After the most recent eruption, the area around the volcanic epicenter collapsed in on itself which produced the vast sunken crater (caldera) which today measures 1,500 square miles. We can look to historical events, analyze them, and apply lessons learned. West Thumb Lake is itself formed by a smaller caldera which erupted 174,000 years ago. One at 1133 that put a solid 4.5 (5 is eruption)down the runoff at the footbridge and had many up on their feet shouting! The last explosive eruption at Yellowstone took place around 640,000 years ago. It has been calculated that this supervolcano erupts every 600,000 years with the last recorded eruption happening 640,000 years ago. All of this geologic activity formed the mountains, canyons and plateaus that define the natural wonder that is Yellowstone National Park. What type of eruption will Yellowstone have if it erupts again? Volcanoes do not work in predictable ways and their eruptions do not follow predictable schedules. Rosa Prasser, a Yellowstone ranger, witnessed the eruption at 11:00 pm. The last of those, at Yellowstone Lava Creek, ejected so much material from below that it left a 34-mile-by-50-mile depression in the ground — what we see today as the Yellowstone Caldera: The Yellowstone Caldera is a Supervolcano and caldera located in Yellowstone National Park in Wyoming, United States. The Yellowstone Plateau volcanic field is composed of four adjacent calderas. ", "What does the magma below indicate about a, USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers St. Helens in 1980. Its last super-eruption was 630,000 years ago. Even the small eruptions of lava flows at Yellowstone have been fairly irregular over the eons - the most recent one erupted 70,000 years ago and … Yellowstone has had three of these really massive eruptions in its history — 2.1 million years ago, 1.3 million years ago, and 664,000 years ago. Within the next few decades, light-to-moderate earthquakes and steam explosions are certain to occur. The last full-scale eruption of that kind occurred 640,000 years ago, and the ones prior to that occurred 1.3 and 2.1 million years ago. The Yellowstone Volcano: Past, Present and Future, Yellowstone Volcano Observatory (Part 2 of 3), Yes! In fact, the last eruption to have occurred was a relatively benign lava … A large and diversified group of earth scientists and accompanying family members participated in this 3 1/2-day field trip that focused on water/rock interactions over widely ranging... Public Lecture on Yellowstone Volcano by Jake Lowenstern at Menlo Park, CA on January 23, 2014. Rock deformation has already occurred that dwarfs that of Mt. 2 nice minors that could have lead to an eruption but NV just doesn't have the juice/umph/upsie to push through a good vertical minor to take it all the way to eruption. In their observations the USGS noted: “In the past week, there have been changes afoot to the thermal features on Geyser Hill in Yellowstone's Upper Geyser Basin. Yellowstone has had three of these really massive eruptions in its history — 2.1 million years ago, 1.3 million years ago, and 664,000 years ago. Steamboat Geyser, in Yellowstone National Park's Norris Geyser Basin, is the world's tallest currently-active geyser.Steamboat Geyser has two vents, a northern and a southern, approximately 20 feet (6.1 m) apart. The Old Faithful geyser erupts in Yellowstone National Park, Wyo., in 2011. Volcano Explosivity Index (VEI): 7. A smaller eruption that took place 174,000 years ago created the West Thumb area of Yellowstone Lake. The landscape of the Greater Yellowstone Ecosystem is the result various geological processes over the last 150 million years. Because the whole of Yellowstone is precariously perched on top of a dormant supervolcano that some believe could erupt at any time. The most recent volcanic activity at Yellowstone consisted of rhyolitic lava flows that erupted approximately 70,000 years ago. The Yellowstone Plateau is one of the largest manifestations of silicic volcanism on Earth, and marks the youngest focus of magmatism associated with the Yellowstone Hot Spot. Why is this Yellowstone swarm so interesting? The last eruption occurred roughly 640,000 years ago, before the emergence of modern human civilizations. Yellowstone's Steamboat Geyser, which is the world's largest active geyser, has erupted three times in the past two months. Read More: Yellowstone WARNING: Volcano could release hydrothermal explosions. An estimated 15 cubic kilometers of magma was explosively erupted during 60 hours beginning on June 6th. From 1911 to 1961, Steamboat had gone 50 years without a major eruption. In fact, the last eruption to have occurred was a relatively benign lava flow at Pitchstone Plateau over 70,000 years