Yellowstone Caldera | |
---|---|
Highest point | |
Elevation | 9,203 [1] ft (2,805 m) |
Coordinates | 44°24′N110°42′W / 44.400°N 110.700°W |
Geography | |
Location | Yellowstone National Park, Wyoming, United States |
Parent range | Rocky Mountains |
Topo map | USGS Yellowstone National Park |
Geology | |
Rock age | 2,100,000–70,000 years [2] |
Mountain type(s) | Caldera [3] and supervolcano |
Volcanic field | Yellowstone Plateau |
Last eruption | Approximately 640,000 years ago (caldera-forming); 70,000 years ago (in the caldera) |
Climbing | |
Easiest route | Hike/auto/bus |
The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States. The caldera and most of the park are located in the northwest corner of the state of Wyoming. The caldera measures 43 by 28 miles (70 by 45 kilometers), and postcaldera lavas spill out a significant distance beyond the caldera proper. [4]
The caldera formed during the last of three supereruptions over the past 2.1 million years: the Huckleberry Ridge eruption 2.1 million years ago (which created the Island Park Caldera and the Huckleberry Ridge Tuff), the Mesa Falls eruption 1.3 million years ago (which created the Henry's Fork Caldera and the Mesa Falls Tuff), and the Lava Creek eruption approximately 640,000 years ago (which created the Yellowstone Caldera and the Lava Creek Tuff). [5]
The caldera was the largest known until the discovery of Apolaki Caldera in 2019, which is more than twice as wide. [6]
Volcanism at Yellowstone is relatively recent, with calderas created by large eruptions that took place 2.1 million, 1.3 million, and 640,000 years ago. The calderas lie over the Yellowstone hotspot under the Yellowstone Plateau where light and hot magma (molten rock) from the mantle rises toward the surface. The hotspot appears to move across terrain in the east-northeast direction, and is responsible for the eastern half of Idaho's Snake River Plain, but in fact the hotspot is much deeper than the surrounding terrain and remains stationary while the North American plate moves west-southwest over it. [7]
Over the past 16.5 million years or so, this hotspot has generated a succession of explosive eruptions and less violent floods of basaltic lava. Together these eruptions have helped create the eastern part of the Snake River Plain (to the west of Yellowstone) from a once-mountainous region. [8] At least a dozen of these eruptions were so massive that they are classified as supereruptions. Volcanic eruptions sometimes empty their stores of magma so swiftly that the overlying land collapses into the emptied magma chamber, forming a geographic depression called a caldera. [9]
The oldest identified caldera remnant straddles the border near McDermitt, Nevada–Oregon, although there are volcaniclastic piles and arcuate faults that define caldera complexes more than 60 km (37 mi) in diameter in the Carmacks Group of southwest-central Yukon, Canada, which are interpreted to have been formed 70 million years ago by the Yellowstone hotspot. [10] [11] Progressively younger volcanic units, most grouped in several overlapping volcanic fields, extend from the Nevada–Oregon border through the eastern Snake River Plain and terminate in the Yellowstone Plateau. One such field, the Bruneau-Jarbidge volcanic field in southern Idaho, was formed between 10 and 12 million years ago, and the event dropped ash to a depth of one foot (30 cm) 1,000 miles (1,600 km) away in northeastern Nebraska and killed large herds of rhinoceroses, camels, and other animals at Ashfall Fossil Beds State Historical Park. The United States Geological Survey (USGS) estimates there are one or two major caldera-forming eruptions and a hundred or so lava extruding eruptions per million years, and "several to many" steam eruptions per century. [12]
The loosely defined term "supervolcano" has been used to describe volcanic fields that produce exceptionally large volcanic eruptions. Thus defined, the Yellowstone Supervolcano is the volcanic field that produced the latest three supereruptions from the Yellowstone hotspot; it also produced one additional smaller eruption, thereby creating the West Thumb of Yellowstone Lake [13] 174,000 years ago. The three supereruptions occurred 2.1 million, 1.3 million, and approximately 640,000 years ago, forming the Island Park Caldera, the Henry's Fork Caldera, and Yellowstone calderas, respectively. [14] The Island Park Caldera supereruption (2.1 million years ago), which produced the Huckleberry Ridge Tuff, was the largest, and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption. The next biggest supereruption formed the Yellowstone Caldera (640,000 years ago) and produced the Lava Creek Tuff. The Henry's Fork Caldera (1.2 million years ago) produced the smaller Mesa Falls Tuff, but is the only caldera from the Snake River Plain–Yellowstone hotspot that is plainly visible today. [15]
