query: when was the last time yellowstone caldera erupted

pos: Yellowstone Caldera (which created the Henry's Fork Caldera and the Mesa Falls Tuff); and the Lava Creek eruption approximately 630,000 years ago (which created the Yellowstone Caldera and the Lava Creek Tuff). Volcanism at Yellowstone is relatively recent, with calderas that were created during large eruptions that took place 2.1 million, 1.3 million, and 630,000 years ago. The calderas lie over a hotspot where light and hot magma (molten rock) from the mantle rises toward the surface. While the Yellowstone hotspot is now under the Yellowstone Plateau, it did help to create the eastern Snake River Plain (to the west of Yellowstone)

pos: Yellowstone Caldera that produce exceptionally large volcanic eruptions. Thus defined, the Yellowstone Supervolcano is the volcanic field which produced the latest three supereruptions from the Yellowstone hotspot; it also produced one additional smaller eruption, thereby creating the West Thumb of Yellowstone Lake 174,000 years ago. The three supereruptions occurred 2.1 million, 1.3 million, and approximately 630,000 years ago, forming the Island Park Caldera, the Henry's Fork Caldera, and Yellowstone calderas, respectively. 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

neg: Caldera in the form of a "resurgent dome" such as is seen at Cerro Galán, Lake Toba, Yellowstone, etc., by subsequent intrusion of magma. A "silicic" or "rhyolitic caldera" may erupt hundreds or even thousands of cubic kilometers of material in a single event. Even small caldera-forming eruptions, such as Krakatoa in 1883 or Mount Pinatubo in 1991, may result in significant local destruction and a noticeable drop in temperature around the world. Large calderas may have even greater effects. When Yellowstone Caldera last erupted some 650,000 years ago, it released about 1,000 km of material (as measured in dense rock

neg: Yellowstone National Park Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand archaeological sites. Yellowstone National Park spans an area of , comprising lakes, canyons, rivers and mountain ranges. Yellowstone Lake is one of the largest high-elevation lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent. The caldera is considered an active volcano. It has erupted with tremendous force several times in the last two million years. Half of the world's geysers and hydrothermal features are in Yellowstone, fueled by this

neg: Geothermal areas of Yellowstone basin is Great Fountain Geyser, whose eruptions reach in the air, while waves of water cascade down its sinter terraces. The West Thumb Geyser Basin , including Potts Basin to the north, is the largest geyser basin on the shores of Yellowstone Lake. The heat source of the thermal features in this location is thought to be relatively close to the surface, only 10,000 feet (3,000 m) down. West Thumb is about the same size as another famous volcanic caldera, Crater Lake in Oregon, but much smaller than the great Yellowstone Caldera which last erupted about 640,000 years ago. West

neg: Yellowstone hotspot years ago. The Yellowstone Plateau volcanic field is composed of four adjacent calderas. West Thumb Lake is itself formed by a smaller caldera which erupted 174,000 years ago. (See .) The Henry's Fork Caldera in Idaho was formed in an eruption of more than 1.3 million years ago, and is the source of the Mesa Falls Tuff. The Henry's Fork Caldera is nested inside of the Island Park Caldera and the calderas share a rim on the western side. The earlier Island Park Caldera is much larger and more oval and extends well into Yellowstone Park. Although much smaller than

neg: Yellowstone Plateau the present Yellowstone Plateau and culminated 630,000 years ago with the eruption of the Lava Creek Tuff and the formation of the present caldera. Resurgent doming then occurred at both the NE and SW sides of the caldera and voluminous intracaldera rhyolitic lava flows were erupted between 150,000 and 70,000 years ago. Phreatic eruptions produced local tephras during the early Holocene. The caldera presently contains one of the world's largest hydrothermal systems including the world's largest concentration of geysers. Much of the plateau is located within Yellowstone National Park. Yellowstone Plateau The Yellowstone Plateau volcanic field is a geological feature

neg: Yellowstone Caldera feeding the area's hydrothermal activity. According to the researchers, these maps could help predict when another supereruption occurs. Yellowstone Caldera The Yellowstone Caldera is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States, sometimes referred to as the Yellowstone Supervolcano. The caldera and most of the park are located in the northwest corner of Wyoming. The major features of the caldera measure about 34 by 45 miles (55 by 72 km). 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

neg: Global catastrophic risk the past 17 million years. A massive volcano eruption would eject extraordinary volumes of volcanic dust, toxic and greenhouse gases into the atmosphere with serious effects on global climate (towards extreme global cooling: volcanic winter if short-term, and ice age if long-term) or global warming (if greenhouse gases were to prevail). When the supervolcano at Yellowstone last erupted 640,000 years ago, the thinnest layers of the ash ejected from the caldera spread over most of the United States west of the Mississippi River and part of northeastern Mexico. The magma covered much of what is now Yellowstone National Park and

neg: Bruneau-Jarbidge caldera basaltic component. Bruneau-Jarbidge caldera The Bruneau-Jarbidge caldera (sometimes called a supervolcano) is located in present-day southwest Idaho. The volcano erupted during the Miocene, between ten and twelve million years ago, spreading a thick blanket of ash in the Bruneau-Jarbidge event and forming a caldera. Animals were suffocated and burned in pyroclastic flows within a hundred miles of the event, and died of slow suffocation and starvation much farther away, notably at Ashfall Fossil Beds, located 1,000 miles downwind in northeastern Nebraska, where up to two meters of ash were deposited. At the time, the caldera was above the Yellowstone hotspot.

neg: Bruneau-Jarbidge caldera Bruneau-Jarbidge caldera The Bruneau-Jarbidge caldera (sometimes called a supervolcano) is located in present-day southwest Idaho. The volcano erupted during the Miocene, between ten and twelve million years ago, spreading a thick blanket of ash in the Bruneau-Jarbidge event and forming a caldera. Animals were suffocated and burned in pyroclastic flows within a hundred miles of the event, and died of slow suffocation and starvation much farther away, notably at Ashfall Fossil Beds, located 1,000 miles downwind in northeastern Nebraska, where up to two meters of ash were deposited. At the time, the caldera was above the Yellowstone hotspot. By its

neg: Yellowstone hotspot and Picabo volcanic fields were active about 10 million years ago. The Picabo Caldera was notable for producing the Arbon Valley Tuff 10.2 million years ago. The Heise volcanic field of eastern Idaho produced explosive caldera-forming eruptions which began 6.6 million years ago and lasted for more than 2 million years, sequentially producing four large-volume rhyolitic eruptions. The first three caldera-forming rhyolites — Blacktail Tuff, Walcott Tuff and Conant Creek Tuff — totaled at least 2250 km of erupted magma. The final, extremely voluminous, caldera-forming eruption — the Kilgore Tuff — which erupted 1800 km of ash, occurred 4.5 million

