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Mount Katmai
Mount Katmai () is a large active 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. The volcano has caused ten known fatalities due to gas exposure. 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. 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. Much of the v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katmai National Park And Preserve
Katmai National Park and Preserve is a List of national parks of the United States, United States national park and National preserve, preserve in southwest Alaska, notable for the Valley of Ten Thousand Smokes and for its Alaska Peninsula brown bear, brown bears. The park and preserve encompass , which is between the sizes of Connecticut and New Jersey. Most of the national park is a designated wilderness area. The park is named after Mount Katmai, its centerpiece stratovolcano. The park is located on the Alaska Peninsula, across from Kodiak Island, with headquarters in nearby King Salmon, Alaska, King Salmon, about southwest of Anchorage, Alaska, Anchorage. The area was first designated a National monument (United States), national monument in 1918 to protect the area around the major 1912 volcanic eruption of Novarupta, which formed the Valley of Ten Thousand Smokes, a , pyroclastic flow. The park includes as many as 18 individual volcanoes, seven of which have been active si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciers
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land“Glacier, N., Pronunciation.” Oxford English Dictionary, Oxford UP, June 2024, https://doi.org/10.1093/OED/7553486115. Accessed 25 Jan. 2025. and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mud Pot
A mudpot, or mud pool, is a type of acidic hot spring, or fumarole, with limited water. It usually takes the form of a pool of bubbling mud, as a result of the acid and microorganisms decomposing surrounding rock into clay and mud. Description The mud of a mudpot takes the form of a viscous, often bubbling, slurry. As the boiling mud is often squirted over the brims of the mudpot, a form resembling a mini-volcano of mud starts to build up, sometimes reaching heights of . Although mudpots are often called "mud volcanoes", true mud volcanoes are very different in nature. The mud of a mudpot is generally of white to greyish color, but is sometimes stained with reddish or pink spots from iron compounds. When the slurry is particularly colorful, the feature may be referred to as a paint pot. Geology Mudpots form in high-temperature geothermal areas where water supply is short. The little water that is available rises to the surface at a spot where the soil is rich in volcanic ash, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valley Of Ten Thousand Smokes
The Valley of Ten Thousand Smokes is a valley within Katmai National Park and Preserve in Alaska which is filled with ash flow from the eruption of Novarupta on June 6–8, 1912. Following the eruption, thousands of fumaroles vented steam from the ash. Robert F. Griggs, who explored the volcano's aftermath for the National Geographic Society in 1916, gave the valley its name, saying that "the whole valley as far as the eye could reach was full of hundreds, no thousands—literally, tens of thousands—of smokes curling up from its fissured floor." Prior to the eruption, the area now called the Valley of Ten Thousand Smokes was an unremarkable and unnamed portion of the Ukak River valley. Although never permanently inhabited by humans, it served as a pass for the Alutiiq people, as well as animals such as grizzly bears. The 1912 eruption was the largest eruption by volume in the 20th century, erupting a magma volume of about . As many as 14 major earthquakes between M_\tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumarole
A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcanic activity, but fumarole activity can also precede a volcanic eruption and has been used for eruption prediction. Most fumaroles die down within a few days or weeks of the end of an eruption, but a few are persistent, lasting for decades or longer. An area containing fumaroles is known as a fumarole field. The predominant vapor emitted by fumaroles is steam, formed by the circulation of groundwater through heated rock. This is typically accompanied by volcanic gases given off by magma cooling deep below the surface. These volcanic gases include sulfur compounds, such as various sulfur oxides and hydrogen sulfide, and sometimes hydrogen chloride, hydrogen fluoride, and other gases. A fumarole that emits significant sulfur compounds is some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatic Eruption