Non-explosive eruptions of lava and less-violent explosive eruptions have occurred in and near the Yellowstone caldera since the last supereruption. [16] [17] The most recent lava flow occurred about 70,000 years ago, while a violent eruption excavated the West Thumb of Lake Yellowstone 174,000 years ago. Smaller steam explosions occur as well. An explosion 13,800 years ago left a 5 km (3.1 mi) diameter crater at Mary Bay on the edge of Yellowstone Lake (located in the center of the caldera). [18] [2] Currently, volcanic activity is exhibited via numerous geothermal vents scattered throughout the region, including the famous Old Faithful Geyser, plus recorded ground-swelling indicating ongoing inflation of the underlying magma chamber.[ citation needed ]
The volcanic eruptions, as well as the continuing geothermal activity, are a result of a great plume of magma located below the caldera's surface. The magma in this plume contains gases that are kept dissolved by the immense pressure under which the magma is contained. If the pressure is released to a sufficient degree by some geological shift, then some of the gases bubble out and cause the magma to expand. This can cause a chain reaction. If the expansion results in further relief of pressure, for example, by blowing crust material off the top of the chamber, the result is a very large gas explosion.[ citation needed ]
According to analysis of earthquake data in 2013, the magma chamber is 80 km (50 mi) long and 20 km (12 mi) wide. It also has 4,000 km3 (960 cu mi) underground volume, of which 6–8% is filled with molten rock. This is about 2.5 times bigger than scientists had previously imagined; however, scientists believe that the proportion of molten rock in the chamber is too low to allow for another supereruption. [19] [20] [21]
In October 2017, research from Arizona State University indicated prior to Yellowstone's last supereruption, magma surged into the magma chamber in two large influxes. An analysis of crystals from Yellowstone's lava showed that prior to the last supereruption, the magma chamber underwent a rapid increase in temperature and change in composition. The analysis indicated that Yellowstone's magma reservoir can reach eruptive capacity and trigger a super-eruption within just decades, not centuries as volcanologists had originally thought. [22] [23]
In respect of it being "well-known for its past explosive volcanic eruptions and lava flows as well for its world class hydrothermal system", the International Union of Geological Sciences (IUGS) included "The Yellowstone volcanic and hydrothermal system" in its assemblage of 100 geological heritage sites around the world in a listing published in October 2022. The organization defines an IUGS Geological Heritage Site as "a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history". [24]
The source of the Yellowstone hotspot is controversial. Some geoscientists hypothesize that the Yellowstone hotspot is the effect of an interaction between local conditions in the lithosphere and upper mantle convection. [25] [26] Others suggest an origin in the deep mantle (mantle plume). [27] Part of the controversy is the relatively sudden appearance of the hotspot in the geologic record. Additionally, the Columbia Basalt flows appeared at the same approximate time in the same place, prompting speculation that they share a common origin. As the Yellowstone hotspot traveled to the east and north, the Columbia disturbance moved northward and eventually subsided. [28]
An alternate theory to the mantle plume model was proposed in 2018. It is suggested that the volcanism may be caused by upwellings from the lower mantle resulting from water-rich fragments of the Farallon plate descending from the Cascadia subduction region, sheared off at a subducted spreading rift. [29]
Others suggest that the mantle plume could not have been a dominant force in Yellowstone volcanism due to the sinking Farallon plate, as it acts as a buffer that breaks apart the plume. Any heat from the plume that does make it to the surface is limited. [30] [31]
Volcanic and tectonic actions in the region cause between 1,000 and 2,000 measurable earthquakes annually. Most are relatively minor, measuring magnitude 3 or weaker. Occasionally, numerous earthquakes are detected in a relatively short period of time, an event known as an earthquake swarm. In 1985, more than 3,000 earthquakes were measured over a period of several months. More than 70 smaller swarms were detected between 1983 and 2008. The USGS states these swarms are likely caused by slips on pre-existing faults rather than by movements of magma or hydrothermal fluids. [33] [34]
In December 2008, continuing into January 2009, more than 500 earthquakes were detected under the northwest end of Yellowstone Lake over a seven-day span, with the largest registering a magnitude of 3.9. [35] [36] Another swarm started in January 2010, after the Haiti earthquake and before the Chile earthquake. With 1,620 small earthquakes between January 17, 2010, and February 1, 2010, this swarm was the second-largest ever recorded in the Yellowstone Caldera. The largest of these shocks was a magnitude 3.8 that occurred on January 21, 2010. [34] [37] This swarm subsided to background levels by February 21. On March 30, 2014, at 6:34 AM MST, a magnitude 4.8 earthquake struck Yellowstone, the largest recorded there since February 1980. [38] In February 2018, more than 300 earthquakes occurred, with the largest being a magnitude 2.9. [39]
