uellowstone caldera





Dee Finney's blog

start date July 20, 2011

Today's date March 114, 2012

page 170








YOU CAN FIND MY OTHER YELLOWSTONE PAGE AT  http://www.earthmountainview.com/yellowstone/yellowstonen.htm

and my other pages about YEllowstone at:  http://search.yahoo.com/search;_ylt=A0oGdXcgLGFPJiYA4Nul87UF?p=site%3Aearthmountainview.com%20%20yellowstone&fr=slv8-att&fr2=sfp


This isi all new information since those other pages were done:



The Old Yellowstone Highway was replaced by modern U.S. 20 between Casper and Thermopolis. The "Park to Park" was part of the "Yellowstone Highway," which ran Denver, Casper, Thermopolis, East Entrance Yellowstone Park. The "Yellowstone Highway" was established first but was absorbed by the "Park to Park," which initially ran an extension from the "Yellowstone Highway" in Denver to Mesa Verde, Co. The "Park to Park" soon connected all major western national parks and in doing so, the "Yellowstone Highway" lost prominence but not its name, which still described the Denver-Yellowstone route. This routing information was researched by Mike Jamison from Lee Whiteley's recommended new book The Yellowstone Highway, Denver to the Park, Past and Present.

There was much debate in the mid-1920s regarding the future routing of U.S. 20. Plans originally called for U.S. 20 to run from Astoria, Oregon, to Yellowstone National Park, Wyoming, via U.S. 30. This routing was in the 1926 Rand McNally Road Atlas. At that time, U.S. 30 was planned to end in Salt Lake City, Utah. However, Oregon and Idaho balked at the plan. For more on this, please turn to the U.S. 30 page.

When the confusion cleared up, U.S. 30 was routed to Astoria, while U.S. 20 was truncated. U.S. 20 ended (or began) at Yellowstone National Park's East Entrance. Heading east, U.S. 20 went all the way to Boston, Massachusetts. Two auxiliary U.S. Routes from U.S. 20 -- U.S. 320 and U.S. 420 -- connected U.S. 20 to Riverton and Billings.

U.S. 20 was extended west into Montana, Idaho, and Oregon around 1942, partially to replace old U.S. 28 in Oregon. Despite this extension, there are two sections of U.S. 20 with an "official gap" through the Park, according to AASHTO. Hence, U.S. 20 is not "officially" a transcontinental U.S. route, but for all intents and purposes it is ... at least in the summer.







The Yellowstone Caldera is the volcanic caldera located in Yellowstone National Park in the United States, sometimes referred to as the Yellowstone Supervolcano. The caldera is located in the northwest corner of Wyoming, in which the vast majority of the park is contained. The major features of the caldera measure about 34 by 45 miles (55 by 72 km).[3]

Yellowstone lies over a hotspot where light, hot, molten mantle rock rises towards the surface. While the Yellowstone hotspot is now under the Yellowstone Plateau, it previously helped create the eastern Snake River Plain (to the west of Yellowstone) through a series of huge volcanic eruptions. Although the hotspot's apparent motion is to the east-northeast, the North American Plate is really moving west-southwest over the stationary hotspot in the Earth's mantle.[4]

Over the past 18 million years or so, this hotspot has generated a succession of violent eruptions and less violent floods of basaltic lava. Together these eruptions have helped create the eastern part of the Snake River Plain from a once-mountainous region. At least a dozen of these eruptions were so massive that they are classified as supereruptions. Volcanic eruptions sometimes empty their stores of magma so swiftly that they cause the overlying land to collapse into the emptied magma chamber, forming a geographic depression called a caldera. Calderas formed from explosive supereruptions can be as wide and deep as mid- to large-sized lakes and can be responsible for destroying broad swaths of mountain ranges.

