Mount Erebus, 2014
|Elevation||3,794 m (12,448 ft)|
|Prominence||3,794 m (12,448 ft) |
|Isolation||121 kilometres (75 mi)|
|Location|| Ross Island, Antarctica |
(claimed by New Zealand as part of the Ross Dependency)
|Topo map||Ross Island|
|Age of rock||1.3 million years|
|Mountain type||Stratovolcano (composite cone)|
|Last eruption||1972 to present|
|First ascent||1908 by Edgeworth David and party|
|Easiest route||Basic snow & ice climb|
Mount Erebus ( // ) is the second-highest volcano in Antarctica (after Mount Sidley) and the southernmost active volcano on Earth. It is the sixth-highest ultra mountain on the continent. With a summit elevation of 3,794 metres (12,448 ft), it is located in the Ross Dependency on Ross Island, which is also home to three inactive volcanoes: Mount Terror, Mount Bird, and Mount Terra Nova.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Antarctica is Earth's southernmost continent. It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,200,000 square kilometres, it is the fifth-largest continent and nearly twice the size of Australia. At 0.00008 people per square kilometre, it is by far the least densely populated continent. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, which extends to all but the northernmost reaches of the Antarctic Peninsula.
Mount Sidley is the highest dormant volcano in Antarctica, a member of the Volcanic Seven Summits, with a summit elevation of 4,181–4,285 metres (13,717–14,058 ft). It is a massive, mainly snow-covered shield volcano which is the highest of the five volcanic mountains that comprise the Executive Committee Range of Marie Byrd Land. The feature is marked by a 5 km wide caldera on the southern side and stands NE of Mount Waesche in the southern part of the range.
The volcano has been active since about 1.3 million years agoand is the site of the Mount Erebus Volcano Observatory run by the New Mexico Institute of Mining and Technology.
The New Mexico Institute of Mining and Technology is a public university in Socorro, New Mexico.
The volcano was the site of the Air New Zealand Flight 901 accident, which occurred in November 1979.
Air New Zealand Flight 901 (TE-901) was a scheduled Air New Zealand Antarctic sightseeing flight that operated between 1977 and 1979. The flight would leave Auckland Airport in the morning and spend a few hours flying over the Antarctic continent, before returning to Auckland in the evening via Christchurch. On 28 November 1979, the fourteenth flight of TE-901, a McDonnell Douglas DC-10-30, registration ZK-NZP, flew into Mount Erebus on Ross Island, Antarctica, killing all 237 passengers and 20 crew on board. The accident became known as the Mount Erebus disaster.
Mount Erebus is currently the most active volcano in Antarctica and is the current eruptive zone of the Erebus hotspot. The summit contains a persistent convecting phonolitic lava lake, one of five long-lasting lava lakes on Earth. Characteristic eruptive activity consists of Strombolian eruptions from the lava lake or from one of several subsidiary vents, all within the volcano's inner crater.The volcano is scientifically remarkable in that its relatively low-level and unusually persistent eruptive activity enables long-term volcanological study of a Strombolian eruptive system very close (hundreds of metres) to the active vents, a characteristic shared with only a few volcanoes on Earth, such as Stromboli in Italy. Scientific study of the volcano is also facilitated by its proximity to McMurdo Station (U.S.) and Scott Base (New Zealand), both sited on Ross Island around 35 km away.
The Erebus hotspot is a volcanic hotspot responsible for the high volcanic activity on Ross Island in the western Ross Sea of Antarctica. Its current eruptive zone, Mount Erebus, has erupted continuously since its discovery in 1841.
Phonolite is an uncommon extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grain) to porphyritic. Its intrusive equivalent is nepheline syenite.
Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified.
Mount Erebus is classified as a polygenetic stratovolcano. The bottom half of the volcano is a shield and the top half is a stratocone. The composition of the current eruptive products of Erebus are anorthoclase-porphyritic tephritic phonolite and phonolite, which are the bulk of exposed lava flow on the volcano. The oldest eruptive products consist of relatively undifferentiated and nonviscous basanite lavas that form the low broad platform shield of Erebus. Slightly younger basanite and phonotephrite lavas crop out on Fang Ridge—an eroded remnant of an early Erebus volcano—and at other isolated locations on the flanks of Erebus. Erebus is the world's only presently erupting phonolite volcano.
A polygenetic volcanic field is a group of polygenetic volcanoes, each of which erupts repeatedly, in contrast with monogenetic volcanoes, each of which erupts only once. Polygenetic volcanic fields generally occur where there is a high-level magma chamber. These volcanic fields may show lithological discontinuities due to major changes in magma chemistry, volcanotectonic events, or long erosional intervals, and may last over 10 million years.