The Lava Creek eruption of the Yellowstone Caldera, which occurred 640,000 years ago, [40] ejected approximately 1,000 cubic kilometres (240 cu mi) of rock, dust and volcanic ash into the atmosphere. [2] It was Yellowstone's third and most recent caldera-forming eruption.
Geologists closely monitor the elevation of the Yellowstone Plateau, which has been rising as quickly as 150 millimetres (5.9 in) per year, as an indirect measurement of changes in magma chamber pressure. [41] [42] [43]
The upward movement of the Yellowstone caldera floor between 2004 and 2008—almost 75 millimetres (3.0 in) each year—was more than three times greater than ever observed since such measurements began in 1923. [44] From 2004 to 2008, the land surface within the caldera moved upward as much as 8 inches (20 cm) at the White Lake GPS station. [45] [46] In January 2010, the USGS stated that "uplift of the Yellowstone Caldera has slowed significantly" [47] and that uplift continues but at a slower pace. [48] USGS, University of Utah and National Park Service scientists with the Yellowstone Volcano Observatory maintain that they "see no evidence that another such cataclysmic eruption will occur at Yellowstone in the foreseeable future. Recurrence intervals of these events are neither regular nor predictable." [2] This conclusion was reiterated in December 2013 in the aftermath of the publication of a study by University of Utah scientists finding that the "size of the magma body beneath Yellowstone is significantly larger than had been thought". The Yellowstone Volcano Observatory issued a statement on its website stating:
Although fascinating, the new findings do not imply increased geologic hazards at Yellowstone, and certainly do not increase the chances of a 'supereruption' in the near future. Contrary to some media reports, Yellowstone is not 'overdue' for a supereruption. [49]
Media reports were more hyperbolic in their coverage. [50]
A study published in GSA Today, the monthly news and science magazine of the Geological Society of America, identified three fault zones where future eruptions are most likely to be centered. [51] Two of those areas are associated with lava flows aged 174,000–70,000 years ago, and the third is a focus of present-day seismicity. [51]
In 2017, NASA conducted a study to determine the feasibility of preventing the volcano from erupting. The results suggested that cooling the magma chamber by 35 percent would be enough to forestall such an incident. NASA proposed introducing water at high pressure 10 kilometers underground. The circulating water would release heat at the surface, possibly in a way that could be used as a geothermal power source. If enacted, the plan would cost about $3.46 billion. Brian Wilcox of the Jet Propulsion Laboratory observes that such a project could incidentally trigger an eruption if the top of the chamber is drilled into. [52] [53]
Studies and analysis may indicate that the greater hazard comes from hydrothermal activity which occurs independently of volcanic activity.[ citation needed ] Over 20 large craters have been produced in the past 14,000 years, resulting in such features as Mary Bay, Turbid Lake, and Indian Pond, which was created in an eruption about 1300 BC.[ citation needed ]
In a 2003 report, USGS researchers proposed that an earthquake may have displaced more than 77 million cubic feet (2,200,000 m3; 580,000,000 US gal) of water in Yellowstone Lake, creating colossal waves that unsealed a capped geothermal system and led to the hydrothermal explosion that formed Mary Bay. [54] [55]
Further research shows that very distant earthquakes reach and have effects upon the activities at Yellowstone, such as the 1992 7.3 magnitude Landers earthquake in California's Mojave Desert that triggered a swarm of quakes from more than 800 miles (1,300 km) away, and the 2002 7.9 magnitude Denali fault earthquake 2,000 miles (3,200 km) away in Alaska that altered the activity of many geysers and hot springs for several months afterward. [56]
In 2016, the USGS announced plans to map the subterranean systems responsible for feeding the area's hydrothermal activity. According to the researchers, these maps could help predict when another eruption occurs. [57]
A caldera is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the structural integrity of such a chamber, greatly diminishing its capacity to support its own roof, and any substrate or rock resting above. The ground surface then collapses into the emptied or partially emptied magma chamber, leaving a large depression at the surface. Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Compared to the thousands of volcanic eruptions that occur over the course of a century, the formation of a caldera is a rare event, occurring only a few times within a given window of 100 years. Only eight caldera-forming collapses are known to have occurred between 1911 and 2018, with a caldera collapse at Kīlauea, Hawaii in 2018. Volcanoes that have formed a caldera are sometimes described as "caldera volcanoes".
