Glacier Peak
Glacier Peak, overlooking the eastern slope
The Glacier Peak (English glacial peaks, in Sauk Dialect of Lushootseedsprache Tda -ko -buh -ba or Takobia ) in the north of the State of Washington, USA, is an active stratovolcano in the Cascade Range.
Unlike some other volcanoes in the Pacific Northwest of the Glacier Peak is not particularly visible from the nearest urban centers, and so its tourist attractions as well as its dangers are often overlooked. Here, the volcano has made some of the most violent eruptions in the area of Washington state since the last ice age. The eruptions took place at this time in six series, last 200 to 300 years ago. The Glacier Peak is located in Snohomish County about 100 kilometers northeast of Seattle, so little further from the city than Mount Rainier. But other than this, the volcano rises only up to 1000 m higher than the surrounding peaks, making it one of many in a series of high mountains, when viewed from the Puget sound.
Geology
The summit area, including the addition Summit Disappointment Peak ( summit of disappointment ), consists of the remains of Lavadomen from prehistoric times. On the mountain slopes remnants can be seen pyroclastic flows, particularly on the eastern slopes beyond traces of volcanic ash.
The mountain slopes have several miles of deposits of lahars and debris flows. The oldest 14,000 years deposit ranges about 35 km from the western slope and through the valley of the White Chuck River to its confluence with the Sauk River. At Glacier Peak are located approximately 1800 m altitude several spatter and cinder cones, also three thermal springs called Gamma, Kennedy and Sulphur.
The stratovolcano is the fourth highest mountain in Washington State. As part of the Cascade Volcanic Arc, he was created by the subduction of the Juan de Fuca Plate under the North American Plate. The plates converge at a rate of four inches per year. Despite the altitude of 3212 m, the Glacier Peak is quite small for a stratovolcano. The peak is so high because the actual volcano is located on a high mountain range. This volcanic part of the Glacier Peak is only 500 to 1000 m higher than the chain underneath.
Volcanic activity
Of the five highest volcanoes in Washington broke only the Glacier Peak and Mount St. Helens from within the last 15,000 years. Both form very viscous magma (see also: dacite ) which does not flow from the volcanic vent, but accumulates inside the mountain, which ultimately leads to an explosion. In such an event, especially pyroclastic sediments are discharged.
Means Tephrochronologie and radiocarbon dating has been determined that the Glacier Peak must be broken out around the year 1700, 1300, 900, 200, 850 BC, 3150 BC and 3550 BC. Three of the outbreaks were between stages 2 to 4 after Vulkanexplosivitätsindex. A characteristic feature of these outbreaks are a first eruption by the volcano vent, followed by a stronger explosion. What material was ejected, was different. Time created lahars, pyroclastic flows times, different outbreaks caused the emergence of Lavadomen.
In the river valleys to the Glacier Peak are several meters thick layers of Laharresten detectable, some dozens of kilometers from the slopes of the volcano. In the outbreaks before 5900 and 1800 years ago, the lahars came up in the Puget Sound. The pyroclastic sediments were deposited after the eruption partly in the vicinity, most of the ash but was transported in the form of clouds at high altitude and driven hundreds of miles away by the wind. The ash layers near the town of Chelan were 30 cm and in Missoula, Montana 7.6 mm high.
Glacier
Eleven major glaciers cover the summit area of Glacier Peak. When CE Rusk first saw this in 1906, they were already on the decline but still very extensive. From the Little Ice Age to 1958, the ice went on the Glacier Peak back to about 1640 meters in altitude. Richard Hubley noticed an increasing again glaciation since the early 1950s. Previously, the glaciers were melted for about thirty years very quickly. The increasing icing middle of the 20th century was due to significantly more frequent winter precipitation and falling summer average temperatures since 1944. The period of glaciation lasted until about 1979. However, from 1984 to 2005 is a decrease from an average of 310 m recorded. The Milk Lake Glacier on the northern slope of the Glacier Peak disappeared completely in the 90s.
History
The snow-capped volcanoes of Washington influenced the legends and the languages of the Native Americans and they directed the attention of the U.S. and European explorers in the late 18th and the early 19th century up. Already in the 1790s, Mount Baker, Mount Rainier and Mount St. Helens were mentioned in the first written descriptions of the regions of the Columbia River and Puget Sound. In 1805 Lewis and Clark Mount Adams noted. During the mid-19th century, the volcanoes were located in the maps.
The Glacier Peak, however, the settlers was not known, the naturalist George Gibbs described up in the 1850s indigenous people, another slightly smaller summit would north of Mount Rainier smoke. By 1898 a map was published in the Glacier Peak was entered.
Gallery
Aerial view from the southeast
View from the south