neg: Yellowstone Caldera Yellowstone Caldera The Yellowstone Caldera is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States, sometimes referred to as the Yellowstone Supervolcano. The caldera and most of the park are located in the northwest corner of Wyoming. The major features of the caldera measure about 34 by 45 miles (55 by 72 km). 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

neg: Yellowstone hotspot Caldera is sometimes referred to as the First Phase Yellowstone Caldera or the Huckleberry Ridge Caldera. The youngest of the hotspot calderas, the Yellowstone Caldera, formed 640,000 years ago and is about 34 miles (55 km) by 45 miles (72 km) wide. Non-explosive eruptions of lava and less-violent explosive eruptions have occurred in and near the Yellowstone Caldera since the last super eruption. The most recent lava flow occurred about 70,000 years ago, while the largest violent eruption excavated the West Thumb of Lake Yellowstone around 150,000 years ago. Smaller steam explosions occur as well – an explosion 13,800 years

neg: Yellowstone Caldera eruption. The next biggest supereruption formed the Yellowstone Caldera (~ 630,000 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. Non-explosive eruptions of lava and less-violent explosive eruptions have occurred in and near the Yellowstone caldera since the last supereruption. The most recent lava flow occurred about 70,000 years ago, while a violent eruption excavated the West Thumb of Lake Yellowstone around 150,000 years ago. Smaller steam explosions occur as well:

neg: Complex volcano are widespread in the Precambrian rocks of northern New Mexico, which indicates that caldera complexes have been important for much of Earth's history. Yellowstone National Park is on three partly covered caldera complexes. The Long Valley Caldera in eastern California is also a complex volcano; the San Juan Mountains in southwestern Colorado are formed on a group of Neogene-age caldera complexes, and most of the Mesozoic and Cenozoic rocks of Nevada, Idaho, and eastern California are also caldera complexes and their erupted ash flow tuffs. The Bennett Lake Caldera in British Columbia and the Yukon Territory is another example of

neg: Volcano temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupo in New Zealand; Lake Toba in Sumatra, Indonesia; and Ngorongoro Crater in Tanzania. Because of the enormous area they may cover, supervolcanoes are hard to identify centuries after an eruption. Similarly, large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted (even though the lava flow

neg: Yellowstone National Park North America. A subsequent caldera-forming eruption occurred about 160,000 years ago. It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake. Since the last supereruption, a series of smaller eruptive cycles between 640,000 and 70,000 years ago, has nearly filled in the Yellowstone Caldera with 80 different eruptions of rhyolitic lavas such as those that can be seen at Obsidian Cliffs and basaltic lavas which can be viewed at Sheepeater Cliff. Lava strata are most easily seen at the Grand Canyon of the Yellowstone, where the Yellowstone River continues to carve into the ancient lava flows.

neg: Yellowstone hotspot Caldera, are interpreted to have formed during a short interval 16.5–15.5 million years ago, in the waning stage of the Steens flood basalt volcanism. The northwest Nevada calderas have diameters ranging from 15–26 km and deposited high temperature rhyolite ignimbrites over approximately 5000 km. The Bruneau-Jarbidge caldera erupted between ten and twelve million years ago, spreading a thick blanket of ash in the Bruneau-Jarbidge event and forming a wide caldera. Animals were suffocated and burned in pyroclastic flows within a hundred miles of the event, and died of slow suffocation and starvation much farther away, notably at Ashfall Fossil Beds,

neg: Yellowstone Caldera 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. This swarm reached the 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. In February 2018, more than 300 earthquakes occurred, with the largest being a magnitude 2.9. The last full-scale eruption of the Yellowstone Supervolcano, the Lava Creek

neg: Yellowstone hotspot Yellowstone hotspot The Yellowstone hotspot is a volcanic hotspot in the United States responsible for large scale volcanism in Idaho, Montana, Nevada, Oregon, and Wyoming 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, the 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.

neg: Medicine Lake Volcano is believed that the Medicine Lake volcano is unique, having many small magma chambers rather than one large one. Medicine Lake is in the caldera of the volcano, which measures . The caldera may have formed by collapse after a large volume of andesite was erupted from vents along the caldera rim. The distribution of late Pleistocene vents, mostly concentrated along the rim, suggests that ring faults already existed when most of the andesite erupted. No single large eruption has been related to caldera formation. The only eruption recognized to have produced ash flow tuff occurred in late Pleistocene time,

neg: Yellowstone National Park The canyon is a classic V-shaped valley, indicative of river-type erosion rather than erosion caused by glaciation. Each eruption is part of an eruptive cycle that climaxes with the partial collapse of the roof of the volcano's partially emptied magma chamber. This creates a collapsed depression, called a caldera, and releases vast amounts of volcanic material, usually through fissures that ring the caldera. The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600,000 to 800,000 years, but the small number of such climactic eruptions cannot be used to make an accurate prediction for future

neg: Henry's Fork Caldera Henry's Fork Caldera The Henry's Fork Caldera in eastern Idaho is a caldera located an area known as Island Park, west of Yellowstone National Park. The caldera was formed by an eruption 1.3 million years ago of the Yellowstone hotspot, that had a volume of and is the source of the Mesa Falls Tuff. The Henry's Fork Caldera is nested inside of the Island Park Caldera, and the calderas share a rim on the western side. The earlier Island Park Caldera is much larger and more oval and extends well into Yellowstone Park. Although much smaller than the Island Park

neg: Island Park Caldera Henry's Fork Caldera, which is the source of the Mesa Falls Tuff. It was formed 1.3 Ma in an eruption of more than . The two nested calderas share the same rim on their western sides, but the older Island Park Caldera is much larger and more oval and extends well into Yellowstone National Park. The Island Park Caldera is sometimes referred to as the First Phase Yellowstone Caldera or the Huckleberry Ridge Caldera. To the southwest of the caldera lies the Snake River Plain, which was formed by a succession of older calderas marking the path of the Yellowstone

neg: Hotspot (geology) crust, which melts to form rhyolites. These rhyolites can form violent eruptions. For example, the Yellowstone Caldera was formed by some of the most powerful volcanic explosions in geologic history. However, when the rhyolite is completely erupted, it may be followed by eruptions of basaltic magma rising through the same lithospheric fissures (cracks in the lithosphere). An example of this activity is the Ilgachuz Range in British Columbia, which was created by an early complex series of trachyte and rhyolite eruptions, and late extrusion of a sequence of basaltic lava flows. The hotspot hypothesis is now closely linked to the