The oldest identified caldera remnant straddles the border near McDermitt, Nevada-Oregon, although there are volcaniclastic piles and arcuate faults that define caldera complexes more than 60 km (37 mi) in diameter in the Carmacks Group of southwest-central Yukon, Canada, which is interpreted to have formed 70 million years ago by the Yellowstone hotspot.[5][6] 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 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 (30.48 cm) 1,000 miles (1,600 km) away in northeastern Nebraska and killed large herds of rhinoceros, camel, and other animals at Ashfall Fossil Beds State Historical Park. Within the past 17 million years, 142 or more caldera-forming eruptions have occurred from the Yellowstone hotspot.[7]

The loosely defined term 'supervolcano' has been used to describe volcanic fields that produce exceptionally large volcanic eruptions. Thus defined, the Yellowstone Supervolcano is the volcanic field which produced the latest three supereruptions from the Yellowstone hotspot. The three super eruptions occurred 2.1 million, 1.3 million, and 640,000 years ago, forming the Island Park Caldera, the Henry's Fork Caldera, and Yellowstone calderas, respectively.[8] The Island Park Caldera supereruption (2.1 million years ago), which produced the Huckleberry Ridge Tuff, was the largest and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption. The next biggest supereruption formed the Yellowstone Caldera (640,000 years ago) and produced the Lava Creek Tuff. The Henry's Fork Caldera (1.2 million years ago) produced the smaller Mesa Falls Tuff but is the only caldera from the Snake River Plain-Yellowstone (SRP-Y) hotspot that is plainly visible today.[9]

Non-explosive eruptions of lava and less-violent explosive eruptions have occurred in and near the Yellowstone caldera since the last supereruption.[10][11] 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; an explosion 13,800 years ago left a 5 kilometer diameter crater at Mary Bay on the edge of Yellowstone Lake (located in the center of the caldera).[12][13] 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.[14]

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 only by the immense pressure that the magma is under. If the pressure is released to a sufficient degree by some geological shift, then some of the gases bubble out and cause the magma to expand. This can cause a runaway reaction. If the expansion results in further relief of pressure, for example, by blowing crust material off the top of the chamber, the result is a very large gas explosion.


Due to the volcanic and tectonic nature of the region, the Yellowstone Caldera experiences between 1000 and 2000 measurable earthquakes a year. Most are relatively minor, measuring a magnitude of 3 or weaker. Occasionally, numerous earthquakes are detected in a relatively short period of time, an event known as an earthquake swarm. In 1985, more than 3000 earthquakes were measured over several months. More than 70 smaller swarms have been detected between 1983 and 2008. The USGS states that these swarms could be caused more by slips on pre-existing faults than by movements of magma or hydrothermal fluids.[16][17]

In December 2008, continuing into January 2009, more than 500 quakes were detected under the northwest end of Yellowstone Lake over a seven day span, with the largest registering a magnitude of 3.9.[18][19] The most recent swarm started in January 2010 after the Haiti earthquake and before the Chile earthquake. With 1620 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 on January 21, 2010 at 11:16 PM MST.[17][20] This swarm reached the background levels by 21 February.[edit] Volcanic hazardsThe last full-scale eruption of the Yellowstone Supervolcano, the Lava Creek eruption which happened nearly 640,000 years ago,[21] ejected approximately 240 cubic miles (1,000 km3) of rock, dust and volcanic ash into the sky.[13]

Geologists are closely monitoring the rise and fall of the Yellowstone Plateau, which measures on average 0.6 inches (1.5 cm) yearly, as an indication of changes in magma chamber pressure.[22][23]

The upward movement of the Yellowstone caldera floor between 2004 and 2008 — almost 3 inches (7.6 cm) each year — was more than three times greater than ever observed since such measurements began in 1923.[24] From mid-summer 2004 through mid-summer 2008, the land surface within the caldera moved upwards as much as 8 inches (20 cm) at the White Lake GPS station.[25][26] By the end of 2009, the uplift had slowed significantly and appeared to have stopped.[27] In January 2010, the USGS stated that "uplift of the Yellowstone Caldera has slowed significantly."[28] and uplift continues but at a slower pace.[29] 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."[13]


Hydrothermal explosion hazard

Studies and analysis may indicate that the greater hazard comes from hydrothermal activity which occurs independently of volcanic activity. Over 20 large craters have been produced in the past 14,000 years, resulting in such features as Mary Bay, Turbid Lake, and Indian Pond which was created in an eruption about 1300 BC.

