Yellowstone Caldera
The Yellowstone is a very significant volcanic complex under the same National Park in the U.S. state of Wyoming.
- 5.1 Photos and Videos
- 5.2 Volcano Observatory
- 5.3 Scientific contributions
Volcanism
A suspected hot spot, that is, a zone that rises to the hot mantle material beneath the earth's crust, is at the origin of the approximately 17 million year old volcanic system at Yellowstone River. The North American plate has moved over these relatively entrenched hot spot, where the lithosphere was heavily modified by tectonic and magmatic processes. Same time, the over 700 -km-long Yellowstone - Snake River volcanic system, form the most visible traces of several calderas formed. Your tracks can be partially follow very clear.
The Mantle Plume has created a bulge of 400 km wide and 500 m altitude at the Yellowstone Plateau. In recent years, also be equipped with geodetic measuring deformation and subsidence, ie Bulge and sinking into the volcanic system accurately tracked. On average, thereby resulting movements of 2 cm per year. In the years 2004-2009, however, you could find an accelerated Aufwölbungsbewegung, which was interpreted as fresh magma intrusion in the horizontal courses above the actual magma chamber at depth of 10 km.
Up to 2,000 mostly weak earthquakes annually by the volcanic activity in the region conditionally registered.
Previously documented outbreaks
The Yellowstone hot spot
By getting on the hot spot shifting continental plates are about the millions of detectable traces of volcanic activity, in this case, a chain of calderas on the North American continent. The magma chamber located in approximately eight km depth is about 60 km long, 35 km wide, 8-10 km thick and heated underground water resources, which, as the Old Faithful, sometimes come to the surface as geysers.
Geological studies show that the Yellowstone hotspot is active for 17 million years and has shifted in this period as a result of plate tectonics, the Earth's surface so that the hot spot migrated apparently around 700 km from present-day northern Nevada across southern Idaho to its present location is. He created the bedrock of the Snake River Plain, leaving behind a basaltic - rhyolitic magma pocket, which caused a temporary elevation of 15 cm in the area of the Snake River.
The calder forming eruptions
The last three of the very large eruptions of the Yellowstone hotspot found in today's National Park or in its immediate environment before 2.1 million ( Huckleberry Ridge eruption ), 1.3 million ( Mesa Falls eruption ) and 0.64 million years ago instead of ( Lava Creek eruption ).
The strongest was the first of the three mentioned eruptions about 2.1 million years ago. Here, a caldera 50 km was about 80 ×. About 2,500 km ³ of material were ejected. However, recent studies suggest that the amount of material ejected during so-called Huckleberry Ridge eruption on not one but at least two, if not more eruptions are due, among which were 4000 years. Klemetti cited the article and mentioned a distribution on even three phases, which have each produced 1340 km ³, 820 km ³ and 290 km ³. Still very considerable quantities, but not as much as first thought by scientists.
The second eruption around 1.3 million years ago was the smallest of the three; only 280 km ³ of material were ejected.
The third series calderabildende eruption about 640,000 years ago created a total overlapping caldera of about 80 km and 55 km wide. The outbreak had been like the previous ones initiated by the activation of magmas in shallow magma chambers. In addition to enormous amounts of ash, traces extend to California, he produced, among other things numerous pyroclastic flows. The gains or losses arising ignimbrites are called Lava Creek Tuff and can be seen in the cliffs of the Madison Canyon.
Because of the strength of these outbreaks the Yellowstone volcano is considered one of the super volcanoes.
Subsequent eruptions in the system
After these big eruptions there was no rest, the following outbreaks were not nearly as catastrophic.
Tuffablagerungen of two subsequent explosive eruptions before 170,000 ( Bluff Point Tuff ) and 140,000 years ( Cold Mountain Creek Tuff ) show an ejected volume of 50 or 10 km ³, which accounts for more strength 6 on the Vulkanexplosivitätsindex.
More effusive rhyolitic Lavaausbrüche in the period from before 180,000 to 70,000 years ago filled with a total volume of 600 km ³ of the caldera from almost all over again and formed the present Yellowstone Plateau.
In the Holocene, there were smaller outbreaks each about 9,400 years ago on the Turbid Lake, 8,050 years ago on Elliot's Crater, 5,050 years ago at Duck Lake and the Evil Twin Craters and last 3,350 years ago at the Indian Pond Crater. This took the form of local steam explosions
Sequence of possible eruptions in the future
Even today has the Yellowstone still a large magma chamber, so that a similar large outbreak continues sometime seems possible. Geological changes, such as the lifting of the caldera structure in recent decades, have an outbreak in geologically near future - within the next millennia - appear likely. However, expecting the U.S. Geological Survey (USGS ), in the U.S., responsible for monitoring the system geological survey office, not the fact that it comes in the near future major outbreaks in the system. You expectations are for further interaction of the high-temperature areas, phreatic explosions, and moderate to severe earthquake activity.
Since 1995, appeared a new pattern of seismic activity. The USGS reported that the northern crater rim raised, while the base fell. These opposing movements rose steadily, came in 2003, but again almost to a standstill. Around the turn of the year 2008/2009 an accumulation of small and micro earthquake was observed until March 2009, the seismic activity was, however, arrived back on their long-term average level.
These movements are believed to be caused by the molten basalt flowing in the underground magma channels. In the 1990s, these were probably reinforced by the fact that a magma pushing out of the upper mantle flowed into the Yellowstone volcanic system. Because apparently flowed very little magma again, the pressure, creating new rock fissures emerged, which in turn created a better connection to the deeper magma reservoir increased. The movements led to increased geothermal activity in the area.
Such phases " thermal agitation " have, according to the scientists of the USGS have repeatedly taken place, so far without consequences in the recent past.
Movies
2005 was a mixture of BBC docudrama and fictitious disaster film shoot, which deals with the eruption of the Yellowstone. The film was entitled Supervolcano ( super volcano dt ).
On 12 November 2009 appeared Roland Emmerich's film 2012, which is, among others, from the eruption of super volcano.