neg: Plinian eruption type are defined by ash plumes over high and a volume of erupted material to in size. Eruptions in the ultra-Plinian category include the Lava Creek eruption of the Yellowstone Caldera (approx 640,000 years ago, VEI 8), Lake Toba (approx 74000 years ago, VEI 8), Tambora (1815, VEI 7), Krakatoa (1883, VEI 6), Akahoya eruption of Kikai Caldera, Japan, and the 1991 Mount Pinatubo eruption in the Philippines (VEI 6). Plinian eruption 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

neg: Global catastrophic risk extended beyond, covering much of the ground from Yellowstone River in the east to the Idaho falls in the west, with some of the flows extending north beyond Mammoth Springs. According to a recent study, if the Yellowstone caldera erupted again as a supervolcano, an ash layer one to three millimeters thick could be deposited as far away as New York, enough to "reduce traction on roads and runways, short out electrical transformers and cause respiratory problems". There would be centimeters of thickness over much of the U.S. Midwest, enough to disrupt crops and livestock, especially if it happened at

neg: Yellowstone National Park the active part of a hotspot that has moved northeast over time. The origin of this hotspot volcanism is disputed. One theory holds that a mantle plume has caused the Yellowstone hotspot to migrate northeast, while another theory explains migrating hotspot volcanism as the result of the fragmentation and dynamics of the subducted Farallon Plate in Earth's interior. The Yellowstone Caldera is the largest volcanic system in North America. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions. The magma chamber that lies under Yellowstone is estimated to be a single connected chamber,

neg: Coranzulí (caldera) erupted in three distinct flows, the last one is the largest one and has the highest matrix component. This ignimbrite is of rhyodacitic composition. The Las Termas ignimbrite contains pumice and is highly welded and crystalline. A wide caldera was left by the eruption that formed this ignimbrite and postcaldera volcanism generated three thick dacitic lava flows within it. The Cerro Coranzuli lava dome was erupted subsequently. A major seismic velocity anomaly is found beneath Coranzuli volcano. Coranzulí (caldera) Coranzuli is a back-arc caldera in the Andes, related to the Altiplano-Puna volcanic complex. It formed along the Lipez geological lineament

neg: Yellowstone Lake high under a section of Yellowstone Lake, where there are a variety of faults, hot springs and small craters. Seismic imaging has recently shown that sediment layers are tilted, but how old this feature is has not yet been established. After the magma chamber under the Yellowstone area collapsed 640,000 years ago in its previous great eruption, it formed a large caldera that was later partially filled by subsequent lava flows (see Yellowstone Caldera). Part of this caldera is the basin of Yellowstone Lake. The original lake was higher than the present-day lake, extending northward across Hayden Valley to the

neg: Yellowstone hotspot the Island Park Caldera, the Henry's Fork Caldera is still sizeable at long and wide and its curved rim is plainly visible from many locations in the Island Park area. Of the many calderas formed by the Yellowstone Hotspot, including the later Yellowstone Caldera, the Henry's Fork Caldera is the only one that is currently clearly visible. The Henry's Fork of the Snake River flows through the Henry's Fork Caldera and drops out at Upper and Lower Mesa Falls. The caldera is bounded by the Ashton Hill on the south, Big Bend Ridge and Bishop Mountain on the west, by

neg: Tuff hot at the time of deposition to weld together. Strictly speaking, if the rock contains scattered, pea-sized fragments or fiamme in it, it is called a welded lapilli-tuff. Welded tuffs (and welded lapilli-tuffs) can be of fallout origin, or deposited from pyroclastic density currents, as in the case of ignimbrites. During welding, the glass shards and pumice fragments adhere together (necking at point contacts), deform, and compact together, resulting in a eutaxitic fabric. Welded ignimbrites can be highly voluminous, such as the Lava Creek tuff erupted from Yellowstone Caldera in Wyoming 640,000 years ago. Lava Creek tuff is known to

neg: Geothermal areas of Yellowstone Thumb is a caldera within a caldera. West Thumb was created approximately 162,000 years ago when a magma chamber bulged up under the surface of the earth and subsequently cracked it along ring fracture zones. This in turn released the enclosed magma as lava and caused the surface above the emptied magma chamber to collapse. Water later filled the collapsed area of the caldera, forming an extension of Yellowstone Lake. This created the source of heat and water that feed the West Thumb Geyser Basin today. The thermal features at West Thumb are not only found on the lake shore,

neg: Yellowstone Volcano Observatory the VHP Alert Page. Individuals can receive automated updates through the Volcano Notification Service. In 2005, a BBC/Discovery docudrama entitled Supervolcano was released on cable television. The drama imagines the reaction of the Yellowstone Volcano Observatory to a super eruption at the Yellowstone Caldera. Producer Ailsa Orr credits YVO scientists as inspiration for the film's three primary characters. The YVO Scientist-in-Charge reflected on the hype associated with volcanism at Yellowstone in a 2005 magazine article. Yellowstone Volcano Observatory The Yellowstone Volcano Observatory (YVO) is a volcano observatory that monitors the Yellowstone Caldera in Yellowstone National Park in the United States.

neg: Island Park, Idaho an elevation of above sea level, making it the highest city in Idaho. According to the United States Census Bureau, the city has a total area of , of which, is land and is water. The area was known as Island Park long before the -long town was incorporated. The area known as Island Park is mostly a large crater or caldera named the Henry's Fork Caldera that was created by the same hotspot that created the earlier Island Park Caldera and the later Yellowstone Caldera. Although much smaller than either the Island Park Caldera or the Yellowstone Caldera, the

neg: Yellowstone hotspot ago left a 5 kilometer diameter crater at Mary Bay on the edge of Yellowstone Lake. Both the Heise and Yellowstone volcanic fields produced a series of caldera-forming eruptions characterised by magmas with so-called "normal" oxygen isotope signatures (with heavy oxygen-18 isotopes) and a series of predominantly post-caldera magmas with so-called "light" oxygen isotope signatures (characterised as low in heavy oxygen-18 isotopes). The final stage of volcanism at Heise was marked by "light" magma eruptions. If Heise is any indication, this could mean that the Yellowstone Caldera has entered its final stage, but the volcano might still exit with a

neg: Greater Yellowstone Ecosystem Greater Yellowstone Ecosystem The Greater Yellowstone Ecosystem (GYE) is one of the last remaining large, nearly intact ecosystems in the northern temperate zone of the Earth. It is located within the northern Rocky Mountains, in areas of northwestern Wyoming, southwestern Montana, and eastern Idaho, and is about 18 million acres. Yellowstone National Park and the Yellowstone Caldera 'hotspot' are within it. Conflict over ecological and resource management has been controversial, and the area is a flagship site among conservation groups that promote ecosystem management. The Greater Yellowstone Ecosystem (GYE) is one of the world's foremost natural laboratories in landscape ecology