Lisa Morgan, a USGS researcher, explored this threat in a 2003 report, and in a talk postulated that an earthquake may have displaced more than 77 million cubic feet (2,200,000 m3) (576,000,000 US gallons) of water in Yellowstone Lake, creating colossal waves that unsealed a capped geothermal system leading into the hydrothermal explosion that formed Mary Bay.[30][31]

Further research shows that earthquakes from great distances do reach and have effects upon the activities at Yellowstone, such as the 1992 7.3 magnitude Landers earthquake in California’s Mojave Desert that triggered a swarm of quakes from more than 800 miles (1,300 km) away and the Denali fault earthquake 2,000 miles (3,200 km) away in Alaska that altered the activity of many geysers and hot springs for several months afterwards.[32]

The head of the Yellowstone Volcano Observatory, Jake Lowenstern, has proposed major upgrades and extended monitoring since the U.S. Geological Survey classified Yellowstone as a “high-threat” system.[33]

[edit] Yellowstone hotspot origin

Path of the Yellowstone hot spot over the past 15 million years

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.[34][35] Others prefer a deep mantle origin (mantle plume).[36] Part of the controversy is due to the relatively sudden appearance of the hotspot in the geologic record. Additionally, the Columbia Basalt flows appeared at the same approximate time, causing speculation about their origin.[37]


