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Volcanic Dam
A volcanic dam is a type of natural dam produced directly or indirectly by volcanism, which holds or temporarily restricts the flow of surface water in existing streams, like a man-made dam. There are two main types of volcanic dams, those created by the flow of molten lava, and those created by the primary or secondary deposition of pyroclastic material and debris. This classification generally excludes other, often larger and longer lived dam-type geologic features, separately termed crater lakes, although these volcanic centers may be associated with the source of material for volcanic dams, and the lowest portion of its confining rim may be considered as such a dam, especially if the lake level within the crater is relatively high. Volcanic dams generally occur worldwide, in association with former and active volcanic provinces, and are known to have existed in the geologic record, in historic times and occur in the present day. Their removal or failure is similarly recorded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RockSlide 1200W
A rockslide is a type of landslide caused by rock failure in which part of the bedding plane of failure passes through compacted rock and material collapses ''en masse'' and not in individual blocks. Note that a rockslide is similar to an avalanche because they are both slides of debris that can bury a piece of land. While a landslide occurs when loose dirt or sediment falls down a slope, a rockslide occurs only when solid rocks are transported down slope. The rocks tumble downhill, loosening other rocks on their way and smashing everything in their path. Fast-flowing rock slides or debris slides behave similarly to snow avalanches, and are often referred to as rock avalanches or debris avalanches. Definition The term landslide refers to a variety of mass wasting events (geologic slope failures) that include slumps, slides, falls, and flows. The two major types of slides are rotational slides and translational slides. Rockslides are a type of translational event since the rock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snake River Plain
The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges">gorges, such as this one near Twin Falls, Idaho The Snake River Plain is a geologic feature located primarily within the U.S. state of Idaho. It stretches about westward from northwest of the state of Wyoming to the Idaho-Oregon border. The plain is a wide, flat bow-shaped depression and covers about a quarter of Idaho. Three major volcanic buttes dot the plain east of Arco, the largest being Big Southern Butte. Most of Idaho's major cities are in the Snake River Plain, as is much of its agricultural land. Geology The Snake River Plain can be divided into three sections: western, central, and eastern. The western Snake River Plain is a large tectonic graben or rift valley filled with several kilometers of lacustrine (lake) sediments; the sediments are underlain by rhyolite and basalt, and overlain by basalt. The western plain began to form around 11–12 Ma (million years ago) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Surge
A pyroclastic surge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes it more turbulent and allows it to rise over ridges and hills rather than always travel downhill as pyroclastic flows do. The speed of pyroclastic density currents has been measured directly via photography only in the case of Mount St. Helens, where they reached 320-470 km/h, or . Estimates of other modern eruptions are around 360 km/h, or 100 m/s (225 mph). Pyroclastic flows may generate surges. For example, the city of Saint-Pierre in Martinique in 1902 was overcome by one. Pyroclastic surge include 3 types, which are base surge, ash-cloud surge, and ground surge. Base surge First recognized after the Taal Volcano eruption of 1965 in the Philippines, where a visiting volcanologist from USGS recognized the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clasts
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks by physical weathering.Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-5 Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits. Sedimentary clastic rocks Clastic sedimentary rocks are rocks composed predominantly of broken pieces or ''clasts'' of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. An example of clastic environment would be a river system in which the full range of grains being transported b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephra
Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they remain as tephra unless hot enough to fuse into pyroclastic rock or tuff. Tephrochronology is a geochronological technique that uses discrete layers of tephra—volcanic ash from a single eruption—to create a chronological framework in which paleoenvironmental or archaeological records can be placed. When a volcano explodes, it releases a variety of tephra including ash, cinders, and blocks. These layers settle on the land and, over time, sedimentation occurs incorporating these tephra layers into the geologic record. Often, when a volcano explodes, biological organisms are killed and their remains are buried within the tephra layer. These fossils are later dated by scientists to determine the age of the fossil and its place within the g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Butte