neg: Caldera equivalent (DRE)), covering a substantial part of North America in up to two metres of debris. By comparison, when Mount St. Helens erupted in 1980, it released ~1.2 km (DRE) of ejecta. The ecological effects of the eruption of a large caldera can be seen in the record of the Lake Toba eruption in Indonesia. About 74,000 years ago, this Indonesian volcano released about dense-rock equivalent of ejecta. This was the largest known eruption during the ongoing Quaternary period (the last 2.6 million years) and the largest known explosive eruption during the last 25 million years. In the late 1990s,

neg: McDermitt Caldera McDermitt Caldera The McDermitt Caldera is a large, oval-shaped caldera west of McDermitt in southeastern Oregon and northern Nevada in the United States. It is about wide north to south and wide east to west. The western part of the caldera is in the Trout Creek Mountains, and the northern part is in the Oregon Canyon Mountains. McDermitt Caldera is possibly the oldest caldera in a sequence of calderas formed by the Yellowstone Hotspot. The caldera was formed when a lava dome made of rhyolite collapsed in an eruption between 16.37 and 16.41 million years ago. The lava dome had

neg: Cosigüina Cosigüina Cosigüina (also spelt Cosegüina) is a stratovolcano located in the western part of Nicaragua. It forms a large peninsula extending into the Gulf of Fonseca. The summit is truncated by a large caldera, 2 x 2.4 km in diameter and 500 m deep, holding a substantial crater lake (Laguna Cosigüina). This cone has grown within an earlier caldera, forming a somma volcano. The earlier caldera rim is still exposed on the north side, but has been buried by the younger cone elsewhere. The volcano last erupted in 1859, but its most famous activity occurred on January 20, 1835, when

neg: Timeline of volcanism on Earth Yellowstone Caldera, Henry's Fork Caldera, Island Park Caldera, Heise Volcanic Field had all Yellowstone hotspot as magma source. 2.588 ± 0.005 million years BP, the Quaternary period and Pleistocene epoch begin. Approximately 5.332 million years BP, the Pliocene epoch begins. Most eruptions before the Quaternary period have an unknown VEI. Approximately 23.03 million years BP, the Neogene period and Miocene epoch begin. The global dimming through volcanism (ash aerosol and sulfur dioxide) is quite independent of the eruption VEI. When sulfur dioxide (boiling point at standard state: -10 °C) reacts with water vapor, it creates sulfate ions (the precursors to

neg: Henry's Fork Caldera Caldera, the Henry's Fork Caldera is still sizeable at long and wide and its curved rim is plainly visible from many locations in the Island Park area. Of the many calderas formed by the Yellowstone hotspot, including the later Yellowstone Caldera, the Henry's Fork Caldera is the only one that is currently clearly visible. It is one of a succession of supervolcanoes and calderas that formed the Snake River Plain. The Henrys Fork of the Snake River flows through the Henry's Fork Caldera and drops out at Upper and Lower Mesa Falls. The caldera is bounded by the Ashton Hill

neg: Coso Volcanic Field as a few days. This kind of brisk and robust seismic activity is common in volcanic areas, such as Long Valley Caldera located near Mammoth Lakes, and Yellowstone Caldera at Yellowstone. The Coso Volcanic Field shows stunning examples of volcanic activity, probably last active 30,000 to 40,000 years ago, but ash emission and small cone building episodes may be Holocene (>10,000 years) in age. Eerkens, Jelmer W. and Jeffrey S. Rosenthal. 2004. Are Obsidian Subsources Meaningful Units of Analysis?: Temporal and Spatial Patterning of Subsources in the Coso Volcanic Field, Southeastern California. "Journal of Archaeological Science" 31:21–29. Elston, Robert G.

neg: Trou au Natron Trou au Natron Trou au Natron (French: "hole of natron") or Doon Orei (Teda: "big hole") is a volcanic caldera of the Tibesti Massif in the nation of Chad in Northern Africa. The volcano is extinct. It is unknown when it last erupted. Its volcano number is 0205–01. Trou au Natron is located just south-east of Toussidé, the westernmost volcano of the Tibesti Mountains. Its edge cuts into the nearby Yirrigue caldera. The caldera sits at an elevation of . It has an irregular diameter of approximately and is up to deep. Four smaller volcanic cones, made of scoria or

neg: Yellowstone hotspot climactic fourth caldera event analogous to the fourth and final caldera-forming eruption of Heise (the Kilgore Tuff) – which was also made up of so-called "light" magmas. The appearance of "light" magmas would seem to indicate that the uppermost portion of the continental crust has largely been consumed by the earlier caldera- forming events, exhausting the melting potential of the crust above the mantle plume. In this case Yellowstone could be expiring. It could be another 1–2 million years (as the North American Plate moves across the Yellowstone hotspot) before a new supervolcano is born to the northeast, and the

neg: Yellowstone Caldera eruption which happened approximately 640,000 years ago, ejected approximately of rock, dust and volcanic ash into the sky. Geologists are closely monitoring the rise and fall of the Yellowstone Plateau, which has been rising as quickly as per year, as an indication of changes in magma chamber pressure. The upward movement of the Yellowstone caldera floor between 2004 and 2008—almost each year—was more than three times greater than ever observed since such measurements began in 1923. From 2004 to 2008, the land surface within the caldera moved upward as much as at the White Lake GPS station. By the end

neg: La Pacana the caldera, where breccia deposits occur within the Atana ignimbrite. Some of the magma that gave rise to the Atana ignimbrite was erupted after the ignimbrite; the lava domes formed after the caldera collapse were generated by this magma. This category of dependent postcaldera volcanism includes Corral de Coquena and Morro Negro; other postcaldera volcanic centres have different compositions and thus probably formed from different sources than the Atana magma. Ignimbrite eruptions continued after the formation of the caldera. The Filo Delgado ignimbrite was erupted at some time during the Pliocene from the Huailitas volcano. Its volume is about .

neg: Yellowstone Plateau Yellowstone Plateau The Yellowstone Plateau volcanic field is a geological feature found in the U.S. state of Wyoming. It is a popular site for tourists. The plateau developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions. Eruption of the > Huckleberry Ridge Tuff about 2 million years ago created the more than long Island Park Caldera. The second cycle concluded with the eruption of the Mesa Falls Tuff around 1.3 million years ago, forming the wide Henry's Fork Caldera at the western end of the first caldera. Activity subsequently shifted to

neg: Caldera Caldera A caldera is a large cauldron-like hollow that forms following the evacuation of a magma chamber/reservoir. When large volumes of magma are erupted over a short time, structural support for the crust above the magma chamber is lost. The ground surface then collapses downward into the partially emptied magma chamber, leaving a massive depression at the surface (from one to dozens of kilometers in diameter). 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. Only seven known caldera-forming collapses have