[edit] References

  1. ^ "Mount Sheridan,vbe 3 Wyoming". Peakbagger.com. http://www.peakbagger.com/peak.aspx?pid=5176. Retrieved 2008-12-31.
  2. ^ a b c "Yellowstone". Global Volcanism Program, Smithsonian Institution. http://www.volcano.si.edu/world/volcano.cfm?vnum=1205-01-. Retrieved 2008-12-31.
  3. ^ As determined by geological field work conducted by Bob Christiansen of the United States Geological Survey in the 1960s and 1970s.
  4. ^ "Yellowstone Caldera, Wyoming—USGS". Cascade Volcano Observatory. United States Geological Survey. 2003-01-22. http://vulcan.wr.usgs.gov/Volcanoes/Yellowstone/description_yellowstone.html. Retrieved 2008-12-30.
  5. ^ Johnson, Stehen T.; Wynne, P. Jane; Hart, Craig J. R.; Enkin, Randolph J.; Engebretson, David C.; Engebretson, David C. (1996). "Yellowstone in Yukon: The Late Cretaceous Carmacks Group". Geology (Geological Society of America) 24 (11): 997, 998. doi:10.1130/0091-7613(1996)024<0997:YIYTLC>2.3.CO;2. ISSN 0091-7613.
  6. ^ "Yellowstone hotspot track". Lamont-Doherty Earth Observatory. http://www.ldeo.columbia.edu/~manders/SRP_erupt.html. Retrieved 2010-06-10.
  7. ^ Breining, Greg, Super Volcano: The Ticking Time Bomb beneath Yellowstone National Park (St. Paul, MN: Voyageur Press, 2007). ISBN 978-0-7603-2925-2
  8. ^ Newhall and Daniel Dzurisin, 1988, Historical Unrest at Large Calderas of the World: U.S. Geological Survey Bulletin 1855
  9. ^ This qualitative statement is easily verified by reviewing the Yellowstone area in Google Earth
  10. ^ "Origin and evolution of silicic magmatism at Yellowstone". http://pages.uoregon.edu/bindeman/Bindemanetal2008.pdf.
  11. ^ "Secrets of supervolcanoes". http://pages.uoregon.edu/bindeman/Supervolcanoes.pdf.
  12. ^ "Introduction to hydrothermal (steam) explosions in Yellowstone.". Yellowstone National Park. Yellowstone Net. http://www.yellowstone.net/hydrothermal.htm. Retrieved 2008-12-31.
  13. ^ a b c Jacob B. Lowenstern; Robert L. Christiansen, Robert B. Smith, Lisa A. Morgan, and Henry Heasler (2005-05-10). Steam Explosions, Earthquakes, and Volcanic Eruptions—What’s in Yellowstone’s Future? - U.S. Geological Survey Fact Sheet 2005-3024. United States Geological Survey. http://pubs.usgs.gov/fs/2005/3024/. Retrieved 2008-12-31.
  14. ^ Magma rising
  15. ^ "Yellowstone National Park Earthquake listings". http://www.quake.utah.edu/EQCENTER/LISTINGS/OTHER/yellowregion.htm. Retrieved 2010-02-01.
  16. ^ "Yellowstone Earthquake Swarms". Yellowstone Volcanic Observatory. http://volcanoes.usgs.gov/yvo/publications/2004/apr04swarm.php. Retrieved 2009-01-01.
  17. ^ a b "January 2010 Yellowstone Seismicity Summary". http://volcanoes.usgs.gov/activity/archiveupdate.php?noticeid=5199. Retrieved 2010-02-01.
  18. ^ "Archive of Yellowstone Updates for 2009". http://volcanoes.usgs.gov/yvo/activity/archive/2009.php.
  19. ^ "UUSS Webicorder (Seismogram) at Lake for December 31, 2008". http://www.seis.utah.edu/helicorder/heli/yellowstone/Uuss.LKWY_SHZ_US.2008123100.gif. Retrieved 2009-01-01.
  20. ^ Johnson, Kirk (2010-02-01). "Hundreds of Quakes Are Rattling Yellowstone". The New York Times. http://www.nytimes.com/2010/02/01/science/01yellowstone.html?partner=rss&emc=rss. Retrieved 2010-02-01.
  21. ^ "Undine Falls, Lava Creek, Yellowstone National Park". United States Geological Survey. http://volcanoes.usgs.gov/yvo/images/20010519-082_caption.html. Retrieved 2009-01-02.
  22. ^ John Timmer (2007-11-08). "Yellowstone recharges". arstechnica.com. http://arstechnica.com/journals/science.ars/2007/11/08/yellowstone-recharges. Retrieved 2007-11-08.
  23. ^ Smith, Robert B.; Wu-Lung Chang, Lee Siegel (2007-11-08). "Yellowstone rising: Volcano inflating with molten rock at record rate". Press release, University of Utah Public Relations (EurekAlert! (American Association for the Advancement of Science)). http://eurekalert.org/pub_releases/2007-11/uou-yr103007.php. Retrieved 2007-11-09.
  24. ^ Molten Rock Fills Yellowstone Volcano at Record Rate Newswise, Retrieved on September 2, 2008.
  25. ^ "Recent ups and downs of the Yellowstone Caldera". Yellowstone Volcano Observatory. United States Geological Survey. 2008-09-28. http://volcanoes.usgs.gov/yvo/publications/2007/upsanddowns.php. Retrieved 2008-12-31.
  26. ^ Smith, Robert B.; Jordan, Michael; Steinberger, Bernhard; Puskas, Christine M.; Farrell, Jamie; Waite, Gregory P.; Husen, Stephan; Chang, Wu-Lung; O'Connell, Richard (20 November 2009). "Geodynamics of the Yellowstone hotspot and mantle plume: Seismic and GPS imaging, kinematics and mantle flow". Journal of Volcanology and Geothermal Research 188 (1-3): 26–56. doi:10.1016/j.jvolgeores.2009.08.020. http://www.uusatrg.utah.edu/PAPERS/smith_jvgr2009complete.pdf.
  27. ^ http://volcanoes.usgs.gov/yvo/activity/archive/2009.php
  28. ^ http://volcano.wr.usgs.gov/yvostatus.php
  29. ^ http://pboweb.unavco.org/shared/scripts/stations/?checkkey=WLWY&sec=timeseries_plots&timeseries=raw
  30. ^ "Frequently asked questions about recent findings at Yellowstone Lake". Yellowstone Volcano Observatory. United States Geological Survey. 2008-09-11. http://volcanoes.usgs.gov/yvo/publications/2003/LakeQA.php. Retrieved 2008-12-31.
  31. ^ "Tsunami linked to Yellowstone crater". USA Today. 2008-01-14. http://www.usatoday.com/tech/science/2008-01-14-tsunami-yellowstone_N.htm. Retrieved 2008-12-31.
  32. ^ "Quake in Alaska Changed Yellowstone Geysers". University of Utah. 2004-05-27. http://unews.utah.edu/p/?r=030306-10. Retrieved 2008-12-31.
  33. ^ Yellowstone is being monitored
  34. ^ Foulger, Gillian (2006-02-08). "Yellowstone". MantlePlumes.org. http://www.mantleplumes.org/Yellowstone.html. Retrieved 2008-02-10.
  35. ^ Christiansen, Robert L.; G.R. Foulger, and John R. Evans (2002-10). "Upper-mantle origin of the Yellowstone hotspot". Geological Society of America Bulletin (Geological Society of America) 114 (10): 1245–1256. doi:10.1130/0016-7606(2002)114<1245:UMOOTY>2.0.CO;2. http://www.gsajournals.org/perlserv/?request=get-abstract&doi=10.1130%2F0016-7606(2002)114%3C1245:UMOOTY%3E2.0.CO%3B2. Retrieved 2008-12-31.
  36. ^ See list of off-line references in mantleplumes.org/CRB.html
  37. ^ Ivanov, Alexei V. (2007-02-07). "The Columbia River Flood Basalts: Consequence of subduction-related processes". MantlePlumes.org. http://www.mantleplumes.org/Yellowstone.html. Retrieved 2008-12-31.

