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| Composition of the Earth The Earth is composed of five sections: the atmosphere, the hydrosphere, and the remaining three, which we are concerned with here; the lithosphere, mantle, and core. The lithosphere is comprised of the crust and upper mantle. Between the upper mantle and the crust is the seismic discontinuity, called the Moho (Mohorovicic discontinuity), then between the upper and lower mantle a weak zone known as the asthenosphere. |
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 The asthenosphere is a 60 mile thick zone which is partially molten and is what allows for the continental drift. The core of the Earth is made up of two parts. The outer core, which research shows to be about 1400 miles thick and the inner core which is a mere 800 miles in radius and has temperatures reaching 6650�C (12,000�F). |
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How are mountains formed? The three most common mountain formations are the easily recognized volcanoes such as Mount St. Helens in North America and Mount Pinatubo in the Philippines, then fold mountains like the Himalayas in Asia and the Andes in South America and fault-block mountains, the Sierra Nevada mountains in North America and the Harz Mountains in Germany.
There are more than 850 active volcanoes on the Earth we currently know of, 80 or so of which are under the oceans. Whether by the constant non-violent flow of a Strombolian eruption or by means of a violent eruption accompanied by earthquakes, volcanoes create land mass. The slopes of volcanoes are often inhabited by people because of the rich, fertile soil produced, perhaps a consolation for living in the shadow of possible death and destruction. The world's largest, active volcano is Mauna Loa in Hawaii, where famous coffee is grown in the rich volcanic soils.
Fault-block mountains are formed when huge blocks of the Earth's crust are tilted on or pushed up along a fracture line, also known as a fault line.
Typically this occurs along the edge of one fault, but can happen between two separate faults. The tell tale mark of a fault-block mountain is the accumulation of debris at the base of a sharp face caused by the rapid erosion of the rock on one side and a usually gradual slope on the opposite side.
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The Himalaya mountain range of Asia is home to the highest mountain peak on Earth, Mount Everest, and subsequently makes the Himalayas one the most famous range of fold mountains on Earth. The Himalayas are also home to the second highest mountain, K2 (AKA Mount Godwin Austen or Dapsang). Fold mountains are created when continental plates collide with each other, or with oceanic plates, forcing massive layers of the Earth's crust upward, bending and crumpling rocks and the Earth's crust.
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