The Cascade Volcanic Arc is a chain of volcanoes stretching from southern British Columbia down to northern California. Within the arc there is a variety of stratovolcanoes like Mount Rainier and broad shield volcanoes like Medicine Lake. But calderas are very rare in the Cascades, with very few forming over the 39 million [1] year lifespan of the arc.
The few eruptions that do form calderas rarely make it into the VEI 7 range, staying confined to the VEI 6 range in most cases. The only volcanoes known to have produced eruptions within the VEI 7 range are Crater Lake, the Mt. Baker Volcanic Field, and the Lassen Volcanic Center.
All of the exceptionally large caldera-forming eruptions within the cascades erupted silica-rich magmas, with the three VEI 7s erupting mainly rhyodacite and rhyolite.
Volcano | Caldera Name | Caldera Size | Age | Eruption Unit Name | Magma Volume (km3) | Tephra Volume (km3) | VEI | Notes | Reference(s) |
---|---|---|---|---|---|---|---|---|---|
Silverthrone | Silverthrone caldera | 20 km wide | <1,100,000 | N/A | N/A | N/A | Poorly studied | [2] | |
Franklin Glacier Complex | N/A | 6 x 20 km | <6,800,000 | N/A | N/A | N/A | Poorly studied | [3] | |
Coquihalla Volcanic Complex | N/A | 6 x 6 km | <21,400,000 | N/A | N/A | 50 | Tephra volume does not represent a single eruption | [4] [5] | |
Hannegan | Hannegan caldera | 8 x 3.5 km | 3,722,000 | Ignimbrite of Hannegan Peak | N/A | N/A | 6-7 | Trap-door caldera, first collapse. Both ignimbrites have a combined magma volume of 127 km3 | [6] |
3,720,000 | Ignimbrite of Ruth Mountain | N/A | N/A | 6-7 | Trap-door caldera, second collapse | [6] | |||
Big Bosom Buttes | Big Bosom caldera | 4 x 5 km ? | Oligocene | N/A | N/A | N/A | Poorly studied | [6] | |
Mount Rahm ? | Mount Rahm caldera | N/A | Oligocene | N/A | N/A | N/A | Poorly studied | [6] | |
Mount Baker Volcanic Field | Kulshan Caldera | 4.5 x 8 km | 1,149,000 | Lake Tapps tephra | 124 | N/A | 7 | [7] [8] | |
Gamma Ridge ? | Gamma Ridge caldera | N/A | 1,242,000 | N/A | 40 | N/A | 6-7 | Poorly studied, trap-door caldera | [9] |
Mount Aix Volcanic Complex | Mount Aix caldera | 6 x 9 | 28,000,000 | Bumping River tuff-north | N/A | N/A | 6-7 | Cummalitave volume of Mt. Aix tuffs exceeds 100 km3 | [10] [6] |
25,000,000 | Bumping River tuff-east | N/A | N/A | 6-7 | [10] | ||||
25,000,000 | Cash Prairie tuffs | N/A | N/A | 6-7 | [10] | ||||
Goat Rocks | Devils Horns caldera | 5 x 8 km | 3,200,000 | N/A | N/A | >60 | 6 | Tephra volume may represent multiple eruptions | [11] [6] |
Newberry | Newberry Crater | 6.4 x 8 km | 80,000 | Olema ash | 14-22 | N/A | 6 | Second caldera formation | [9] |
230,000 | Tepee Draw tuff | 10 | 25 | 6 | First caldera formation | [12] [9] | |||
Mount Mazama | Crater Lake | 8 x 10 km | 5783 BCE | Mazama ash | 61 | 176 | 7 | Largest Holocene eruption in the arc | [13] [14] [12] |
29,900 | Trego Hot Springs | 8 | 20.8 | 6 | [15] [12] | ||||
Medicine Lake | Medicine Lake caldera | 7 x 12 km | 171,000 | Antelope Well tuff | 20 | N/A | 6 | [9] | |
Lassen Volcanic Center | Rockland caldera | N/A | 610,000 | Rockland tephra | 130 | 326.7 | 7 | [15] [12] |
These are places that have experienced very large eruptions of ash and ignimbrite that reached a VEI of 6 or greater, but have no documented calderas.
The Tumalo Volcanic Center is a volcano located just east of Bend, Oregon. It started producing large eruptions around 650,000 years ago, with its first eruption reaching a 5 on the VEI scale and erupting more than 1 km3 of magma. [12] The volcano would go on to produce at least three more voluminous eruptions. The two largest eruptions ejected more than 5 km3 of magma. [12] Eruptions of those sizes usually entail caldera collapses. [16] However no calderas have been identified in this area.
Between 6.25 to 5.45 million years ago the cascade volcanic arc flared up in activity. [16] Producing far more explosive ignimbrite eruptions than usual. The activity was mostly focused within the central Oregon cascades. Over 78 individual eruptions have been identified and the total volume of pyroclastic products in the Deschutes formation is estimated to be between 400 and 675 km3. [17]
A supervolcano is a volcano that has had an eruption with a volcanic explosivity index (VEI) of 8, the largest recorded value on the index. This means the volume of deposits for such an eruption is greater than 1,000 cubic kilometers.
The Taupō Volcanic Zone (TVZ) is a volcanic area in the North Island of New Zealand that has been active for at least the past two million years and is still highly active. Mount Ruapehu marks its south-western end and the zone runs north-eastward through the Taupō and Rotorua areas and offshore into the Bay of Plenty. It is part of the larger Central Volcanic Region that extends further westward through the western Bay of Plenty to the eastern side of the Coromandel Peninsula and has been active for four million years. At Taupō the rift volcanic zone is widening east–west at the rate of about 8 mm per year while at Mount Ruapehu it is only 2–4 mm per year but this increases at the north eastern end at the Bay of Plenty coast to 10–15 mm per year. It is named after Lake Taupō, the flooded caldera of the largest volcano in the zone, the Taupō Volcano and contains a large central volcanic plateau as well as other landforms associated with its containing tectonic intra-arc continental Taupō Rift.