[edit] Further reading

[edit] External links


The explosion also spewed volcanic ash over half of the United States, reaching areas of as far away as Texas, Louisiana and southern California, according to the U.S. Geological Survey.

Yellowstone’s many attractions include geysers, such as Old Faithful, and hot springs. These are believed to be a result of the giant pool of magma that Yellowstone sits on.

Some call the enormous underground caldera, which measures approximately 28 by 47 miles, a “supervolcano.” The UnMuseum explains that supervolcano isn’t exactly a technical scientific term, but says it differs from a traditional volcano “in that there is often no mountain peak associated with it.”

The lack of a peak or potential outlet for gas, heat and pressure building underground increasess the likelihood that “the entire surface above the underground chamber, which can be many miles wide, is blown away by a titanic explosion that can be thousands of times more powerful than that of a regular volcano.”

Volcanic eruptions can’t be predicted, and scientists wonder when Yellowstone will blow again. According to LiveScience, the caldera last blew up about 600,000 years ago.

Projections suggest that such an eruption would be catastrophic to most of the United States, with half the country being “covered in ash up to 3 feet deep,” LiveScience says, adding, “But those same researchers say nothing suggests such an eruption is imminent. They point out, however, that Yellowstone seems to blow its top about every 600,000 years.”

According to a BBC feature on such volcanoes, after an eruption, “The sky will darken, black rain will fall, and the Earth will be plunged into the equivalent of a nuclear winter.

The Cascades Volcano Observatory calls the Yellowstone caldera “one of the largest and most active in the world.” The United States has other, smaller calderas throughout the west.

Supervolcanoes are also found in other parts of the world, according to the Discovery Channel. They include a 1,000-square-mile caldera in Bolivia, and Lake Toba in Indonesia, which the Discovery Channel describes as the world’s largest at 1,080 square miles.

Reactions: How doomed are we?

