smith, R. L.; Bailey, R. A. (1968). "Resurgent cauldrons". In Coats, R. R.; Hay, R. L.; Anderson, C. A. (eds.). Studies in Volcanology : A memoir in honor of Howell Williams. Geological Society of America Memoir. Vol. 116. pp. 613–662. OCLC   3006.