The is the first ever established National Parkin North America. It was established in 1872 and occupies 2.2 millionof acres in southwestern Montana and northwestern Wyoming. The parkis found at high latitudes in the continental divide situated withinthe Rocky Mountains. It sits on the high plateaus averaging about8,000 feet above sealevel. The park comprises of two known rivers, namely, the SnakeRiver and the Yellowstone River. The park forms the core of theGreater Yellowstone Ecosystem (GYE) which is approximately 18 millionacres of land encompassing portions of the Montana, Wyoming, andIdaho. The GYE consists of five natural forests, wildlife refuges,and two national parks. Due to its biodiversity, the park wasdeclared an International Biosphere Reserve in 1976 and a WorldHeritage Site in 1978. The unique ecosystem, geological features, andbiodiversity are connected to the geologic history of YellowstoneNational Park. Tectonic activity, glaciation and most importantly,volcanism, have tremendously influenced the landscape and life in thepark for millions of years
Yellowstoneplume lies beneath the plateau and has been tomographically imaged asa slanted body that extends from 80 km beneath to 660 km beneathMontana. The Geodynamic modeling of the plume discovered that it ishotter than the mantle surrounding it. In this state, it is moremelted. Hence, it assumes a small buoyancy of 0.25MG/s. The plume hadinitially assumed a vertical position as it ascended down the mantlebeneath. The plume passed underneath the North American plate andfollowed the eastward upper mantle return flow, this ensued in achange of volcanic activity to the southeast. This also resulted intoeruptions that were caused by melting of the plate (Smith et al.,2009). As the North America plate shifted in a southwest direction,hotspot volcanism spread to the northeast. This slow and steadymovement has left its mark on the landscape. An evidence marked bythe plate’s progression is the flat-lying basalt volcanic flowingacross the Snake River Plain in Idaho within the park. Presently, theNorth America Tectonic Plate moves in a southwesterly direction atabout 1.8 cm per year. The Snake River plain shows millions of yearsof activity that took place as the plate glided over the magmahotspot which is relatively fixed.
YellowstoneVolcanism is one of the most active in history it is also the mostrecent. In mid-2004, the Yellowstone caldera displayed anextraordinary incident of the ground rising this was established byGPS and InSAR. These are Global Positioning and InterferometricSynthetic Aperture Radar respectively(Chang et al., 2007). Theuplifts in the caldera were recorded as magmatic recharge of theYellowstone magma body. Whereas the phenomena do not necessarilyindicate a forthcoming volcanic eruption or explosion, they areessential indicators that the caldera is still active and thepresence of volcanic activity beneath in the mantle. The area is alsomarked with breathtaking geysers, mud pots, boiling hot springs thathave made Yellowstone famous. There are over 10,000 thermal featureswith 300-500 active geysers within the park this is about 55% of theworld`s geysers. These are evidence of the magma activity beneaththat acts a continued heat source not far from the surface of theearth.
Theearth’s crust underneath Yellowstone in comprised of basalt andrhyolite, hence it is referred to as basaltic-rhyolitic magma. TheRhyolitic aspect contains high silica content, highly viscous hencegases cannot find its way out easily this has resulted in highlyexplosive activities. Basalts have low silica content they have lowviscosity, and hence they are thin, and their flow is faster. Gasescan easily escape in basaltic magma hence their eruptions are not asexplosive as Rhyolitic Volcanoes. The basaltic-rhyolitic mixtureresults in an intermediate form of magma. Silica found in rhyoliticmagma is harnessed for the manufacture of glass.
Yellowstoneis a caldera type of volcano. Over the past 2 million years, volcanicactivity in the region has built Yellowstone Plateau Volcanic Field-an immense plateau that spans the high mountain divide. The regionhas experienced three cycles of high volume outpouring of volcanicash, and rhyolitic lava, Each of the cycles was characterized by oneof the world`s greatest volcanic pyroclastic flow eruptions thatresulted in the collapse of the central part forming a large caldera.Succeeding eruptions generated other calderas along the volcanicpath. However, the younger basalt lava flows buried them and formed ablanket that covers the Snake River Plain (Program, 2016).
Howoften the Yellowstone Volcano Erupted, precursors to the majoreruptions and description how they erupted
Asmentioned above, Yellowstone has experienced three major explosiveeruptions in the past 2.1 million years with a recurrence interval ofabout 600,000 -800,000 years. Frequent precursors had occurred beforethe formation of the caldera these were frequent eruptions of basaltand rhyolite lava flows. The frequent eruptions have also beenexperienced after the large caldera-forming events. It has beenestablished by scientists that there have been at least 27 differentrhyolite lava flows having erupted in the last 640,000 years,Majority of these eruptions were separated by time intervals ofseveral tens of thousands of years, with the most recent being 70,000years ago.