Jake Lowenstern, Ph.D., Yellowstone Volcano Observatory’s chief scientist, who is also a member of the U.S. Geological Survey’s Volcano Hazards Team, does not think a supervolcano eruption will occur soon, according to U.S. News & World Report. “We don’t think the amount of magma exists that would create one of these large eruptions of the past,” he said. “It is still possible to have a volcanic eruption comparable to other volcanoes. But we would expect to see more and larger quakes, deformation and precursory explosions out of the lake. We don’t believe that anything strange is happening right now.”

On the other hand, Time magazine quotes a passage from Bill Bryson’s “A Short History of Nearly Everything,” in which Yellowstone geologist Paul Doss indicates to Bryson that an eruption could very well happen now, for the simple fact that “Nobody was around the last time it blew, so nobody knows what the warning signs are.” There may be sporadic earthquakes, strange geyser patters or a lifting of the surface, but “nobody really knows.”

Reference: National parks and Montana travel; interactive lesson on calderas

FindingDulcinea’s Web Guide to National Parks covers the history of the nation’s parks, such as Yellowstone, along with Web sites to help you plan a trip there.

Source: findingDulcinea


Could Yellowstone National Park’s caldera super-volcano be close to eruption?

By Daniel Bates
Created 10:54 AM on 25th January 2011

Read more: http://www.dailymail.co.uk/travel/article-1350340/Super-volcano-Yellowstones-National-Park-soon-erupt.html#ixzz1p8vhVfY2

regarding the possibility of the Yellowstone Cauldera blowing, spewing several cubic miles of ash in aSupervolcano event. Ashfall would go as far as New York. Where I am at in the midwest we would have several inches of volcanic ash.

Anyone breathing in dangerous amounts of ash would sufficate due to the concrete like substance that would form in thier lungs. The sky would darken, and we would be plunged into a Volcanic Winter scenario.

Not the end of life as we know it, just the end to a lot of lives.