Lake Toba is a large natural lake in North Sumatra, Indonesia, occupying the caldera of the Toba supervolcano. The lake is located in the middle of the northern part of the island of Sumatra, with a surface elevation of about 900 metres (2,953 ft), the lake stretches from 2.88°N 98.52°E to 2.35°N 99.1°E. The lake is about 100 kilometres long, 30 kilometres (19 mi) wide, and up to 505 metres (1,657 ft) deep. It is the largest lake in Indonesia and the largest volcanic lake in the world. Toba Caldera is one of twenty geoparks in Indonesia, and was recognised in July 2020 as one of the UNESCO Global Geoparks.
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.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism.
Long Valley Caldera is a depression in eastern California that is adjacent to Mammoth Mountain. The valley is one of the Earth's largest calderas, measuring about 20 mi (32 km) long (east-west), 11 mi (18 km) wide (north-south), and up to 3,000 ft (910 m) deep.
Newberry Volcano is a large, active, shield-shaped stratovolcano located about 20 miles (32 km) south of Bend, Oregon, United States, 35 miles (56 km) east of the major crest of the Cascade Range, within the Newberry National Volcanic Monument. Its highest point is Paulina Peak. Newberry is the largest volcano in the Cascade Volcanic Arc, with an area of 1,200 square miles (3,100 km2) when its lava flows are taken into account. From north to south, the volcano has a length of 75 miles (121 km), with a width of 27 miles (43 km) and a total volume of approximately 120 cubic miles (500 km3). It was named for the geologist and surgeon John Strong Newberry, who explored central Oregon for the Pacific Railroad Surveys in 1855.
Kamaʻehuakanaloa Seamount is an active submarine volcano about 22 mi (35 km) off the southeast coast of the island of Hawaii. The top of the seamount is about 3,200 ft (975 m) below sea level. This seamount is on the flank of Mauna Loa, the largest active subaerial shield volcano on Earth. Kamaʻehuakanaloa is the newest volcano in the Hawaiian–Emperor seamount chain, a string of volcanoes that stretches about 3,900 mi (6,200 km) northwest of Kamaʻehuakanaloa. Unlike most active volcanoes in the Pacific Ocean that make up the active plate margins on the Pacific Ring of Fire, Kamaʻehuakanaloa and the other volcanoes of the Hawaiian–Emperor seamount chain are hotspot volcanoes and formed well away from the nearest plate boundary. Volcanoes in the Hawaiian Islands arise from the Hawaii hotspot, and as the youngest volcano in the chain, Kamaʻehuakanaloa is the only Hawaiian volcano in the deep submarine preshield stage of development.
Kverkfjöll is a potentially active central volcano, fissure swarm, and associated mountain range situated on the northern border of the glacier Vatnajökull in Iceland.
The Phlegraean Fields is a large caldera volcano west of Naples, Italy. It is part of the Campanian volcanic arc, which includes Mount Vesuvius, about 9 km east of Naples. The Phlegraean Fields is monitored by the Vesuvius Observatory. It was declared a regional park in 2003.
