Planet Earth: Earthquakes, Mountains, Glaciers and More
About the planet Earth, earthquakes, Mount Everest, wobble on the axis, Antarctic glacier.
It has been established that the spinning earth actually does wobble on its axis at a maximum range of 72' over a 14-month period. Scientists say the earth's north-south axis zigs and zags around the geographical North Pole in a generally circular motion--much like a spinning top beginning to lose its speed. Telescopes are continually trained on the heavens by scientists in the U.S., Russia, Japan, and Italy to determine whether there is any uniformity to this wobble and what causes it. There are varying theories: 1) some believe it's due to the melting of the polar ice caps; 2) some think it's due to the uneven land masses; and 3) others say it's because of the movements of the seas. The astronomers train their telescopes on 18 pairs of stars agreed upon by the participating nations. They know the exact time each star will cross the meridian on which the telescope is trained. Four sightings of each star are made as it crosses the meridian. Then the angular distance is measured between a pair of stars to indicate the extent to which the earth has wobbled on its axis. Since mapmakers can't make wobble maps to show the shifting of the North Pole (much too small for most scales of mapping), they adopt a "mean pole" as a base for latitude and longitude.
Most of the water in the world's great river systems ultimately derives from the glaciers of Antarctica and Greenland. Approximately 3/4 of all the fresh water in the world (some 7 million cubic mi.) is stored in the form of glacial ice. This reserve is estimated to be equal to about 60 years' rainfall over the entire globe.
Mount Everest, the earth's highest peak (29,028'), located in the Himalayas, the highest of the world's mountain ranges, is so high at its summit that it penetrates the jet stream. Winds that sometimes reach 200 mph blow snow from its peak. The Himalayas--which merge with the Karakoram mountain range, the world's 2nd highest--together with the Karakoram range, boast over 500 peaks above 20,000'. North America has only one 20,000' peak (Alaska's Mount McKinley). The highest peak in Western Europe, Mont Blanc in the French Alps, rises up a mere 15,781'.
Earthquakes and volcanic eruptions are generally common in the same areas of the world. Italy, Japan, and Chile are the principal locations of both seismic and volcanic activity. The circum-Pacific belt (west coast margins of the Americas and the island archipelagoes of Asia) is the main earthquake zone, accounting for over 80% of the total energy released by earthquakes. The 2nd most active zone is the Alpine-Mediterranean-trans-Atlantic belt (North Africa, Spain, Italy, Greece, Turkey, Iran, northern India, and Burma), which accounts for 15%. This leaves only about 5% elsewhere in the world, most of it in submarine ridge areas of the Atlantic, Indian, and Arctic oceans.
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