Sabtu, 19 November 2011

Volcano Yellowstone

Yellowstone Volcano is one of a series of active volcanoes located on the west coast of the United States. Mountains of fire in this region is part of a ring of fire thatsurrounds the Pacific Ocean, and into areas prone to earthquakes. YellowstoneVolcano storing wealth of flora, animal and amazing natural beauty, so designated as nature conservation area in the world's first-named Yellowstone National Park. Yellowstone National Park is a national park in the United States Located in the state of Wyoming, Montana, and Idaho. Covering 3468 square miles (8983 km ²).Yellowstone National Park is the world's oldest national park, established on March 1,1872 when the leadership of U.S. President Ulysses S. Grant. 
Yellowstone National Park is famous for its geysers and hot springs. World famousgeyser, Old Faithful Geyser, is here. Here also live grizzly bears, wolves, bison anddeer. Many tourists visit this place to witness the lives of wildlife and natural beauty. 
The Yellowstone Plateau volcanic field developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions. Eruption of the >2450 cu km Huckleberry Ridge Tuff about 2.1 million years ago created the more than 75-km-long Island Park caldera. The second cycle concluded with the eruption of the Mesa Falls Tuff around 1.3 million years ago, forming the 16-km-wide Henrys Fork caldera at the western end of the first caldera. Activity subsequently shifted to the present Yellowstone Plateau and culminated 640,000 years ago with the eruption of the >1000 cu km Lava Creek Tuff and the formation of the present 45 x 85 km caldera. Resurgent doming subsequently occurred at both the NE and SW sides of the caldera and voluminous (1000 cu km) intracaldera rhyolitic lava flows were erupted between 150,000 and 70,000 years ago. No magmatic eruptions have occurred since the late Pleistocene, but large phreatic eruptions took place near Yellowstone Lake during the Holocene. Yellowstone is presently the site of one of the world's largest hydrothermal systems including Earth's largest concentration of geysers. 

Location: Western US, WY 
Latitude: 44.43
Longitude: -110.67 
Elevation: 2805 m 

Yellowstone's world-famous natural history is marked by such colossal volcanic events that their reflections in today's landscape are difficult to grasp and impossible to take in at just a glance, even for those familiar with the signs of past volcanism. The stunning features of Yellowstone National Park result from great explosive eruptions and profound collapse of the ground, enormously thick lava flows, uplift and extensive faulting, and the erosive power of flowing water and ice. For more than a century, geologists have discovered and analyzed evidence of the dramatic events that have shaped the land here. When combined with growing knowledge about how volcanoes work and the never-ending motion of Earth's surface, the evidence tells a remarkable story of the Yellowstone landscape. 

The stunning features of Yellowstone National Park result from great explosive eruptions and profound collapse of the ground, enormously thick lava flows, uplift and extensive faulting, and the erosive power of flowing water and ice. For more than a century, geologists have discovered and analyzed evidence of the dramatic events that have shaped the land here. When combined with growing knowledge about how volcanoes work and the never-ending motion of Earth's surface, the evidence tells a remarkable story of the Yellowstone landscape. 

The volcanism most directly identified with the Yellowstone region has, during about the past 2 million years, built an immense volcanic plateau that straddles a high mountain divide—the Yellowstone Plateau volcanic field. This volcanic region has evolved through 3 cycles of voluminous outpourings of rhyolite lava and volcanic ash, each of them climaxing with one of Earth's greatest pyroclastic-floweruptions and the resulting collapse of a central area to form a large caldera. Other eruptions have poured out basalt lava flows around the margins of the volcanic field. 

Yellowstone's volcanism is only the most recent in a 17 million-year history of volcanic activity that has occurred progressively from southwestern Idaho to Yellowstone National Park. At least six other large volcanic centers along this path generated caldera-forming eruptions; the calderas are no longer visible because they are buried beneath younger basaltic lava flows and sediments that blanket the Snake River Plain.  
In the 1970s, a resurvey of benchmarks discovered the unprecedented uplift of the Yellowstone Caldera of more than 28 inches (72 cm) over five decades. More recently, new and revolutionary satellite-based methods for tracking the Earth's shifting ground motions have enabled University of Utah, US Geological Survey, and other scientists to assemble a more precise and detailed picture of Yellowstone's ground movements.

Reference: Wikipedia, volcanoes.usgs.gov


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