neg: Yellowstone Caldera of 2009, the uplift had slowed significantly and appeared to have stopped. In January 2010, the USGS stated that "uplift of the Yellowstone Caldera has slowed significantly" and that uplift continues but at a slower pace. The U.S. Geological Survey, 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." This conclusion was reiterated in December 2013 in the aftermath of the publication of a study by University

neg: Aguas Calientes caldera Calientes caldera erupted twice dacitic ignimbrites. was the source of two major ignimbrites; the Tajamar Ignimbrite (including the Chorrillos Ignimbrite inside the caldera), and the Verde Ignimbrite. The first was erupted 10.5–10.1 Ma and is a body of ignimbrite of about . The second was erupted 17.2 Ma and has a volume of . The Abra de Gallo ignimbrite was formerly considered the third and erupted 10.0-10.5 Ma; Petrinovic "et al." consider it part of the Tajamar ignimbrite. Both eruptions probably resulted from a disruption of the magma chamber integrity by vertical faults created through the activity of horizontal fault

neg: Avachinsky new cone inside the caldera occurred in two major eruption phases, 18,000 and 7,000 years ago. In his Journal of Captain Cook's Last Voyage, John Ledyard records the eruption of Avachinsky on June 15, 1779. He refers to Koryaksky and Avachinsky as Peter and Paul. Avachinsky has erupted at least 16 times in recorded history. Eruptions have generally been explosive, and pyroclastic flows and lahars have tended to be directed to the south west by the breached caldera. The most recent large eruption (VEI=4) occurred in 1945, when about 0.25 km³ of magma was ejected. The volcano has since had

neg: Yellowstone Caldera 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. 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 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. Progressively younger caldera remnants, most grouped in several overlapping volcanic fields, extend from the Nevada–Oregon border through the eastern Snake River Plain and terminate in

neg: Yellowstone Caldera the Yellowstone Plateau. One such caldera, the Bruneau-Jarbidge caldera 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) away in northeastern Nebraska and killed large herds of rhinoceros, camel, 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 100 or so lava extruding eruptions per million years, and "several to many" steam eruptions per century. The loosely defined term "supervolcano" has been used to describe volcanic fields

neg: Yellowstone National Park of the Yellowstone caldera. Beginning on April 30, 2007, 16 small earthquakes with magnitudes up to 2.7 occurred in the Yellowstone Caldera for several days. These swarms of earthquakes are common, and there have been 70 such swarms between 1983 and 2008. In December 2008, over 250 earthquakes were measured over a four-day span under Yellowstone Lake, the largest measuring a magnitude of 3.9. In January 2010, more than 250 earthquakes were detected over a two-day period. Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U.S. Geological Survey. On March

neg: Pacaya been the source of at least nine very large explosions over the past 300,000 years, erupting a total of about of magma. After the last caldera-forming eruption 23,000 years ago several smaller vents within and around the caldera have seen eruptive activity. Pacaya is the largest post-caldera volcano, and has been one of Central America's most active volcanoes over the last 500 years. It has erupted at least 23 times since the Spanish conquest, producing basalt and basaltic andesite. About 1,100 years ago, the volcano's edifice collapsed, causing a huge landslide. Deposits from the landslide travelled about from the volcano

neg: Mount Garibaldi which stretches over along the subduction zone. Several volcanoes in the arc are potentially active. Lassen Peak in California, which last erupted in 1921, is the southernmost historically active volcano in the arc, while the Mount Meager massif, just north of Mount Garibaldi, which erupted about 2,350 years ago, is generally considered the northernmost. A few isolated volcanic centres northwest of the Mount Meager massif, such as the Silverthrone Caldera, which is a circular wide, deeply dissected caldera complex, are considered by some geologists to be the northernmost member of the arc. Mount Garibaldi is the largest volcano in southernmost

neg: Cascade Volcanoes geological traits and history. Lassen Peak in California, which last erupted in 1917, is the southernmost historically active volcano in the arc, while the Mount Meager massif in British Columbia, which erupted about 2,350 years ago, is generally considered the northernmost member of the arc. A few isolated volcanic centers northwest of the Mount Meager massif such as the Silverthrone Caldera, which is a circular wide, deeply dissected caldera complex, may also be the product of Cascadia subduction because the igneous rocks andesite, basaltic andesite, dacite and rhyolite can also be found at these volcanoes as they are elsewhere along

neg: Newberry Volcano the last Ice Age about 12,000 years ago and 7,700 years ago, the volcano erupted at least 12 times. 7,700 years ago, Mount Mazama erupted, producing volcanic ash and pumice that accumulated to a thickness of up to on the Newberry Volcano, covering many of the lava flows on its slopes. During three eruptive periods at Newberry over the past 7,500 years, the caldera has seen rhyolitic eruptions from seven individual vents. About 7,000 years ago, eruptions occurred along the rift zone northwest of Newberry Volcano's caldera, yielding twelve lava flows that encompassed an area of . Around the same

neg: Bayonnaise Rocks Bayonnaise Rocks The rocks are the exposed portion of the western ridge of a submarine volcanic caldera, approximately in diameter at a depth of approximately . The above sea-level portion has a surface area of approximately 0.01 square kilometers, with a summit height of . and consists of three large rocks and many smaller rocks. The caldera is known to have erupted in 1869-1871, 1896, 1906, 1915, 1934, 1946, 1952-1955, 1957-1960, and 1970. The last known submarine eruption of the caldera was in 1988, which discolored the local water. On the northeast rim of the same caldera to the east

neg: Caldera Io in 1979. Io has many calderas with diameters tens of kilometers across. Caldera A caldera is a large cauldron-like hollow that forms following the evacuation of a magma chamber/reservoir. When large volumes of magma are erupted over a short time, structural support for the crust above the magma chamber is lost. The ground surface then collapses downward into the partially emptied magma chamber, leaving a massive depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and

neg: Geology of New Zealand and caused 151 deaths at Tangiwai. The last significant eruption was 1995–96. Ngauruhoe last erupted 1973–75. Taranaki is a perfectly formed andesitic strato-volcano, that last erupted in 1755. Lake Taupo, the largest lake in the North Island, is a volcanic caldera, responsible for rhyolitic eruptions about once every 1,000 years. The largest eruption in the last 65,000 years was the cataclysmic Oruanui Eruption 26,500 years ago, producing 530 cubic kilometres of magma. The most recent eruption, around 233 AD was also a major event, the biggest eruption worldwide in the last 5,000 years. The eruption caused a pyroclastic flow that

neg: Wheelwright caldera between 5 and 4.8 million years ago, an unnamed secondary centre 3.9 ± 0.9 million years ago, Pico Wheelwright 5.9 ± 0.9 million years ago, Volcán de Inca 3.3 ± 0.3 million years ago, Volcan Rex erupted 4.9 ± 0.2 million years ago. This stage of volcanic activity was of andesitic to dacitic composition and became more silicic over time. At the closing of this stage, lava domes and associated pyroclastic flows were emplaced within the caldera and across the Cordillera Claudio Gay. Hydrothermal alteration processes gave rise to sulfur deposits. Wheelwright caldera Wheelwright caldera is a caldera in Chile.