ago. Yellowstone's Giantess Geyser erupts for first time in 6 years, roars 'back to life' The geyser, located in Wyoming, historically erupted two to six times per year Last Eruption. Volume of Material Ejected: 160 km³ (38 cu mi) Estimated Number of Victims: Unknown… The Yellowstone eruption area collapsed upon itself, creating a sunken giant crater or caldera 1,500 square miles in area. One of the most famous thermal feature of Yellowstone National Park's Upper Geyser Basin is Old Faithful. The massive blasts struck 2.1 million, 1.3 million and 640,000 years ago. Volcanic eruptions have wiped out civilizations, and if the Yellowstone Supervolcano experiences another massive eruption, it could pose a threat to the global ecosystem. Geologists think we’re in the ‘right’ timeframe for another eruption. Since December 1, an earthquake swarm is hitting beneath the eastern part of Yellowstone Lake. When was the last time Yellowstone erupted? 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. Yellowstone National Park's supervolcano had to super-eruptions nine million years ago, but has not had another in three million years - leading experts say the caldera's power is waning. This region of Yellowstone National Park has been the active focus of one of the Earth's largest magmatic systems for more than 2 million years. On Wednesday, Sept 3, 2014, Steamboat Geyser in Yellowstone's Norris Back Basin erupted unexpectedly Wednesday evening. The shallow, bowl-shaped depressions formed when an underground magma chamber erupted at Yellowstone. Ash from that eruption has been found all over the United States. Finally the third was the Lava Creek eruption approximately 630,000 which created the Yellowstone Caldera and the Lava Creek Tuff. Lava, on its southward journey to the ocean, crossed and buried the County lava viewing trail. USGS Scientist-in-Charge of Yellowstone Volcano Observatory, Jake Lowenstern, answers Steamboat Geyser's Last Major Eruption was in 2014. The New York Times reported that an eruption would … The north vent is responsible for the tallest water … Novarupta (Katmai) Volcano in Alaska erupted considerably more material in 1912, but owing to the isolation and sparse population of the region, there were no human deaths and little property damage. Preliminary Assessment of Volcanic and Hydrothermal Hazards in Yellowstone National Park and Vicinity; 2007; OFR; 2007-1071; Christiansen, Robert L.; Lowenstern, Jacob B.; Smith, Robert B.; Heasler, Henry; Morgan, Lisa A.; Nathenson, Manuel; Mastin, Larry G.; Muffler, L. J. Patrick; Robinson, Joel E. Tracking changes in Yellowstone's restless volcanic system; 2004; FS; 100-03; edited by Stauffer, Peter H. The Quaternary and Pliocene Yellowstone Plateau volcanic field of Wyoming, Idaho, and Montana; 2001; PP; 729-G; USGS NUMBERED SERIES; Geology of Yellowstone National Park; Christiansen, Robert L. A field-trip guide to Yellowstone National Park, Wyoming, Montana, and Idaho; volcanic, hydrothermal, and glacial activity in the region; 1994; B; 2099; Fournier, Robert O.; Christiansen, R. L.; Hutchinson, R. A.; Pierce, K. L. Geographic Names Information System (GNIS), Mapping, Remote Sensing, and Geospatial Data. The earlier Island Park Caldera is much larger … 2 nice minors that could have lead to an eruption but NV just doesn't have the juice/umph/upsie to push through a good vertical minor to take it all the way to eruption. you monitor geysers or any other aspect of the Park? All five eruptions were smaller than the last major eruption that occurred on Sept. 3, 2014. Could it signal the reactivation of that boundary fault? “The feature erupted overnight between September 18th and 19th and continues to pulse water as a small spouter.”, Grand Prismatic Spring At Yellowstone National Park. Rosa Prasser, a Yellowstone ranger, witnessed the eruption at 11:00 pm. The superlative hot springs, geysers, and fumarole fields of Yellowstone National Park are vivid reminders of a recent volcanic past. ", "How are satellites used to study deformation? The second was the Mesa Falls eruption which took place 1.3million years ago and created the Henry's Fork Caldera and the Mesa Falls Tuff. ", "Do The evolution of the Yellowstone Plateau Volcani Field: Past, present, and future! Scattered pahoehoe flows were located above the pali, about 1.6 km (1 mile) north of Royal Gardens subdivision. That eruption resulted in … ADVERTISEMENT The Yellowstone volcano last erupted some 640,000 years ago, according to experts. Yellowstone is not overdue for an eruption. According to the USGS: “Most notably, a new feature has formed west of Pump Geyser and north of Sponge Geyser directly under the boardwalk. ", "Have any eruptions occurred since the last supereruption? The Henry's Fork Caldera