|
Aleutian Range
The Aleutian Range is a major mountain range located in southwest Alaska. It extends from Chakachamna Lake (80 miles/130 km southwest of Anchorage) to Unimak Island, which is at the tip of the Alaska Peninsula. It includes all of the mountains of the Peninsula. The Aleutian Range is special because of its large number of active volcanoes, which are also part of the larger Aleutian Arc. The mainland part of the range is about 600 miles (1000 km) long. The Aleutian Islands are (geologically) a partially submerged western extension of the range that stretches for another 1,600 km (1000 mi). However the official designation "Aleutian Range" includes only the mainland peaks and the peaks on Unimak Island. The range is almost entirely roadless wilderness. Katmai National Park and Preserve, a large national park within the range, must be reached by boat or plane. The core Aleutian Range can be divided into three mountain groups. Listed from southwest to northeast, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Redoubt (Alaska)
Redoubt Volcano, or Mount Redoubt ( Dena'ina: ''Bentuggezh K’enulgheli''), is an active stratovolcano in the largely volcanic Aleutian Range of the U.S. state of Alaska. Located at the head of the Chigmit Mountains subrange in Lake Clark National Park and Preserve, the mountain is just west of Cook Inlet, in the Kenai Peninsula Borough about 110 miles (180 km) southwest of Anchorage. At 10,197 feet (3,108 m), in just over 5 miles (8 km) Mount Redoubt attains 9,150 feet (2,700 m) of prominence over its surrounding terrain. It is the highest summit in the Aleutian Range. In 1976, Redoubt Volcano was designated as a National Natural Landmark by the National Park Service. Active for millennia, Mount Redoubt has erupted four times since it was first observed: in 1902, 1966, 1989 and 2009, with two questionable eruptions in 1881 and 1933. The eruption in 1989 spewed volcanic ash to a height of . It caught KLM Flight 867, a Boeing 747 aircraft, in its plume. Af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Shishaldin
Shishaldin Volcano, or Mount Shishaldin (), is a moderately active volcano on Unimak Island in the Aleutian Islands chain of Alaska in the United States.Alaska Volcano Observatory, Volcano Information -- Shishaldin Retrieved Dec. 16, 2022. It is the highest mountain peak of the Aleutian Islands. The volcano's topographic contour lines are nearly perfect circles above . The lower north and south slopes are somewhat steeper than the lower eastern and western slopes. The volcano is the westernmost of three large along an east–west line in the eastern half of Unimak Island. The upper is almost entirely covered by glacial snow and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Of Focus (tectonics)
In seismology, the depth of focus or focal depth refers to the depth at which an earthquake occurs. Earthquakes occurring at a depth of less than are classified as shallow-focus earthquakes, while those with a focal depth between and are commonly termed mid-focus or intermediate-depth earthquakes. In subduction zones, where older and colder oceanic crust sinks under another tectonic plate, deep-focus earthquakes may occur at much greater depths in the mantle, ranging from up to . The cause of deep-focus earthquakes is still not entirely understood since subducted lithosphere at that pressure and temperature regime should not exhibit brittle behavior. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure, with which they are believed to be associated. Earthquakes at this depth of focus typically occur at oceanic-continental convergent boundaries, along Wadati–Benioff zones. Discover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2014 Aleutian Islands Earthquake
The 2014 Aleutian Islands earthquake occurred on 23 June at 11:53 Hawaii–Aleutian Time Zone, HDT (UTC-9) with a Moment magnitude scale, moment magnitude of 7.9 and a maximum Mercalli intensity scale, Mercalli intensity of VIII (''Severe''). The shock occurred in the Aleutian Islands – part of the US state of Alaska – southeast of Little Sitkin Island. Earthquake The earthquake was initially reported as 8.0 before it was downgraded to 7.9. The rupture was on a normal fault, at ~107 km depth. Based on the geometry of the slab, and the relative movement of the tectonic plates, the slip vector is likely to have been oblique down-dip towards the ESE. The fault plane appears to be oblique, striking NW-SE and cutting steeply into the subducting slab. Tsunami A tsunami warning was issued, but was soon downgraded to a tsunami advisory for much of the Aleutian Islands; however, the hypocenter was too deep to generate a tsunami that would affect the Pacific Ocean, Pacific bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Magnitude Scale
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude scale, local magnitude/Richter scale () defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often says "Richter scale" when referring to the moment magnitude scale. Moment magnitude () is considered the authoritative magnitude scale for ranking earthquakes by size. It is more directly related to the energy of an earthquake than other scales, and does not saturate—that is, it does not underestimate magnitudes as other scales do in certain conditions. It has become the standard scale used by seismological authorities like the U.S. Geological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pogromni Volcano
Pogromni Volcano is a stratovolcano on Unimak Island in the Aleutian Islands. Near it are 5 cinder cones, and a mountain called Pogromni's Sister. Pogromni is old and eroded with a single glacier on its flank and base. Eruptions have been attributed to it in 1795, 1796, 1826, 1827, and 1830, but historic eruptions attributed to it may have come from nearby Westdahl Volcano.Alaska Volcano Observatory, Volcano Information -- Pogromni Retrieved Jan. 6, 2023. __TOC__ Etymology The volcano's name comes from the Russian "Погромный," meaning "characterized by violent outbreak." This naming refers to a volcanic eruption, but shares the same etymology as |
Mount Katmai