A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from ) causes near-instantaneous evaporation of water to steam, resulting in an explosion of steam, water, ash, rock, and volcanic bombs. At Mount St. Helens in Washington state, hundreds of steam explosions preceded the 1980 Plinian eruption of the volcano. A less intense geothermal event may result in a mud volcano. Phreatic eruptions typically include steam and rock fragments; the inclusion of liquid lava is unusual. The temperature of the fragments can range from cold to incandescent. If molten magma is included, volcanologists classify the event as a phreatomagmatic eruption. These eruptions occasionally create broad, low-relief craters called '' maars''. Phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas-emissions. Carbon diox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Dome
In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth form lava domes. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day). The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite. Existence of lava domes has been suggested for some domed structures on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz. Dacite is relatively common, occurring in many tectonic settings. It is associated with andesite and rhyolite as part of the subalkaline tholeiitic and calc-alkaline magma series. Etymology The word ''dacite'' comes from Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains (now modern Romania and Moldova) where the rock was first described. The term ''dacite'' was used for the first time in the scientific literature in the book ''Geologie Siebenbürgens'' (''The Geology of Transylvania'') by Austrian geologists Franz Ritter von Hauer and Guido Stache. Dacite was originally defined as a new rock type to separate calc-alkaline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and volcanic gas, gas bubbles. Magma is produced by melting of the mantle (geology), mantle or the Crust (geology), crust in various tectonics, tectonic settings, which on Earth include subduction zones, continental rift (geology), rift zones, mid-ocean ridges and Hotspot (geology), hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal mush, crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by Fractional crystallization (geology), fractional crystallization, contaminati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revenue Cutter
A cutter is any of various types of watercraft. The term can refer to the rig (sail plan) of a sailing vessel (but with regional differences in definition), to a governmental enforcement agency vessel (such as a coast guard or border force cutter), to a type of ship's boat which can be used under sail or oars, or, historically, to a type of fast-sailing vessel introduced in the 18th century, some of which were used as small warships. As a sailing rig, a cutter is a single-masted boat, with two or more headsails. On the eastern side of the Atlantic, the two headsails on a single mast is the fullest extent of the modern definition. In U.S. waters, a greater level of complexity applies, with the placement of the mast and the rigging details of the bowsprit taken into account so a boat with two headsails may be classed as a sloop. Government agencies use the term "cutter" for vessels employed in patrolling their territorial waters and other enforcement activities. This terminol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Revenue Cutter Service
The United States Revenue Cutter Service was established by an Act of Congress () on 4 August 1790 as the Revenue-Marine at the recommendation of the nation's first U.S. Secretary of the Treasury, Alexander Hamilton. The federal government body was initially created to serve as an armed customs enforcement service. Over time, however, the service gradually gained missions either voluntarily or by legislation, including those of a military nature. It was generally referred to as the Revenue-Marine until 31 July 1894, when it was officially renamed the Revenue Cutter Service. The Revenue Cutter Service operated under the authority of the U.S. Department of the Treasury. On 28 January 1915, the service was merged by an act of Congress with the United States Life-Saving Service to form the United States Coast Guard. Background Immediately after the American Revolutionary War, the newly-established United States struggled financially. The federal government desperately needed reve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kodiak, Alaska
Kodiak (Alutiiq language, Alutiiq: ) is the main city and one of seven communities on Kodiak Island in Kodiak Island Borough, Alaska, Kodiak Island Borough, Alaska. All commercial transportation between the island's communities and the outside world goes through this city via ferryboat or airline. As of the 2020 United States census, 2020 census, the population of the city is 5,581, down from 6,130 in 2010. It is the List of cities in Alaska, tenth-largest city in Alaska. Inhabited by Alutiiq natives for over 7,000 years, Kodiak was settled in 1792 by subjects of the Imperial Russia, Russian crown. Originally named Paul's Harbor, it was the capital of Russian Alaska. Russian harvesting of the area's sea otter pelts led to the near extinction of the animal in the following century and led to wars with and enslavement of the natives for over 150 years. The city has experienced two natural disasters in the 20th century: a volcanic ashfall from the Novarupta#Eruption of 1912, 1912 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