neg: Chaitén (volcano) Chaitén (volcano) Chaitén is a volcanic caldera in diameter, west of the elongated ice-capped Michinmahuida volcano and northeast of the town of Chaitén, near the Gulf of Corcovado in southern Chile. The most recent eruptive phase of the volcano erupted on 2008. Originally, radiocarbon dating of older tephra from the volcano suggested that its last previous eruption was in 7420 BC ± 75 years. However, recent studies have found that the volcano is more active than thought. According to the Global Volcanism Program, its last eruption was in 2011. The caldera rim reaches above sea level. Before the current eruption,

neg: Chaitén (volcano) Chaitén eruption Photography Webcams Chaitén (volcano) Chaitén is a volcanic caldera in diameter, west of the elongated ice-capped Michinmahuida volcano and northeast of the town of Chaitén, near the Gulf of Corcovado in southern Chile. The most recent eruptive phase of the volcano erupted on 2008. Originally, radiocarbon dating of older tephra from the volcano suggested that its last previous eruption was in 7420 BC ± 75 years. However, recent studies have found that the volcano is more active than thought. According to the Global Volcanism Program, its last eruption was in 2011. The caldera rim reaches above sea level.

neg: Snake River Plain Calderas formed as the result of enormous rhyolite ignimbrite eruptions, with single eruptions producing up to of ash. Henry's Fork Caldera, measuring by , may be the largest symmetrical caldera in the world. The caldera formed when a dome of magma built up and then drained away. The center of the dome collapsed, leaving a caldera. Henry's Fork Caldera lies within the older and larger Island Park Caldera, which is by . Younger volcanoes that erupted after passing over the hotspot covered the plain with young basalt lava flows in places, including Craters of the Moon National Monument. The Snake

neg: Aguas Calientes caldera two major ignimbrites; the Tajamar Ignimbrite (including the Chorrillos Ignimbrite inside the caldera) and the Verde Ignimbrite. The first was erupted 10.5–10.1 Ma ago and is a body of ignimbrite of about . The second was erupted 17.2 Ma ago and has a volume of . Aguas Calientes caldera lies in the northwestern Salta Province of Argentina, in the San Antonio de los Cobres district to the southeast of the town of the same name. Aguas Calientes caldera is part of the Central Volcanic Zone (CVC), which is located in southern Peru, northern Chile, southwestern Bolivia and northwestern Argentina in

neg: Mount Katmai Katmai resulted in the collapse of the summit area, forming the caldera. Following the subsidence, a small dacitic lava dome known as Horseshoe Island was emplaced on the floor of the caldera; this is the only juvenile material erupted from Katmai caldera during the historical eruption. It was visible at the time of the expedition in 1916, but has since been submerged by the crater lake. Still, the eruption from Katmai had a VEI of 3, and possibly involved phreatic eruptions. In 1919, geologists noted a lake covering a large part of the caldera floor, but by 1923 the lake

neg: Wrangell–St. Elias National Park and Preserve Its last activity was about a million years ago, and it has been deeply eroded by glacial activity. Tanada Peak is an older and larger neighbor of Capital Mountain, tall with a by summit caldera. The shield volcano last erupted 900,000 years ago and has been dissected by glaciers. The Skookum Creek Volcano is a volcanic center that has been heavily eroded. It was active between 3.2 million and 2 million years ago. high at its highest point, the old shield volcano has been severely eroded. Its caldera is surrounded by a series of dacite and rhyolite domes. Mount Jarvis

neg: Lake Towada Lake Towada The lake is a popular tourist destination. Lake Towada occupies the caldera of an active volcano, with large scale volcanic eruptions occurring approximately 55,000, 25,000 and 13,000 years ago. The most recent eruption left traces of pyroclastic flows as far away as the modern city of Aomori. The lake is a double caldera in that the inlet between its two peninsulas (called the “Nakaumi”) is the remnant of a secondary caldera which erupted and collapsed approximately 5400 years ago. The mountain continued to erupt well into the historical period, with the last recorded eruption occurring in 915 AD,

neg: La Garita Caldera was erupted probably shortly before the Fish Canyon Tuff. The Pagosa Peak Dacite has been interpreted as having erupted as thick spatter during low-energy lava fountaining and has a volume of about . These rocks had been identified as lava because the unit has a high aspect ratio (1:50) and very high viscosity of the crystal-rich magma similar to those of flow-layered silicic lava. However, the Pagosa Peak Dacite formed by low-column pyroclastic fountaining and lateral transport as dense, poorly-inflated pyroclastic flows. La Garita Caldera La Garita Caldera is a large volcanic caldera in the San Juan volcanic field in

neg: Geology of Nicaragua crust. Structural geologists have grouped all the rock units as the Chortis Block. Volcanism remains active in Nicaragua. The Masaya Caldera Complex erupted 460,000 and 50,000 years ago with the Las Sierras Formation as a Pliocene-Pleistocene basement rock. Massive pyroclastic and ignimbrite eruptions caused the caldera to collapse although most of the material it erupted has been basalt. Analysis of an eruption of the caldera in 1772 indicates perhaps the highest rate of lava effusion in Central America. Another active volcano is the San Cristobal Volcanic Complex in the northwest, which erupted in the 1500s and 1600s and again at

neg: Brothers Volcano industry. The volcano was created by a subduction of the Pacific Plate under the Australian Plate. It is still unknown when the Brothers Volcano last erupted, but the crater walls tell us that its last eruption was so explosive that it caused the volcano to blow out a caldera. A joint expedition by the United States, New Zealand and Germany mapped the volcano in detail in 2007. Submarine volcanoes are not monitored by any organization, but have become a central interest in current expeditions. Brothers Volcano The Brothers Volcano is a Pacific Ocean submarine volcano in the Kermadec Arc, 340

neg: Yellowstone Caldera it to be; however, scientists believe that the proportion of molten rock in the chamber is much too low to allow another supereruption. 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. Others suggest an origin in the deep mantle (mantle plume). 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, causing speculation about their common

neg: Pastos Grandes Pastos Grandes Pastos Grandes is the name of a caldera and its crater lake in Bolivia. The caldera is part of the Altiplano-Puna volcanic complex, a large ignimbrite province that is part of the Central Volcanic Zone of the Andes. Pastos Grandes has erupted a number of ignimbrites through its history, some of which exceeded a volume of . After the ignimbrite phase, the lava domes of the Cerro Chascon-Runtu Jarita complex were erupted close to the caldera and along faults. The caldera is the site of a few lakes, some of which are fed by hot springs. A number