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava, tephra, pumice and ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica, with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as 15 km (9.3 mi).
The mineral anorthoclase ((Na,K)AlSi3O8) is a crystalline solid solution in the alkali feldspar series, in which the sodium-aluminium silicate member exists in larger proportion. It typically consists of between 10 and 36 percent of KAlSi3O8 and between 64 and 90 percent of NaAlSi3O8.
Lava flows of more viscous phonotephrite and trachyte erupted after the basanite. The upper slopes of Mount Erebus are dominated by steeply dipping (about 30°) tephritic phonolite lava flows with large-scale flow levees. A conspicuous break in slope around 3,200 m ASL calls attention to a summit plateau representing a caldera. The summit caldera was created by an explosive VEI-6 eruption that occurred 18,000 ± 7,000 years ago.It is filled with small volume tephritic phonolite and phonolite lava flows. In the center of the summit caldera is a small, steep-sided cone composed primarily of decomposed lava bombs and a large deposit of anorthoclase crystals known as Erebus crystals. The active lava lake in this summit cone undergoes continuous degassing.
Trachyte is an igneous volcanic rock with an aphanitic to porphyritic texture. It is the volcanic equivalent of syenite. The mineral assemblage consists of essential alkali feldspar; relatively minor plagioclase and quartz or a feldspathoid such as nepheline may also be present.. Biotite, clinopyroxene and olivine are common accessory minerals.
Strike and dip refer to the orientation or attitude of a geologic feature. The strike line of a bed, fault, or other planar feature, is a line representing the intersection of that feature with a horizontal plane. On a geologic map, this is represented with a short straight line segment oriented parallel to the strike line. Strike can be given as either a quadrant compass bearing of the strike line or in terms of east or west of true north or south, a single three digit number representing the azimuth, where the lower number is usually given, or the azimuth number followed by the degree sign.
A caldera is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber/reservoir in a volcanic eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is lost. The ground surface then collapses downward into the emptied or partially emptied magma chamber, leaving a massive depression at the surface. Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Only seven caldera-forming collapses are known to have occurred since 1900, most recently at Bárðarbunga volcano, Iceland in 2014.
Researchers spent more than three months during the 2007–08 field season installing an atypically dense array of seismometers around Mount Erebus to listen to waves of energy generated by small, controlled blasts from explosives they buried along its flanks and perimeter, and to record scattered seismic signals generated by lava lake eruptions and local ice quakes. By studying the refracted and scattered seismic waves, the scientists produced an image of the uppermost (top few km) of the volcano to understand the geometry of its "plumbing" and how the magma rises to the lava lake.These results demonstrated a complex upper-volcano conduit system with appreciable upper-volcano magma storage to the northwest of the lava lake at depths hundreds of meters below the surface.
Mt. Erebus is notable for its numerous ice fumaroles – ice towers that form around gases that escape from vents in the surface.The ice caves associated with the fumaroles are dark, in polar alpine environments starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. The life is sparse, mainly bacteria and fungi. This makes it of special interest for studying oligotrophs – organisms that can survive on minimal amounts of resources.
The caves on Erebus are of special interest for astrobiology,as most surface caves are influenced by human activities, or by organics from the surface brought in by animals (e.g. bats) or ground water. The caves at Erebus are at high altitude, yet accessible for study. Almost no chance exists of photosynthetic-based organics, or of animals in a food chain based on photosynthetic life, and no overlying soil to wash down into them.
They are dynamic systems that collapse and rebuild, but persist over decades. The air inside the caves has 80 to 100% humidity, and up to 3% carbon dioxide (CO2), and some carbon monoxide (CO) and hydrogen (H2), but almost no methane (CH4) or hydrogen sulfide (H2S). Many of them are completely dark, so cannot support photosynthesis. Organics can only come from the atmosphere, or from ice algae that grow on the surface in summer, which may eventually find their way into the caves through burial and melting. As a result, most micro-organisms there are chemolithoautotrophic i.e. microbes that get all of their energy from chemical reactions with the rocks, and that do not depend on any other lifeforms to survive. The organisms survive using CO2 fixation and some may use CO oxidization for the metabolism. The main types of microbe found there are Chloroflexi and Acidobacteria.
Mount Erebus is large enough to have several named features on its slopes, including a number of craters and rock formations.
Named craters located on Mount Erebus include Side Crater, a nearly circular crater named for its location on the side of the main summit cone, and Western Crater, named for the slope on which it sits.