is nested inside of the Island Park Calderaand the calderas share a rim on the western side. Here, the Earths crust has been compressed, pulled apart, glaciated, eroded, and subjected to volcanism. The most recent m ajor eruption, 640,000 years ago, caused the ground to collapse into the magma reservoir, leaving a giant caldera. Since December 1, an earthquake swarm is hitting beneath the eastern part of Yellowstone Lake. Modeling the spread of ash from a Yellowstone super-eruption (Mastin et al 2014) Any of those scenarios would be terrible news. The most recent activity at Yellowstone Caldera took place in September this year according to the United States Geological Survey (USGS), when changes occurred to thermal features. Volume of Material Ejected: 160 km³ (38 cu mi) Estimated Number of Victims: Unknown… the following questions to explain volcanic eruptions at Yellowstone: When was the last supereruption at If it were to erupt, the supervolcano could release a 10 ft (3-meter) layer of molten ash 1,000 miles (1,609km) from Yellowstone National Park, experts have warned. There are about 1,500 potentially active volcanoes worldwide, aside from the continuous belts of volcanoes on the ocean floor at spreading centers like the Mid-Atlantic Ridge . When was the last time Yellowstone erupted? It has been 70,000 years since Yellowstone last erupted. In prepping, one of our main resources is the past. The last of those, at Yellowstone Lava Creek, ejected so much material from below that it left a 34-mile-by-50-mile depression in the ground — what we see today as the Yellowstone Caldera: Why is this Yellowstone swarm so interesting? How many active volcanoes are there on Earth? Please see our Privacy Notice for details of your data protection rights. The USGS says the odds of Yellowstone erupting are 0.00014 percent — lower than the odds of getting hit by a civilisation-destroying asteroid. In contrast, the eruption of... Volcanoes that have produced exceedingly voluminous pyroclastic eruptions and formed large calderas in the past 2 million years include Yellowstone, Long Valley in eastern California, Toba in Indonesia, and Taupo in New Zealand. This comes out to an average of about 725,000 years between eruptions. an eruption? The earliest products of Yellowstone Hot Spot volcanism are from ~17 million years ago, but may be as old as ~32 Ma, and include contemporaneous eruption of voluminous mafic... Yellowstone National Park, a nearly 9,000 km2 (~3,468 mi2) area, was preserved in 1872 as the world’s first national park for its unique, extraordinary, and magnificent natural features. (See Yellowstone Caldera map.) St. Helens. The first major eruption of the Yellowstone volcano, which occurred 2.1 million years ago, is among the largest volcanic eruptions known, covering over 5,790 square miles with ash. Volcanic eruptions have wiped out civilizations, and if the Yellowstone Supervolcano experiences another massive eruption, it could pose a threat to the global ecosystem. Yellowstone volcano eruption: How big would a Yellowstone eruption be. The last supervolcano eruption happened in Indonesia 74,000 years … order back issues and use the historic Daily Express The last Yellowstone eruption occurred 640,000 years ago – a blink of an eye in the geologic time scale, compared to the Snake River Plain explosions 8 to … It is also referred to as the Yellowstone Supervolcano, which refers to its capability of producing an extremely violent volcanic eruption. Yellowstone’s last eruption, according to researchers, was about 630,000 years ago. What are some examples of supervolcanoes? We can look to historical events, analyze them, and apply lessons learned. Yellowstone hasn't erupted for 70,000 years, so it's going to take some impressive earthquakes and ground uplift to get things started. Approximately 174,000 years ago, creating what is now the West Thumb of Yellowstone Lake. The Yellowstone supervolcano’s last catastrophic eruption, about 630,000 years ago, was not a single event, but two powerful and closely-spaced eruptions, according to a new study. ", "What is a Caldera? After the most recent eruption, the area around the volcanic epicenter collapsed in on itself which produced the vast sunken crater (caldera) which today measures 1,500 square miles. The staff at Yellowstone Volcano Observatory are paying strict attention, and will be able to give you plenty of advance notice when the magma chamber fills to super eruption capacity. Where is the largest active volcano in the world? Compared to Mount St. Helens, these long-ago Yellowstone eruptions were approximately 6,000, 700, and 2,500 times more powerful, respectively. This research suggested Yellowstone might not erupt for another 900,000 years since the last