Lava Butte is a cinder cone in central Oregon, United States, just west of U.S. Route 97 between the towns of Bend, and Sunriver in Deschutes County. It is part of a system of small cinder cones on the northwest flank of Newberry Volcano, a massive shield volcano which rises to the southeast. The cinder cone is capped by a crater which extends about deep beneath its south rim, and deep from the summit on its north side. Lava Butte is part of the Newberry National Volcanic Monument. Volcanic history Like the other cinder cones in the area, Lava Butte only experienced a single eruption, dated by geologists in 1977 to 6,150 carbon-14 years, equivalent to about 7,000 years ago. The eruption began with a fissure spewing hot cinders to form the cone. In the next phase, a river of hot basalt flowed from the base of the small volcano to cover a large area to the west with a lava flow which remains largely free of vegetation. The lava flows reached the Deschutes River abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garibaldi Lake
Garibaldi Lake is a turquoise-coloured alpine lake in British Columbia, Canada, located 37 km (23 mi) north of Squamish and 19 km (12 mi) south of Whistler. The lake lies within Garibaldi Provincial Park, which features mountains, glaciers, trails, forests, flowers, meadows, waterfalls. The park is a wildlife protected area. Geology Garibaldi Lake lies in a deep subalpine basin, with its surface at nearly 1,500 m (4,900 ft) above sea level and a depth exceeding 250 m (800 ft). It is almost entirely surrounded by mountains except at its northwestern tip, with volcanoes along the north, west, and south sides and non-volcanic peaks along the northeast and eastern shores. Lava flows from the volcanoes of Mount Price and Clinker Peak to the south blocked the ancestral valley, damming the waters of the lake behind the lava formation known as The Barrier. This lava dam is over 300 m (1,000 ft) in thickness and about 2 km (1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Barrier
The Barrier is a lava dam retaining the Garibaldi Lake system in southwestern British Columbia, Canada. It is over thick and about long where it impounds the lake. The area below and adjacent to The Barrier is considered hazardous due to the unstable lava formation. Formation The Barrier was formed about 15,000–12,000 years ago when large lava flows emanated from Clinker Peak on the west shoulder of Mount Price. The large lava flowed towards the Cheakamus River valley. At the time of eruption, the valley was filled by glacial ice. The lava flow was stopped by the ice and ponded, eventually cooling to form an ice-marginal lava flow. When the ice melted away, the ice-cooled lava-flow front formed a precipitous cliff; water ponded behind the lava dam, forming Garibaldi Lake. Rubble Creek boulder field The unstable lava formation of The Barrier has in the past unleashed several debris flows in the area below Garibaldi Lake. The most recent major landslide in 1855-1856 fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Lake (Oregon)
Lava Lake lies in the Cascade Range about west-southwest of Bend in the U.S. state of Oregon. It is a close neighbor of Little Lava Lake, from which it is separated by solidified lava. Lava Lake is at an elevation of in the Deschutes National Forest. The lake covers to an average depth of . Lava Lake, Little Lava Lake, and other nearby lakes are volcanogenic, having formed after lava flows from Mount Bachelor altered drainage patterns in the area. Solidified lava flows are visible along the shorelines of both lakes, and the volcanic peaks Broken Top and South Sister can be seen to the north. Recreation Fish in the lake include rainbow trout that grow to and brook trout that sometimes reach . Controlled populations of tui chub also live in the lake. A United States Forest Service campground and a private resort are near the lake, and Little Lava Lake also has campsites. Amenities around the lake include parking areas, two boat ramps, and a fish cleaning station. Tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mývatn
() is a shallow lake situated in an area of active volcanism in the north of Iceland, not far from Krafla volcano. It has a high amount of biological activity. The lake and the surrounding wetlands provides a habitat for a number of waterbirds, especially ducks. The lake was created by a large basaltic lava eruption 2300 years ago, and the surrounding landscape is dominated by volcanic landforms, including lava pillars and rootless vents (pseudocraters). The effluent river is known for its rich fishing for brown trout and Atlantic salmon. The name of the lake ( Icelandic ("midge") and ("lake"); "the lake of midges") comes from the large numbers of midges present in the summer. The name is sometimes used not only for the lake but the whole surrounding inhabited area. The river , the lake and the surrounding wetlands are protected as a nature reserve (the – Nature Conservation Area, which occupies ). Since the year 2000, a marathon around the lake takes place in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caburgua Lake
Caburgua Lake () is located 23 km northeast of the city of Pucón, in the La Araucanía Region of Chile. Huerquehue National Park lies to the east of the lake. Like Villarrica Lake, it is part of Toltén River basin. During summer the outflow river may dry out but due to high levels of underground infiltration the waterfalls Ojos del Caburgua never run dry. The lake occupies a glacial valley carved out along the Liquiñe-Ofqui Fault. In the Holocene the valley was blocked by lava flows from the Volcanes de Caburgua. The lake has recently gained notoriety for the holiday residences of people like former Presidents Sebastián Piñera and Michelle Bachelet Verónica Michelle Bachelet Jeria (; born 29 September 1951) is a Chilean politician who served as United Nations High Commissioner for Human Rights from 2018 to 2022. She previously served as President of Chile from 2006 to 2010 and 2014 to 201 .... History The earliest Caburgua inhabitants before the Spanish were the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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