The Anahim Volcanic Belt (AVB) is a west–east trending chain of volcanoes and related magmatic features in British Columbia, Canada. It extends from Athlone Island on the Central Coast, running eastward through the strongly uplifted and deeply dissected Coast Mountains to near the community of Nazko on the Interior Plateau. The AVB is delineated as three west-to-east segments that differ in age and structure. A wide variety of igneous rocks with differing compositions occur throughout these segments, comprising landforms such as volcanic cones, volcanic plugs, lava domes, shield volcanoes and intrusions.
The Yellowstone hotspot is a volcanic hotspot in the United States responsible for large scale volcanism in Idaho, Montana, Nevada, Oregon, and Wyoming, formed as the North American tectonic plate moved over it. It formed the eastern Snake River Plain through a succession of caldera-forming eruptions. The resulting calderas include the Island Park Caldera, Henry's Fork Caldera, and the Bruneau-Jarbidge caldera. The hotspot currently lies under the Yellowstone Caldera. The hotspot's most recent caldera-forming supereruption, known as the Lava Creek Eruption, took place 640,000 years ago and created the Lava Creek Tuff, and the most recent Yellowstone Caldera. The Yellowstone hotspot is one of a few volcanic hotspots underlying the North American tectonic plate; another example is the Anahim hotspot.
The Lava Creek Tuff is a voluminous sheet of ash-flow tuff located in Wyoming, Montana and Idaho, United States. It was created during the Lava Creek eruption around 630,000 years ago, which led to the formation of the Yellowstone Caldera. This eruption is considered the climactic event of Yellowstone's third volcanic cycle. The Lava Creek Tuff covers an area of more than 7,500 km2 (2,900 sq mi) centered around the caldera and has an estimated magma volume of 1,000 km3 (240 cu mi).
La Garita Caldera is a large caldera and extinct supervolcano in the San Juan volcanic field in the San Juan Mountains around the town of Creede in southwestern Colorado, United States. It is west of La Garita, Colorado. The eruption that created the La Garita Caldera is among the largest known volcanic eruptions in Earth's history, as well as being one of the most powerful known supervolcanic events.
The Yellowstone Plateau Volcanic Field, also known as the Yellowstone Supervolcano or the Yellowstone Volcano, is a complex volcano, volcanic plateau and volcanic field located mostly in the western U.S. state of Wyoming, but it also stretches into Idaho and Montana. It is a popular site for tourists.
Volcanic activity is a major part of the geology of Canada and is characterized by many types of volcanic landform, including lava flows, volcanic plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes, and maars, along with less common volcanic forms such as tuyas and subglacial mounds.
The Anahim hotspot is a hypothesized hotspot in the Central Interior of British Columbia, Canada. It has been proposed as the candidate source for volcanism in the Anahim Volcanic Belt, a 300 kilometres long chain of volcanoes and other magmatic features that have undergone erosion. This chain extends from the community of Bella Bella in the west to near the small city of Quesnel in the east. While most volcanoes are created by geological activity at tectonic plate boundaries, the Anahim hotspot is located hundreds of kilometres away from the nearest plate boundary.
The Hawaiʻi hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the Hawaiian–Emperor seamount chain, a 6,200-kilometer (3,900 mi) mostly undersea volcanic mountain range. Four of these volcanoes are active, two are dormant; more than 123 are extinct, most now preserved as atolls or seamounts. The chain extends from south of the island of Hawaiʻi to the edge of the Aleutian Trench, near the eastern coast of Russia.
A series of small volcanic earthquakes measuring less than 4.0 on the Richter magnitude scale took place in the sparsely populated Nazko area of the Central Interior of British Columbia, Canada, from October 9, 2007, to June 12, 2008. They occurred just west of Nazko Cone, a small tree-covered cinder cone that last erupted about 7,200 years ago.
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.
A popularized scientific look at the Yellowstone area's geological past and potential future.
A novel looking at an eruption in the Yellowstone Caldera written by a practicing Wyoming geologist. Contains a wealth of technical details on the geology of western Wyoming.