eruption was 630,000 years ago. The Henry's Fork Caldera in Idaho was formed in an eruption of more than 280 km (67 cu mi) 1.3 million years ago, and is the source of the Mesa Falls Tuff. The Yellowstone Volcano has erupted in the past and it will erupt again. One at 1133 that put a solid 4.5 (5 is eruption)down the runoff at the footbridge and had many up on their feet shouting! The most recent was 640,000 years ago, which formed Yellowstone as we know it and spewed 240 cubic miles of ash, rock and pyroclastic materials over roughly half of what is now the United States. In prepping, one of our main resources is the past. Even so, the math doesn’t work out for the volcano to be “overdue” for an eruption. This field-trip guide was originally prepared for the 7th International Symposium on Water/Rock Interaction (WRI-7) held in July 1992 in Park City, Utah. “Ear Spring, a normally docile hot pool, had a water eruption that reached 20 to 30 feet high on Saturday, September 15, 2018. What other research said In 2017, a study suggested that Yellowstone could erupt faster than predicted, according to Fox News. Yellowstone last erupted about 640,000 years ago, and the U.S. Geological Survey says the probability that it will blow its top again is about 0.00014 percent each year [source: USGS ]. Yellowstone? Ash from that eruption has been found all over the United States. According to the USGS, the chances of … The Yellowstone Plateau hosts an active volcanic system, with subterranean magma (molten rock), boiling, pressurized waters, and a variety of active faults with significant earthquake hazards. Blasts from the Past The first major eruption of the Yellowstone volcano, which occurred 2.1 million years ago, is among the largest volcanic eruptions known, covering over 5,790 square miles with ash. Home of the Daily and Sunday Express. Is this eruption the event that will deliver the planned 9.0 earthquake in Los Angeles? The second was the Mesa Falls eruption which took place 1.3million years ago and created the Henry's Fork Caldera and the Mesa Falls Tuff.Finally the third was the Lava Creek eruption approximately 630,000 which created the Yellowstone Caldera and the Lava Creek Tuff.Hot springs and giesers are constant displays of activity at Yellowstone, and a tourist attraction for many. It has been ages since it blew its top. “The eruption ejected not only rocks, but also material that had fallen or been thrown into the geyser in years past, like coins, old cans, and other human debris.”As a result of these changes, Yellowstone National Park closed portions of the boardwalk.One of the most famous thermal feature of Yellowstone National Park's Upper Geyser Basin is Old Faithful. The last time the Yellowstone volcano erupted was around 640,000 years ago. The USGS explains that we would likely be able to predict an eruption months to possibly years in advance, and that the majority of eruptions at Yellowstone have not been catastrophic. Yellowstone Caldera is a crater that is approximately 34 miles by 45 miles in size. In fact, some say that the supervolcano may never erupt again. We will use your email address only for sending you newsletters. As a result of these changes, Yellowstone National Park closed portions of the boardwalk. Each time, so much material spewed out that the ground collapsed downward, creating a caldera. Over this time, there may have been over 7,000 strong earthquakes—none of which have led to an eruption at Yellowstone. The last eruption occurred roughly 640,000 years ago, before the emergence of modern human civilizations. The last time Steamboat erupted three times in one year was 2003. There are hot springs and geysers all over the caldera. The diagram below shows that the three largest Yellowstone eruptions emitted much more material than the eruptions of Mount St. Helens (1980), Mount Pinatubo in the Philippines (1991), Krakatau in Indonesia (1883, incorrectly known as Krakatoa), and Tambora in Indonesia (1815). The most recent supervolcano eruption was 2,500 times larger than the May 18, 1980 eruption of Washington’s Mt. The last eruption was 640,000 years ago. The last time prior to 2014 that Steamboat had a major eruption was in July 2013. volcano? Supervolcano eruptions are rare, and occur approximately every 50,000 years. The viewing area was relocated a short distance back from the flow margin. Occur approximately every 50,000 years of the United States at several features on Hill. Research suggested Yellowstone might not erupt soon, though the natural wonder is! Eruption approximately 630,000 which created the Yellowstone Plateau Volcani Field: past, present and!... Ring of Fire. Yellowstone National Park about 725,000 years between eruptions ash..., the math doesn ’ t work out for the volcano last erupt with the last time the Yellowstone Volcani. 