Mount Katmai (russian: Катмай) is a large stratovolcano (composite volcano) on the Alaska Peninsula in southern Alaska, located within Katmai National Park and Preserve. It is about in diameter with a central lake-filled caldera about in size, formed during the Novarupta eruption of 1912. The caldera rim reaches a maximum elevation of . In 1975 the surface of the crater lake was at an elevation of about , and the estimated elevation of the caldera floor is about . The mountain is located in Kodiak Island Borough, very close to its border with Lake and Peninsula Borough. Geology Mount Katmai is one of five vents encircling the Novarupta volcano, source of the VEI 6 eruption and associated voluminous pyroclastic flows in 1912. The volcano has caused ten known fatalities due to gas exposure. Katmai consists chiefly of lava flows, pyroclastic rocks, and non-welded to agglutinated air fall. The Quaternary volcanic rocks at Katmai and adjacent cones are less than thick. Muc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Peak (Alaska)
Double Peak is a prominent 6,818 foot (2,078 meter) mountain summit located in Lake Clark National Park and Preserve, in the Chigmit Mountains of the Aleutian Range, in the US state of Alaska. It is the highest non-volcanic peak in the Chigmit Mountains, and third-highest overall. The mountain is situated immediately north of Double Glacier, west-southwest of Anchorage, and north-northeast of Redoubt Volcano, which is the nearest higher peak. Although modest in elevation, relief is significant since the mountain rises up from tidewater at Cook Inlet in about 20 miles, and it ranks 71st in prominence for all peaks in Alaska. Double Peak was considered to be a volcano by the International Association of Volcanology and Chemistry of the Earth's Interior in 1973, but subsequent reconnaissance mapping indicates the peak is likely made of plutonic rocks of Jurassic age. Published in 1912 by the United States Coast and Geodetic Survey, the mountain takes its name from the Double Glac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Chiginagak
Chiginagak Volcano is a stratovolcano on the Alaska Peninsula, located about 15 km NW of Chiginagak Bay. Eruptive history An unglaciated lava flow and an overlying pyroclastic-flow deposit extending east from the summit are the most recent products of Chiginagak. They most likely originated from a lava dome at 1687m on the SE flank, 1 km from the summit of the volcano. Brief ash eruptions were reported in July 1971 and August 1998. Fumarolic activity occurs at 1600m elevation on the NE flank of the volcano, and two areas of hot-spring travertine deposition are located at the NW base of the volcano near Volcano Creek. A wide and deep acidified summit crater lake at Chiginagak formed after November 2004 and before May 2005. In early May 2005, a catastrophic release of acidic water from the lake, with an accompanying acidic aerosol component, drained and flooded indecision and volcano creeks with acidic water, traveled 27 km downstream and flowed into the Mother Go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Douglas (Alaska)
Mount Douglas is a stratovolcano located south of Kamishak Bay, near the northeasternmost part of the Alaska Peninsula. It lies in the Katmai National Park and Preserve in Kenai Peninsula Borough. The mountain was officially named in 1906 after nearby Cape Douglas based on a 1904 report by USGS geologist G. C. Martin. The Alaska Volcano Observatory currently rates Douglas as Level of Concern Color Code Not Assigned. The volcano has a warm and highly acidic crater lake approximately 160 m (525 ft) wide. In 1982, the lake had a temperature of 21 °C and a pH of 1, and temperatures of 114-118°C were measured in 1991. At the north flank of the volcano unglaciated and relatively uneroded lava flows are found. The last eruption is not known, but probably occurred during the Holocene. __TOC__ See also *List of mountain peaks of North America **List of mountain peaks of the United States ***List of mountain peaks of Alaska *List of Ultras of the United States *List o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Griggs
Mount Griggs, formerly known as Knife Peak Volcano, is a stratovolcano, which lies 10 km behind the volcanic arc defined by other Katmai group volcanoes. Although no historic eruptions have been reported from Mount Griggs, vigorously active fumaroles persist in a summit crater and along the upper southwest flank. The fumaroles on the southwest flank are the hottest, and some of the flank fumaroles can roar so loudly that they can be heard from the valley floor. The slopes of Mount Griggs are heavily mantled by fallout from the 1912 eruption of Novarupta volcano. The summit consists of three concentric craters, the lowest and largest of which contains a recent summit cone topped by two craters. The volume of the volcanic edifice is estimated at about . Isotopic analysis indicates that the source of Griggs' magma is distinct from the other Katmai volcanoes. The mountain was named for Dr. Robert Fiske Griggs (1881–1962), botanist, whose explorations of the area, after the er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Denison
Mount Denison is a stratovolcano and one of the highest peaks on the Alaska Peninsula. Discovered in 1923 by Harvard professor Kirtley Fletcher Mather, the mountain was named for the geologist's alma mater, Denison University. The mountain's connection to Denison also include its first climbers: all members of the first two ascent teams as well as the group that attempted in 1977 were either students, alumni, or faculty of the university. Mount Denison is located at the end of a volcanic chain in a heavily glaciated and very remote section of Katmai National Park. It is possibly the tallest mountain in the national park, though some sources list Mount Griggs as the highest. Mount Griggs, on the other hand, is much more accessible, being next to the Valley of Ten Thousand Smokes, which can be reached via the road from the national park's visitor center. There is no record of an eruption, but Mount Denison was probably active some time in the last 10,000 years (the Holocene epoch) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