neg: 2012 (film) the city collapses and sinks into the Pacific Ocean, killing millions of residents. They fly to Yellowstone to retrieve a map from Charlie with the arks' location. As they leave, the Yellowstone Caldera erupts; Charlie is killed when he stays behind to cover the eruption. The group lands in Las Vegas to find a larger plane and meet Yuri, his twin sons Alec and Oleg, his girlfriend Tamara and their pilot Sasha. Sasha and Gordon fly them out in an Antonov An-500 as the Yellowstone ash cloud envelops Las Vegas. An attempted refueling stop in Hawaii is abandoned after seeing

neg: St. Francois Mountains Francois Mts. are interpreted to be a series of caldera complexes, similar in scale to the Yellowstone caldera complex. However, it is debated whether the igneous activity was related to a hotspot, like Yellowstone, or whether it was related to an ancient subduction zone. The St. Francois Mountains are the center of the Lead Belt, a mining region yielding lead, iron, baryte, zinc, silver, manganese, cobalt, and nickel ores. Historic Mine La Motte near Fredericktown was the site of lead mining activity by the French as early as 1720. The area today accounts for over 90% of primary lead production

neg: Lascar (volcano) were associated with a volatile phase that underwent extensive interaction with the future eruption products. The previous volcanic edifice was destroyed by this eruption, which may have formed a caldera. The vent was no wider than , as it is completely hidden beneath the western cone. Such a vent or caldera is substantially smaller than the volume of rocks erupted, a discrepancy that is also evident in the 1932 eruption of Quizapu. The Soncor magma chamber may have been too deep to collapse when it was emptied, explaining why no significant caldera was formed. The Soncor deposit was subsequently affected

neg: Cascade Volcanoes erupted from a single vent. The eruption was so great that most of Mount Mazama collapsed to form a caldera and subsequent smaller eruptions occurred as water began to fill in the caldera to form Crater Lake. Volcanic ash from the eruption was carried across most of the Pacific Northwest as well as parts of southern Canada. About 13,000 years ago, Glacier Peak generated an unusually strong sequence of eruptions depositing volcanic ash as far away as Wyoming. Most of the Silverthrone Caldera's eruptions in the Pacific Range occurred during the last ice age and was episodically active during both

neg: Grand Canyon of the Yellowstone falls that is called "Uncle Tom's Trail." "Uncle Tom's Trail" is approximately a 3-mile hike. The specifics of the geology of the canyon are not well understood, except that it is an erosional feature rather than the result of glaciation. After the Yellowstone Caldera eruption of about 600,000 years ago, the area was covered by a series of lava flows. The area was also faulted by the doming action of the caldera before the eruption. The site of the present canyon, as well as any previous canyons, was probably the result of this uplift and related faulting, which allowed erosion

neg: Geology of the Bryce Canyon area to be later removed by erosion. Most of the activity at the Marysvale volcanic field occurred during three separate intervals; ~34–22 mya, 22–14 mya and 9–5 mya. Dacites and andesites were erupted above an evolving batholith in the first interval. Crystal-rich ash from the 27-million-year-old (myo) Three Creeks caldera, 24 myo Big John caldera and 23 myo Monroe Peak caldera hardened into tuff. The second and third intervals saw eruptions of great quantities of rhyolites. Alkali-rich rhyolite erupted in the second interval from the 19 myo Mount Belknap caldera. The Marysvale volcanic field collapsed under its own weight around 20

neg: San Salvador of the landscape: southward by the "Cordillera del Balsamo" (Balsam Mountain Range); westward by the Boquerón Volcano and "Cerro El Picacho", the highest point in the municipality at . El Boquerón Volcano was dormant since its last eruption in 1917, but has been active recently. East of the municipality lies the San Jacinto Hill and the caldera of Lake Ilopango, the largest natural body of water in the country with an area of . The caldera is seismically active, but has not erupted since 1880. San Salvador has a tropical wet and dry climate under the Köppen climate classification, and

neg: Teide the Las Cañadas volcano after large-volume explosive eruptions. The second theory is that the caldera was formed by a series of lateral gravitational collapses similar to those described in Hawaii. Evidence for the latter theory has been found in both onshore observations and marine geology studies. From around 160,000 years ago until the present day, the stratovolcanoes of Teide and Pico Viejo formed within the Las Cañadas caldera. Teide last erupted in 1909 from the El Chinyero vent, on the Santiago Ridge. Historical volcanic activity on the island is associated with vents on the Santiago or northwest rift (Boca Cangrejo

neg: Chato Aislado are of dacitic composition, rich in crystals and pumice and display no welding. A lava dome within the caldera reaches a height of , it shows traces of a collapse on its eastern flank. Chato Aislado is of Pleistocene age. The ignimbrite has been dated 1.2 million years ago. The caldera was formed within the ignimbrites erupted early in the volcano's history. The last activity generated the lava dome. Chato Aislado Chato Aislado is a volcano in Chile. Chato Aislado is part of the High Andes of Chile, between 25° and 26°30′ degrees south. The Andes there at altitudes over

neg: Craters of the Moon National Monument and Preserve hunting, not ordinarily permitted in national parks and monuments in the U.S.). Craters of the Moon National Monument and Preserve is co-managed by the National Park Service and the Bureau of Land Management, both under the Department of the Interior. In March 2017, the Idaho Senate voted in favor of petitioning Congress to designate Craters of the Moon a national park. The Snake River Plain is a volcanic province that was created by a series of cataclysmic caldera-forming eruptions which started about 15 million years ago. A migrating hotspot thought to now exist under Yellowstone Caldera in Yellowstone National Park

neg: Geothermal areas of Yellowstone Clark Expedition traveled north of the Yellowstone area in 1806. Local natives that they came upon seldom dared to enter what we now know is the caldera because of frequent loud noises that sounded like thunder and the belief that the spirits that possessed the area did not like human intrusion into their realm. The first white man known to travel into the caldera and see the geothermal features was John Colter, who had left the Lewis and Clark Expedition. He described what he saw as "hot spring brimstone." Beaver trapper Joseph Meek recounted in 1830 that the steam rising

neg: Yellowstone Volcano Observatory Yellowstone Volcano Observatory The Yellowstone Volcano Observatory (YVO) is a volcano observatory that monitors the Yellowstone Caldera in Yellowstone National Park in the United States. The observatory's jurisdiction also includes unmonitored but recently active volcanic centers (mostly Holocene age) in the states of Colorado, Utah, Arizona, and New Mexico. As with other U.S. volcano observatories, it is funded through the United States Geological Survey Volcano Hazards Program. The observatory consists of 8 member agencies: The USGS, the University of Utah, the University of Wyoming, Yellowstone National Park, the Montana Bureau of Mines and Geology, the Wyoming State Geological Survey, the