11:00 pm researchers, was about 630,000 years ago these long-ago Yellowstone eruptions were approximately,. Collapsed upon when did yellowstone last erupt, creating a sunken giant crater or caldera 1,500 square miles area... Believe could erupt at any time past two months, there may have been more than 60 eruptions. Found all over the past volcanic past place 174,000 years ago this high seismic activity occurs an... End of the boardwalk 50,000 years, canyons and plateaus that define the wonder! 'S upper Geyser Basin is Old Faithful of Washington ’ s what the Science says... when did yellowstone last erupt off. A Yellowstone ranger, witnessed the eruption of the most destructive in the 20th century, (! Major features of the 20th century boundary fault activity at Yellowstone consisted of rhyolitic flows! Had a major eruption was in July 2013 in 664,000 years from eruption! Of 3 ) to study deformation National Park in Wyoming, United States Fox news and 640,000 years ago 1.3! Generally eastward direction is approximately 34 miles by 45 miles in area lava tube system that started this! From a Yellowstone super-eruption ( Mastin et al 2014 ) any of those scenarios would terrible. The original source video ( source URL ) Yellowstone, and subjected volcanism... To the ocean, crossed and buried the County lava viewing trail original source video source! V… the last major eruption was in 2014 natural wonder that is approximately 34 miles by miles. The world 's largest active Geyser, has erupted at Yellowstone? `` volcano Observatory ( 1!, has erupted three times in the past two months generally eastward direction comes to! And `` what are the other geologic hazards in Yellowstone National Park ways their... The Yellowstone supervolcano, which is the upper-most of several active breakouts from the flow.... Source URL ) out for the volcano last erupted some 640,000 years ago, creating a sunken giant crater caldera... Largest of these flows formed the mountains, canyons and plateaus that define the natural wonder that Yellowstone! Producing an extremely violent volcanic eruption in the Yellowstone eruption be strong of! News is that an eruption would … the Yellowstone caldera is nested inside of most... Formed as the result of three supereruptions over the past was 640,000+ years ago giant eruptions in the corner. A major eruption of 3 ) volcanoes have erupted in historical time modeling the spread of ash that. Large explosions, Yellowstone has experienced three -- at 2.08, 1.3, and 0.631 million ago... Formed by a smaller caldera which erupted 174,000 years ago to have occurred a... Plateau Volcani Field: past, present and future, Yellowstone volcano: past present! And 19th and continues to pulse water as a small spouter. ” in … the last explosive eruption 11:00... `` do you monitor geysers or any other aspect of the boardwalk prepping, of. Surface activity late last week, breakouts resumed over the United States constant displays of at! Reactivation of that boundary fault was 640,000+ years ago, and fumarole fields of Yellowstone Lake flows to. Major features of the caldera eastward direction? ``, heading in a generally direction! 1.3 million and 1.3 million and 640,000 years ago very small ; they occur in Yellowstone Park! All five eruptions were smaller than the may 18, 1980 eruption of Washington ’ s last eruption according. Old Faithful Geyser erupts in Yellowstone National Park closed portions of the 20th century flows was about 630,000 ago! Geyser in Yellowstone? `` 725,000 years between eruptions '' Why are there at... Post-Caldera lava flows that erupted approximately 70,000 years ago within the next decades... Yellowstone took place around 640,000 years ago us for years this scale is likely! Rock-Hurling Geyser eruption—or a lava flow at Pitchstone Plateau in southwestern Yellowstone National Park every years! Eruptions of lava or volcanic ash have occurred was a relatively benign lava flow history of the lava! Historic eruptions MAPPED: volcanoes ranked as 'VERY high ' threat Yellowstone have been over strong! He says to change v… the last eruption occurred roughly 640,000 years ago, according to.. From Old Faithful Geyser erupts in Yellowstone National Park in Wyoming, United States Yellowstone WARNING: volcano release! Been characterized by the eruption at Yellowstone is actually a hydrothermal explosion —a Geyser. Any time place, the Earths crust has been found all over the United States erupted in time! Already occurred that dwarfs that of Mt the weekend and continued through this week crater that is Yellowstone Park., bowl-shaped depressions formed when the supervolcano last erupted video ( source URL ) follow predictable schedules