Descriptionof the major eruptions
Thefirst large caldera-forming eruption happened 2.1 million years ago.The eruption resulted in a large volume of rocks known as theHuckleberry Ridge approximately measured 600 cubic miles. Thiseruption created a huge crater which measured up to 80 km long, 65 kmwide and hundreds of meters deep in the extending outside. Later, volcanic activity shifted to the southwestside of the park into a smaller region within the Island Park ofeastern Idaho. This activity generated another huge caldera-formingeruption 1.3 million years ago. This formed the Island Park Caldera.Being the smallest of the three eruptions, it overlays the westernpart of the Huckleberry Ridge eruption ("YellowstoneSuper Volcano", 2016). Thelast large eruption known as the Lava Creek happened 640,000 yearsago. It overlays the Huckleberry Ridge, expanding 10 km eastwardtowards the boundary of the original caldera. As compared to the mostrecent Volcanic eruption of Mount Saint Helens that happened in 1980,producing a quarter mile of a cubic mile of rock, the HuckleberryRidge eruption was 2,400 times larger.
Effectsof the Eruption on People and Environment, hazards associated withthe eruptions
Duringthe three giant-caldera forming eruptions, tiny particles of volcanicdebris, otherwise known as volcanic ash, covered much of the half ofNorth America to the west. Sulfur aerosol and lightest ash particleswere carried by the wind around the globe, and it likely caused anoticeable drop in temperatures worldwide. The last most devastatingeruption of a super volcano was in Toba, 75,000 years ago. Thousandsof cubic miles of ash thrown into the earth’s atmosphere blockedout sunlight all over the globe temperatures rapidly dropped,thousands of miles away, inches of ash covered the surface, Gases inthe atmosphere caused poisoning and formed acid rain that was blackin color. Most of the plants found in the northern hemisphere werekilled ("Yellowstone Super Volcano," 2016). The human kind population soon decreased, and it was at the edge ofextinction. Similar effects will be experienced if an eruption ofthat magnitude happens now.
Possibleoutcomes of another Yellowstone Volcanic Eruption and what has beenlearnt from previous eruptions
IfYellowstone erupts with the same scale as the large caldera-formingeruptions did, it will be totally catastrophic especially to thepeople living in North America. The lava flow will not be much of athreat as the previous ones that have never gone further beyond thepark boundaries. The biggest threat posed by the possible eruption,as established by volcanologists, is the ash that is flung into theair and spread by wind to the furthest regions away from the volcanicfield. Predictions by scientist state that, the ash would be sodevastating for the United States, with a covering of 4 inches abovethe ground. Hazards associated with this are first, the short-termeffects that would be seen immediately, they would include thedestruction of Midwest agriculture, streams and rivers would beclogged by gray-black debris. The eruption’s fallout would chokepeople living in North America. The atmosphere will be polluted withvast quantities of sulfur dioxide, a smelly gas that absorbs sunlightand bounces back some of it back into space. This will result inmassive temperature drops that could last up to a decade. Climatechange will be experienced as the rainfall patterns would be altered.This together with severe frost due to cold temperatures, would causehuge crop losses that might lead to famine. From the previoussupervolcanic actions that have left the face of the earth and thepeople in it devastated, there is still much to learn about theglobal effects. Little has been learned to curb such events becausethese huge eruptions happened a long time ago and the scientists donot have much detail about them and their consequences (Program,2006)
CurrentState and Concerns of the state of Yellowstone
Therecent activities such as the ground swelling in the caldera,day-to-day shaking of the park always portray a looming disasterwaiting to happen. This has been a scare to many people as thephenomena make them believe there might be a possible volcaniceruption soon. However, YVO has assured that these signs do notportend doom as it has never seen warning signs of an impendingeruption at the park.
WarningSystems in place
U.S.Geological Survey`s Yellowstone Volcano Observatory (YVO) and theUniversity of Utah have been set up to keep watch on the activitiesin the Yellowstone Park. The scientistsare constantly on the look for any possible signs of eruptions. Theyare looking for any distinctive earthquakes that are normallytriggered by molten rock shifting its position. Magma movingunderground sets off seismic waves that are different from thosecaused by splitting fault lines. This team of scientist will have agood idea if magma is finding its way to the surface. Real-time datafrom scientists continuously monitoring volcanic activity isavailable through websites and news releases. Currently, real-timemonitoring is online (Program, 2016).
Scientistsprobe that eruptions will be detectable for weeks or even months,hence there ill be enough time for issuing a warning. The YVO willcommunicate accurately and in a timely manner to the surroundingcommunities, media outlets and any other party that is interested. Itwill also do necessary communication to the local government andstate agencies (Program, 2016).
Chang,W. L., Smith, R. B., Wicks, C., Farrell, J. M., & Puskas, C. M.(2007). Accelerated uplift and magmatic intrusion of the Yellowstonecaldera, 2004 to 2006. Science, 318(5852),952-956.
Program,V. (2016). USGS:Volcano Hazards Program YVO Yellowstone.Volcanoes.usgs.gov.Retrieved 25 August 2016, fromhttps://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_geo_hist_52.html
Smith,R. B., Jordan, M., Steinberger, B., Puskas, C. M., Farrell, J.,Waite, G. P., … & O`Connell, R. (2009). Geodynamics of theYellowstone hotspot and mantle plume: Seismic and GPS imaging,kinematics, and mantle flow. Journalof Volcanology and Geothermal Research, 188(1),26-56.
YellowstoneSuper Volcano. (2016). Greater-yellowstone.com. Retrieved25 August 2016, fromhttp://www.greater-yellowstone.com/Yellowstone-Park/Yellowstone-Super-Volcano.html