Novarupta is a volcano that was formed in 1912, located on the Alaska Peninsula on a slope of Trident Volcano in Katmai National Park and Preserve, about 290 miles (470 km) southwest of Anchorage. Formed during the largest volcanic eruption of the 20th century, Novarupta released 30 times the volume of magma of the 1980 eruption of Mount St. Helens.
Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.
The Oruanui eruption of New Zealand's Taupō Volcano was the world's most recent supereruption, and largest phreatomagmatic eruption characterised to date.
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.
The magma supply rate measures the production rate of magma at a volcano. Global magma production rates on Earth are about 20–25 cubic kilometres per year (4.8–6.0 cu mi/a).
Panizos is a Late Miocene caldera in the Potosí Department of Bolivia and the Jujuy Province of Argentina. It is part of the Altiplano-Puna volcanic complex of the Central Volcanic Zone in the Andes. 50 volcanoes active in recent times are found in the Central Volcanic Zone, and several major caldera complexes are situated in the area. The caldera is located in a difficult-to-access part of the Andes.
Laguna Amarga is a caldera and associated ignimbrite in the Andes of northwestern Argentina.
The Kulshan caldera is a Pleistocene volcano in the North Cascades of Washington and one of the few calderas identified in the entire Cascade Range. It is the product of the Mount Baker volcanic field, which has a history stretching back to possibly 3.722 million years ago.
Lunar Crater volcanic field is a volcanic field in Nye County, Nevada. It lies along the Reveille and Pancake Ranges and consists of over 200 vents, mostly small volcanic cones with associated lava flows but also several maars, including one maar named Lunar Crater. Some vents have been eroded so heavily that the structures underneath the volcanoes have been exposed. Lunar Crater itself has been used as a testing ground for Mars rovers and as training ground for astronauts.
The Whakamaru Caldera was created in a massive supereruption 335,000 years ago and is approximately 30 by 40 km in size and is located in the North Island of New Zealand. It now contains active geothermal areas as well as the later Maroa Caldera.
The Haroharo Caldera is a 26 by 16 km postulated volcanic feature in Taupō Volcanic Zone of the North Island, New Zealand within the larger and older Ōkataina Caldera. Since 2010 further studies have tended to use the terms Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera to the features assigned to it. However the name is used in the peer reviewed literature to summarise and group these features based on gravitational and magnetic features.
The Mangakino caldera complex is the westernmost and one of oldest extinct rhyolitic caldera volcanoes in the Taupō Volcanic Zone of New Zealand's North Island. It produced about a million years ago in the Kidnappers eruption of 1,200 km3 (287.9 cu mi), the most widespread ignimbrite deposits on Earth being over 45,000 km2 (17,000 sq mi) and was closely followed in time by the smaller 200 km3 (48.0 cu mi) Rocky Hill eruption. The Kidnappers eruption had a estimated VEI of 8 and has been assigned a total eruption volume of 2,760 km3 (662.2 cu mi).
Ōkataina Caldera is a volcanic caldera and its associated volcanoes located in Taupō Volcanic Zone of New Zealand's North Island. It has several actual or postulated sub calderas. The Ōkataina Caldera is just east of the smaller Rotorua Caldera and southwest of the much smaller Rotomā Embayment which is usually regarded as an associated volcano. It shows high rates of explosive rhyolitic volcanism although its last eruption was basaltic. The postulated Haroharo Caldera contained within it has sometimes been described in almost interchangeable terms with the Ōkataina Caldera or volcanic complex or centre and by other authors as a separate complex defined by gravitational and magnetic features.. Since 2010 other terms such as the Haroharo vent alignment, Utu Caldera, Matahina Caldera, Rotoiti Caldera and a postulated Kawerau Caldera are often used, rather than a Haroharo Caldera classification.
Hannegan caldera is a 3.72 million year old volcanic collapse structure in the North Cascades of the U.S. state of Washington. The caldera collapsed during two separate volcanic eruptions that produced as much as 140 km3 of rhyolite ash.
Much of the volcanic activity in the northern portions of the North Island of New Zealand is recent in geological terms and has taken place over the last 30 million years. This is primarily due to the North Island's position on the boundary between the Indo-Australian and Pacific Plates, a part of the Pacific Ring of Fire, and particularly the subduction of the Pacific Plate under the Indo-Australian Plate. The activity has included some of the world's largest eruptions in geologically recent times and has resulted in much of the surface formations of the North Island being volcanic as shown in the map.
The Rotoiti Caldera is a postulated, mainly infilled sub caldera of the Ōkataina Caldera based upon gravitational and magnetic evidence. It erupted 100 cubic kilometres (24 cu mi) of magma that is used in the recent stratigraphy of much of the northern North Island. It was formed in the larger paired eruption with the lesser Earthquake Flat vents linked by tectonic interaction across the length of the Ōkataina Caldera. The series of eruptions was about 50,000 years ago, with the resulting widespread Rotoiti ignimbrite and several layers of Rotoiti/Rotoehu tephra/brecca/ash giving challenges in consistent dating. It was subsequently infilled by later eruptive activity to a depth of over 2 km (1.2 mi). The paired eruptions may have erupted about 240 cubic kilometres (58 cu mi) of tephra.