| Yellowstone
is the world’s largest hydrothermal area. The park is situated
at the centre of millions of years of volcanic activity and walking
in the thermal areas reinforces the feeling that you are very close
to the molten magma that exists close to the earth’s surface.
Indeed the geologists predict that Yellowstone is in fact an unexploded
bomb just waiting to erupt. They predict that in 2074 the volcanic
core of Yellowstone will erupt with such fury that the resultant ash
cloud will turn the Northern Hemisphere into permanent night for hundreds
of years and the exploding lava will destroy the land for hundreds
of miles in every direction.
Highly heated lava is
so close to the surface results in the spectacular hydrothermal
features to be found. The heat comes from either the primal magma
of the earth or from underground hot lava. No one knows just how
far below the surface this molten rock is, but a good estimate is
from 5,000 to 20,000 feet. One scientific team drilled to 265 feet
and found a temperature of more than 400 degrees Fahrenheit. This
temperature is well in excess for normal ground temperature at this
depth. It is the thermal area’s size and proximity to the
earth’s inner heat that sets Yellowstone National Park apart
from any place on earth. It is the water from rain and snow that
seeps down through the ground, which is heated, then comes forth
at the surface in the form of a geyser, a hot spring or a fumarole.
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