Emerald Pool, Black Sand Basin, Yellowstone National Park, Wyoming : 無料・フリー素材/写真
Emerald Pool, Black Sand Basin, Yellowstone National Park, Wyoming / Ken Lund
| ライセンス | クリエイティブ・コモンズ 表示-継承 2.1 |
|---|---|
| 説明 | South of Norris Geyser Basin along the rim of the Yellowstone Caldera is the Upper Geyser Basin, which has the highest concentration of geothermal features in the park. Biscuit Basin and Black Sand Basin are also within the boundaries of Upper Geyser Basin.The hills surrounding Old Faithful and the Upper Geyser Basin are reminders of Quaternary rhyolitic lava flows. These flows, occurring long after the catastrophic eruption of 640,000 years ago, flowed across the landscape like stiff mounds of bread dough due to their high silica content.The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles. The number of thermal features in Yellowstone is estimated at 10,000. A study that was completed in 2011 found that a total of 1283 geysers have erupted in Yellowstone, 465 of which are active during an average year. These are distributed among nine geyser basins, with a few geysers found in smaller thermal areas throughout the Park. The number of geysers in each geyser basin are as follows: Upper Geyser Basin (410), Midway Geyser Basin (59), Lower Geyser Basin (283), Norris Geyser Basin (193), West Thumb Geyser Basin (84), Gibbon Geyser Basin (24), Lone Star Geyser Basin (21), Shoshone Geyser Basin (107), Heart Lake Geyser Basin (69), other areas (33). The various geyser basins are located where rainwater and snowmelt can percolate into the ground, get indirectly superheated by the underlying Yellowstone hotspot, and then erupt at the surface as geysers, hot springs, and fumaroles. Thus flat-bottomed valleys between ancient lava flows and glacial moraines are where most of the large geothermal areas are located. Smaller geothermal areas can be found where fault lines reach the surface, in places along the circular fracture zone around the caldera, and at the base of slopes that collect excess groundwater. Due to the Yellowstone Plateau's high elevation the average boiling temperature at Yellowstone's geyser basins is 199 °F (93 °C). When properly confined and close to the surface it can periodically release some of the built-up pressure in eruptions of hot water and steam that can reach up to 390 feet (120 m) into the air (see Steamboat Geyser, the world’s tallest geyser). Water erupting from Yellowstone's geysers is superheated above that boiling point to an average of 204 °F (95.5 °C) as it leaves the vent. The water cools significantly while airborne and is no longer scalding hot by the time it strikes the ground, nearby boardwalks, or even spectators. Because of the high temperatures of the water in the features it is important that spectators remain on the boardwalks and designated trails. Several deaths have occurred in the park as a result of falls into hot springs.en.wikipedia.org/wiki/Geothermal_areas_of_Yellowstoneen.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_... |
| 撮影日 | 2007-08-09 15:51:03 |
| 撮影者 | Ken Lund , Reno, Nevada, USA |
| タグ | |
| 撮影地 | Old Faithful, Wyoming, United States 地図 |
| カメラ | Canon PowerShot A540 , Canon |
| 露出 | 0.002 sec (1/640) |
| 開放F値 | f/4.0 |
| 焦点距離 | 12515.55556 dpi |