Slumbering Giant
By Steve Connor
Science Editor
The Independent - UK
When the supervolcano that lies beneath Yellowstone National Park in Wyoming finally awakes from its 640,000-year slumber, it will spew out enough ash and magma to change the world as we know it. This is the prediction of scientists who have calculated that the global risk posed by a supervolcanic eruption somewhere in the world is between five and ten times greater than the probability of being struck by a giant asteroid.
But it is the huge lake of molten magma lying dormant under the lush landscape of Yellowstone that is causing the greatest concern to vulcanologists studying the special threat posed by supervolcanoes.
Earth scientists commissioned by the Geological Society of London have calculated that there may be several super-eruptions big enough to cause a global disaster every 100,000 years - whereas an asteroid larger than 1km (0.62 miles) in diameter would be expected to hit the Earth once in about 600,000 years.
Supervolcanoes may not look much - most do not even have the traditional cone of a Vesuvius or a Mount St Helens - but their potential for destruction is many times greater than a traditional volcanic eruption.
A super-eruption at Yellowstone would be far more devastating for the world than the eruptions at Tambora in 1815, Krakatoa in 1883 and Pinatubo in 1991 which all caused global climate disturbances for several years after the event. Super-eruptions are hundreds of times larger than the
biggest volcanic explosions of recorded history and their effects on the global climate are much more severe, said Professor Stephen Self, a vulcanologist at the Open University.
"An area the size of North America can be devastated and pronounced deterioration of global climate would be expected for a few years following the eruption," Professor Self explained. "They could result in the devastation of world agriculture, severe disruption of food supplies and mass starvation. These effects could be sufficiently severe to threaten the fabric of civilisation."
A two-part drama-documentary - Supervolcano - to be transmitted this Sunday and Monday on BBC1 spells out what could happen if the supervolcano under Yellowstone National Park should erupt in the near future. The programme makers worked closely with volcano specialists, including scientists at the US Geological Survey, who are closely monitoring Yellowstone, to depict the most realistic scenario leading up to and in the immediate aftermath of a massive eruption.
It shows what would happen if some 2,000 million tons of sulphuric acid were ejected into the atmosphere to block out sunlight over much of the planet causing global temperatures to plummet by between 10C and 20C.
It also describes the chaos and panic caused by the dumping of billions of tons of volcanic ash over huge swaths of North America. Scientists calculate that it would be equivalent to covering an area the size of Britain in four metres of ash.
Ailsa Orr, the series producer, said the film-makers consulted the US Federal Emergency Management Agency (Fema), which handled the aftermath of the 11 September terror attack on New York and Washington, and found there was little planning for such a natural disaster.
"Fema had no contingency plans for a disaster on this scale. The largest disaster they ever had to deal with was 9/11 and that stretched their resources to the limit," Ms Orr said.
"Our scenario would affect an area 10 million times greater than 9/11 did. Fema were extremely interested in working with us to come up with a theoretical plan as to how they might deal with it. They gave us data on how many people would be affected by the eruption in the US."
Satellite images show that the mouth or caldera of the Yellowstone supervolcano is 85km (53 miles) long and 45km (28 miles) wide - which amounts to an area big enough to swallow Tokyo, the largest city in the world.
Five miles underneath the surface of Yellowstone sits the volcanic chamber itself which is estimated to hold 25,000 cubic kilometres of molten rock or magma. Seismologists and vulcanologists working for the Yellowstone Volcano Observatory routinely monitor the regular swellings and subsidences of the land as it responds to shifting underground lake of molten rock below.
Ms Orr said that the makers of the drama-documentary liaised closely with the scientists at the observatory as well as other specialists and consultants. "We started by examining data from the first super-eruption of Yellowstone which happened 2.1 million years ago. We also looked at the evidence of the last supervolcanic eruption on the planet which happened at Toba in Indonesia 74,000 years ago," she added.
Some scientists believe that the Toba eruption, which caused global climatic disturbances, may have even caused a genetic "bottleneck" in human genetic diversity following a dramatic decline in the global population. If the Yellowstone supervolcano were to erupt in a similar fashion the ash that it would spew out would cover three-quarters of North America in a layer deep enough to kill crops and other plants.
Few people would survive in the zone immediately around the eruption as the volcanic gases and choking sulphur dioxide would burn the lungs of anyone caught in the open air. Those sheltering in their homes would not be safe because layers of heavy volcanic ash would eventually cause their roofs to collapse.
The supervolcanic eruption of the Toba volcano in Sumatra ejected about 300 times more volcanic ash than the eruption of Tambora in Indonesia in 1815 - which caused a "year without a summer" in 1816 and prompted Lord Byron to write his poem "Darkness".
A report on supervolcanoes compiled by the Geological Society states: "It is easy to imagine that an eruption on the scale of Toba would have devastating global effects. A layer of ash estimated at 15 cm thick fell over the entire Indian subcontinent with similar amounts over much of south-east Asia. Most recently, the Toba ash has been found in the South China Sea, implying that several centimetres also covered southern China.
