Sunset crater is a cinder cone that erupted about 1, years ago. Supervolcano eruptions are extremely rare in Earth history. A supervolcano must erupt more than 1, cubic km cubic miles of material, compared with 1. Helens or 25 km 3 for Mount Pinatubo, a large eruption in the Philippines in Not surprisingly, supervolcanoes are the most dangerous type of volcano.
Supervolcanoes are a fairly new idea in volcanology. The exact cause of supervolcano eruptions is still debated. However, scientists think that a very large magma chamber erupts entirely in one catastrophic explosion. This creates a huge hole or caldera into which the surface collapses Figure below.
Yellowstone sits above a hotspot that has erupted catastrophically three times: 2. Yellowstone has produced many smaller but still enormous eruptions more recently Figure below. The Yellowstone hotspot has produced enormous felsic eruptions.
The Yellowstone caldera collapsed in the most recent super eruption. Long Valley had an extremely hot and explosive rhyolite about , years ago. An earthquake swarm in alerted geologists to the possibility of a future eruption, but the quakes have since calmed down.
Unlike Mount Mazama, the Deception volcano is still active. The Deception volcano experienced a violent eruption roughly 10, years ago that caused its summit to collapse and flood with seawater, forming a caldera about 7 kilometers 4. The caldera gives the island its unique horseshoe shape, which opens to the sea through a narrow channel.
Shield volcano calderas do not result from singular explosive eruptions. They instead subside in gradual stages, due to the episodic release of lava. This less-explosive release of lava, known as lava fountain ing, is characteristic of shield volcanoes. As a shield volcano periodic ally releases lava, it produces nested or terrace d depressions rather than a large bowl-shaped caldera.
As a result, shield volcano calderas are usually less than 5 kilometers 3. Composed of dormant and active shield volcanoes, the islands of Hawaii have a number of impressive shield volcano calderas.
In total, the caldera complex has an area of roughly 15 square kilometers 6 square miles and reaches a depth of meters feet. Fernandina Island, the most volcanically active island in the chain, has a deep elliptical caldera that measures 4-by 6. In , a massive volcanic eruption produced one of the largest caldera collapses in recent history.
Like most shield volcano calderas, Fernandina caldera collapsed incremental ly and asymmetric ally, sinking in as much as meters 1, feet in some parts.
Resurgent caldera s are the largest volcanic structures on Earth, ranging from 15 to kilometers 9 to 62 miles in diameter.
They are not associated with one particular volcano, but instead result from the widespread collapse of vast magma chambers. This caldera collapse is produced by incredibly destructive eruptions known as pyroclastic sheet flows, the likes of which have not occurred in historic times.
The Toba Caldera on the Indonesian island of Sumatra is the newest resurgent caldera, created roughly 74, years ago by the largest volcanic eruption in the last 25 million years. This massive eruption eject ed 2, cubic kilometers 1, cubic miles of debris. The eruption left a caldera kilometers 62 miles long, 29 kilometers 18 miles wide, and meters 1, feet deep, making it the largest volcanic structure on Earth.
The caldera is now home to Lake Toba and Samosir Island. Samosir was formed by the uplift of the caldera floor due to magma pressure below. This uplift is common to all resurgent calderas as new magma fills in the empty magma chamber over thousands of years. This enormous volcano complex last erupted about , years ago.
Others include the Erta Al caldera in Ethiopia, the summit caldera of Piton del la Fournaise on Reunion Island, and the spectacular basaltic calderas on the shield volcanoes of the Galapagos Islands. Most basaltic shield volcano calderas on earth are km in diameter. Those observed on Mars, however, are extraordinarily large, the largest being the Olympus Mons caldera, with a diameter of more than 60 km!
Kilauea caldera Erta Al caldera Whereas Crater-Lake type calderas are associated with the explosive eruption felsic magma, generating voluminous pyroclastic sheet flows, basaltic calderas are not produced by such catastrophic events. Instead, they subside in increments to produce a nested structure of pits and terraces, as shown in the photos above for the Kilauea caldera and the Erta Al caldera.
Basaltic calderas like these are gradually enlarged by episodic collapse, due to the extraction of lava from shallow-level magma chambers underlying the summit areas. In some cases, the extraction of magma may occur through fractures that feed eruptions along the flanks of the shield volcano. Local collapse along such fractures can generate a linear system of pit craters that emanate away from many basaltic calderas and summit craters.
Photo by Vic Camp. Resurgent calderas are the largest volcanic structures on earth. They are associated with massive eruptions of voluminous pyroclastic sheet flows, on a scale not yet observed in historic times. The youngest of these resurgent calderas is the 74,year-old Toba Caldera on the Indonesian Island of Sumatra. The Toba eruption generated times more pyroclastic material than the moderate Plinian eruption of Mt.
Helens in ! There are three resurgent calderas in the United States less than 1. The term also includes the cone-shaped landform built by repeated eruptions over time. Teach your students about volcanoes with this collection of engaging material. A caldera is a depression created after a volcano partially collapses after releasing the majority of its magma chamber in an explosive eruption.
A volcano is a feature in Earth's crust where molten rock is squeezed out onto the Earth's surface. Along with molten rock, volcanoes also release gases, ash, and solid rock.
Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Image caldera Laguna de Quiltoa a caldera in Ecuador. Photograph by Obliot. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary.
Laguna de Quiltoa a caldera in Ecuador. Mount Mazama. Also known as a composite volcano. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
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