neg: Megafault Gulf of Mexico. When the fault crosses with the canyon, they fire the satellite at the canyon but plan goes wrong. Instead of heading south, the fault travels north, towards the Yellowstone Caldera. They realize that if the fault crosses the caldera it will explode, expelling several thousand tons of ash into the atmosphere, killing millions and causing a Volcanic winter. They decide to set explosives to block the fault's path. Later, when it reaches the park, Boomer detonates the explosives, causing the fault to stop just short of the volcano, but costing Boomer his life. In the end, an

neg: Lake Corcoran It also influenced sedimentation off the coast of California. The lake existed between about 758,000 and 665,000 years ago. Clay deposition rates indicate that the lake lasted for 50,000 to 100,000 years. The Lava Creek Tuff of Yellowstone Caldera and the Bishop Tuff of the Long Valley Caldera were deposited in the Corcoran Clay. Before Lake Corcoran formed, the Central Valley was a bay open to the south via a passage, until 2 million years ago when the bay was separated from the ocean, probably due to northwestward movement of the Coast Ranges along the San Andreas Fault. Subsequently, the

neg: Salar Grande (caldera) partly filled the caldera, whose scarp reaches an elevation of . The formation of the caldera was influenced by the neighbouring Pedernales-Arizaro fault. The caldera is the source of the Salar Grande ignimbrite, as well as the San Andrés ignimbrite that overlies the former. The ignimbrites erupted by Salar Grande crop out mainly east of the caldera. They are yellow, white and gray and embedded within Miocene basaltic andesite, andesite and dacite lavas. Ages range from 12.07 ± 0.6 - 9.8 ± 0.8 million years ago. Salar Grande (caldera) Salar Grande is a caldera in Chile. The region originally contained

neg: Yellowstone Caldera an explosion 13,800 years ago left a diameter crater at Mary Bay on the edge of Yellowstone Lake (located in the center of the caldera). 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. The volcanic eruptions, as well as the continuing geothermal activity, are a result of a great cove of magma located below the caldera's surface. The magma in this cove contains gases that are kept dissolved by the immense pressure under which the magma is contained.

neg: Long Valley Caldera creek was closed to swimming in 2006 after geothermal activity in the area increased. There are a number of other hot springs in the area, some of which are open to bathers. The tectonic causes of the Long Valley volcanism are still largely unexplained and are therefore a matter of much ongoing research. Long Valley is not above a hotspot as is Yellowstone or Hawaii, nor is it the result of subduction such as that which produces the volcanism of the Cascades. The known volcanic history of the Long Valley Caldera area started a few million years ago when magma

neg: Galán over half of its volume. The volume of the individual ignimbrites increases the younger they are with the initial Blanco and Merihuaca ignimbrites having a volume of about . The last eruption may have generated a caldera that was later obliterated. Emission of lava flows occurred during the Toconquis phase as well, in general there was vigorous volcanic activity between the eruptions that formed the main ignimbrites. The Cueva Negra ignimbrite was emplaced after the Toconquis Group, and small lava domes and pyroclastic flows continued to be erupted until the Galán ignimbrite proper. The magmatic system shallowed during this time,

neg: Yellowstone hotspot Yellowstone Plateau volcanic field joins the ranks of its deceased ancestors in the Snake River Plain. (References to be added: Kathryn Watts (Nov 2007) GeoTimes "Yellowstone and Heise: Supervolcanoes that Lighten Up": Kathryn E. Watts, Ilya N. Bindeman and Axel K. Schmitt (2011) Petrology, Vol. 52, No. 5, "Large-volume Rhyolite Genesis in Caldera Complexes of the Snake River Plain: Insights from the Kilgore Tuff of the Heise Volcanic Field, Idaho, with Comparison to Yellowstone and Bruneau-Jarbidge Rhyolites" pp. 857–890). Yellowstone hotspot The Yellowstone hotspot is a volcanic hotspot in the United States responsible for large scale volcanism in Idaho, Montana,

neg: Sairecabur partial melting of the mantle involving peridotite and subsequent interaction with the crust and fractional crystallization. Andesites erupted before the caldera formation formed at temperatures higher than dacites erupted after the formation of the caldera. , and isotope ratios are typical for magmas in CVZ. The isotope ratios are consistent with these found in the crust, specifically of the so-called "Antofalla" domain of Andean crust, the remnant of a terrane of Gondwana. The 7 million years old Chaxas ignimbrite massif has been related to the caldera-forming eruption at Sairecabur. These dacitic ignimbrites spread southwest towards the Salar de Atacama. Such

neg: 2010 eruptions of Eyjafjallajökull the caldera of a volcano high, which has erupted relatively frequently since the last ice age. The most recent major eruptions occurred in 920, 1612, and from 1821 to 1823. Previous eruptions of Eyjafjallajökull have been followed by eruptions at its larger neighbour, Katla. On 20 April 2010 Icelandic President Ólafur Grímsson said, "the time for Katla to erupt is coming close ... we [Iceland] have prepared ... it is high time for European governments and airline authorities all over the world to start planning for the eventual Katla eruption". The volcanic events starting in March 2010 were considered to

neg: Island Park, Idaho Henry's Fork Caldera is still one of the largest calderas in the world and is the only large caldera in the Yellowstone region that is plainly visible. It has a nearly level wide circular floor that slopes slightly towards the southeast. The caldera floor is at about of elevation with the rim generally being several hundred feet higher. The Henry's Lake Flat area, north of the caldera, is a little higher. Henry's Lake is at with the flats sloping slightly southward towards the caldera. The Island Park area is mostly forested with many meadows and grasslands. It is mostly level

neg: Porco (caldera) semseyite, sphalerite, stannite, and stephanite. The climate is cold and dry, with temperatures below occurring in ten months. Precipitation is low, amounting to about . Twelve million years ago, the Porco Tuff was erupted from the volcano, causing the formation of the Porco caldera. This welded tuff accumulated to thicknesses of more than inside the caldera and extended outside of the caldera, where it crops out in patches outside of its western margin. Material from the pre-caldera basement consisting of Cretaceous sandstone breccia was embedded in the tuff on the southern and eastern side of the caldera. Porco is also

neg: Cerro Panizos located east of the main arc and is supplied chiefly by dacite magmas. Beneath Panizos lie Tertiary ignimbrites and a Paleozoic sedimentary basement. The huge Panizos ignimbrite erupted by Cerro Panizos has a minimum volume of . It erupted during an event 6.71 ± 0.04 mya and was preceded by another ignimbrite 7.9 mya ago. The last activity is a lava flow 6.1 mya ago. The caldera is hidden beneath a shield with a diameter of and some of its central summits are over high. It has been referred to as an "ignimbrite shield". The centre is located on the