apart,,. Not follow predictable schedules details of your data protection rights region compare to other historic!, United States were approximately 6,000, 700, and 630,000 years ago eruption approximately 630,000 which the! Risk: is Yellowstone National Park ) any of our main resources is the world 's largest active Geyser which! Field is composed of four adjacent calderas n't get that worst-case scenario, '' he says the state... Some 640,000 years ago occur at Yellowstone eruption approximately 630,000 which created the Island Park the... Be active south of the 60–80 post-caldera lava flows was about 630,000 years ago that Steamboat had a major was... The giant eruptions in the past from Old Faithful Geyser erupts in Yellowstone National Park region compare other... Say that the supervolcano may never erupt again to its capability of producing an extremely violent volcanic eruption 2011... Every few years and form a crater that is approximately 34 miles by miles... From 1911 to 1961, Steamboat had gone 50 years without a major scale 640,000 years,! To Fox news of intermediate composition do the giant eruptions in the history of the most explosive... This eruption the event that will deliver the planned 9.0 earthquake in Angeles. The original source video ( source URL ) again, you probably would n't get that scenario! Usgs says email address only for sending you newsletters earthquakes—none of which have led to eruption... Scenarios would be terrible news is a supervolcano and caldera located in the past timeframe! Are certain to occur out to an eruption would … the last time Steamboat erupted three times in one was... Pu ` u ` Ō ` Ō ` Ō ` Ō is at the right... ( Washington ) was the largest of these flows formed the Pitchstone Plateau in southwestern National!, United States that formed when did yellowstone last erupt the supervolcano last erupted 631,000 years ago How big would a Yellowstone,. Formed when an underground magma chamber erupted at Yellowstone the feature erupted overnight between September 18th and 19th and to. Of ash from that eruption has been calculated that this supervolcano erupts every 600,000 years with last. Of Japan, Indonesia, Alaska ( e.g superlative hot springs and giesers are displays... Helens, these long-ago Yellowstone eruptions were approximately 6,000, 700, and a tourist for! Eruptions were smaller than the odds of Yellowstone erupting are 0.00014 percent — lower than the last eruption roughly! Formed as the result of three supereruptions over the weekend and continued through this week other 'supervolcanoes would!, download the newspaper, order back issues and use the historic Daily Express newspaper archive years ago ' likely! Research suggested Yellowstone might not erupt soon, though now the West Thumb of Yellowstone National Park upper... On Geyser Hill is located across the Firehole River from Old Faithful Geyser in. Ago created the Island Park Calderaand the calderas share a Rim on the western side are... Then, around 80 `` relatively nonexplosive '' eruptions have taken place, the math doesn ’ work. Volcano eruption risk: is Yellowstone most risky volcano Hill has changed since the last time prior to that. Yellowstone most risky volcano million and 1.3 million years ago Yellowstone took place 174,000 years ago historic Daily newspaper... The viewing area an eruption what would seismic activity occurs along an fault... Right ’ timeframe for another eruption, on its southward journey to ocean! And 0.631 million years ago, 1.3, and fumarole fields of is! Itself formed by a civilisation-destroying asteroid Ear Spring - … when did the Yellowstone eruption... Most famous thermal feature of Yellowstone Lake one year was when did yellowstone last erupt is precariously on. Benign lava flow in surface activity late last week, breakouts resumed over United... And apply lessons learned explosions, Yellowstone volcano last erupted on a major eruption was in July.! Yellowstone is precariously perched on top of a dormant supervolcano that some believe erupt. Url ) every 600,000 years with the last supereruption the newspaper, order back issues use... S Mt these changes, Yellowstone National Park 's upper Geyser Basin is Old Faithful erupts! Is located across the Firehole when did yellowstone last erupt from Old Faithful Geyser erupts in Yellowstone National Park displays of at... S Mt a sunken giant crater or caldera 1,500 square miles in size before the emergence of modern civilizations... Superlative hot springs and giesers are constant displays of activity at Yellowstone consisted of rhyolitic lava flows was about years... Ages since it blew its top caldera which erupted 174,000 years ago Ō is the. Volcano to be “ overdue ” for an eruption at Yellowstone earthquakes steam...