"Just one centimetre of ash is enough to devastate agricultural activity ... Many millions of lives throughout most of Asia would be threatened if Toba erupted today," it says.
Ms Orr said the University of Utah and the UK Met Office had helped to compile a map of the fallout that might result from the eruption of ash from the Yellowstone supervolcano.
"From this, we created an ash projection map which took into account wind direction and time of year of our eruption. Every time we refined our storyline we would send it back to them for approval so they were closely involved," she said.
But it is the emission of sulphuric acid into the atmosphere that would create the greatest long-term problems for countries further afield, as the biggest volcanic eruptions of the past 200 years have shown, warns Professor Steve Sparks of Bristol University, a consultant to the programme. "They caused major climatic anomalies in the two or three years after the eruption by creating a cloud of sulphuric acid droplets in the upper atmosphere. These droplets reflect and absorb sunlight, and absorb heat from the Earth - warming the upper atmosphere and cooling the lower atmosphere," Professor Sparks said.
"The global climate system is disturbed, resulting in pronounced, anomalous warming and cooling of different parts of the Earth at different times."
If enough sulphuric acid were released - and Yellowstone could emit 2,000 million tons - then what could take place would be the equivalent of a "nuclear winter", when the dust and debris from the fallout of a nuclear war block out sunlight for several years causing worldwide famines.
The Max Planck Institute in Hamburg helped the makers of Supervolcano to model the spread of sulphuric acid around the world.
"We're talking about catastrophic amounts of sulphuric acid circling the world within just a few weeks. It forms a veil that blocks out sunlight, causing temperatures to plummet," Ms Orr said.
"The Met Office models predicted a drop of about 15C across Europe and 20C in the southern hemisphere, the monsoon would stop, crops would fail and somewhere in the region of one billion people would die through climate change and starvation," she added.
Supervolcano depicts the Yellowstone caldera erupting over several days, progressively "unzipping" the build-up of underground pressure in a series of eruptions around the rim of the crater rather than releasing everything all at once in one giant eruption.
Ms Orr said: "The first thing we had to get right was to understand the dynamics of a super-volcanic eruption - how it would unfold, what it would look like. It's very difficult to know for sure because nobody has ever seen a super-eruption happen but we consulted with a lot of scientists and the consensus of opinion was that a super-eruption is not just one big massive eruption but a series of separate eruptions around the rim of the caldera.
"Only towards the end of the eruption process do they all converge into one. Once this scenario had been signed off by the scientists, we got a storyboard artist to visualise it so everyone was clear on what we had to create in the film."
Nobody knows whether a supervolcanic eruption at Yellowstone is imminent. The programme-makers say at the start of their film that they have not made fiction, and they have made a true story - it's just that it hasn't happened yet.
The Yellowstone supervolcano is know to have erupted three times in the past 2.1 million years at a regularity of about 600,000 years. The last one happened 640,000 years ago.
Yet vulcanologists such as Professor Sparks point out that this does not mean that another eruption is overdue. "It doesn't work like that. We just don't know when the next eruption will occur," he said.
Neither do scientists know how much warning the world will be given. "Frankly we don't really know, that's the real problem," Professor Sparks said.
But what we do know is that we are ill-prepared for such an event if it should take place in the near future. "You can't stop it. One could have to start to think about the strategies for dealing with consequences and to be frank, that's not been thought through at all," Professor Sparks said.
One thing remains certain in this uncertain world of low-risk, high-impact disasters. If the Yellowstone supervolcano should ever blow, our world will never be the same again, and might not even survive in its present form.
According to scientists, the risk of a super-eruption somewhere in the world is five to 10 times greater than that of the world being hit by an asteroid. How does that compare with the other dangers we face daily?
The chances of being killed by being struck by lightning is thought to be about one in 10 million. In the UK, an estimated five people, out of a population of about 50 million, are killed by lightning each year.
Air crash
The chances of being involved in an aircraft accident are about one in 11 million, while the chances of being killed in a car accident is one in 8,000.
Train crash
The risk of dying in an accident on the railway is one in 500,000.
Nuclear accident
The risk of an individual dying from radiation from a nuclear power station is one in 10 million.
Dangerous jobs
The occupational risk of being killed in deep-sea fishing is one in 750. With coal mining, it is one in 7,500. In construction, this increases to one in 10,000, and for the service industries, it is one in 150,000.
Playing football
The risk of dying while playing a game of football is one in 25,000.
Asteroid collision
Some scientists believe that an asteroid spotted in January 2004 had a one-in-four chance of hitting the planet within 36 hours. Researchers contemplated a call to President George Bush before new data finally showed there was no danger. The bookmakers William Hill, meanwhile, said the odds of the asteroid hitting Earth on March 2014 and wiping life off the planet was 909,000 to one.
©2005 Independent News & Media (UK) Ltd.