There are many rock formations on Mount Erebus. On the northwest upper slope of the active cone near a former exploration camp site, lava flow has formed a prominent outcropping called Nausea Knob, named for the nausea caused by elevation sickness.Also on the northwest slope sits Tarr Nunatak, named by the New Zealand Geographic Board (NZGB) in 2000 after Sgt. L.W. Tarr, an aircraft mechanic with the New Zealand contingent of the Commonwealth Trans-Antarctic Expedition. On the southwest rim of the summit caldera sits Seismic Bluff, named for a seismic station nearby.
Mount Erebus was discovered on January 27, 1841 (and observed to be in eruption),by polar explorer Sir James Clark Ross, who named it and its companion, Mount Terror, after his ships, Erebus and Terror (which were later used by Sir John Franklin on his disastrous Arctic expedition). Present with Ross on the Erebus was the young Joseph Hooker, future president of the Royal Society and close friend of Charles Darwin. Erebus is a dark region in Hades in Greek mythology, personified as the Ancient Greek primordial deity of darkness, the son of Chaos.
The mountain was surveyed in December 1912 by a science party from Robert Falcon Scott's Terra Nova expedition, who also collected geological samples. Two of the camp sites they used have been recognised for their historic significance:
They have been designated historic sites or monuments following a proposal by the United Kingdom, New Zealand, and the United States to the Antarctic Treaty Consultative Meeting.
Mount Erebus' summit crater rim was first achieved by members of Sir Ernest Shackleton's party; Professor Edgeworth David, Sir Douglas Mawson, Dr Alister Mackay, Jameson Adams, Dr Eric Marshall and Phillip Brocklehurst (who did not reach the summit), in 1908. Its first known solo ascent and the first winter ascent was accomplished by British mountaineer Roger Mear on 7 June 1985, a member of the "In the Footsteps of Scott" expedition.On January 19–20, 1991, Charles J. Blackmer, an iron-worker for many years at McMurdo Station and the South Pole, accomplished a solo ascent in about 17 hours completely unassisted, by snow mobile and on foot.
In 1992, the inside of the volcano was explored by Dante I, an eight legged tethered robotic explorer.Dante was designed to acquire gas samples from the magma lake inside the inner crater of Mount Erebus to understand the chemistry better through the use of the on-board gas chromatograph, as well as measuring the temperature inside the volcano and the radioactivity of the materials present in such volcanoes. Dante successfully scaled a significant portion of the crater before technical difficulties emerged with the fibre-optic cable used for communications between the walker and base station. Unfortunately, Dante I had not yet reached the bottom of the crater, so no data of volcanic significance was recorded. However, the expedition proved to be highly successful in terms of robotic and computer science, and was possibly the first expedition by a robotic platform to Antarctica.
Air New Zealand Flight 901 was a scheduled sightseeing service from Auckland Airport in New Zealand to Antarctica and return with a scheduled stop at Christchurch Airport to refuel before returning to Auckland. 13 miles (21 km) to the left and 10 miles (16 km) to the right of the aircraft visible. Further investigation of the crash showed an Air New Zealand navigational error and a cover-up that resulted in about $100 million in lawsuits. Air New Zealand discontinued its flyovers of Antarctica. Its final flight was on February 17, 1980. During the Antarctic summer, snow melt on the flanks of Mount Erebus continually reveals debris from the crash; it is visible from the air.The Air New Zealand flyover service, for the purposes of Antarctic sightseeing, was operated with McDonnell Douglas DC-10-30 aircraft and began in February 1977. The flight crashed into Mount Erebus on November 28, 1979, killing all 257 people on board. Passenger photographs taken seconds before the collision removed all doubt of whiteout conditions or the "flying in a cloud" theory, showing perfectly clear visibility well beneath the cloud base, with landmarks
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 50 miles (80 km) northeast of Portland, Oregon and 96 miles (154 km) south of Seattle, Washington. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century. The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows.
Ross Island is an island formed by four volcanoes in the Ross Sea near the continent of Antarctica, off the coast of Victoria Land in McMurdo Sound. Ross Island lies within the boundaries of Ross Dependency, an area of Antarctica claimed by New Zealand.
The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur. In a large 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and plate movements. It has 452 volcanoes.
Mount Terror is a large shield volcano that forms the eastern part of Ross Island, Antarctica. It has numerous cinder cones and domes on the flanks of the shield and is mostly under snow and ice. It is the second largest of the four volcanoes which make up Ross Island and is somewhat overshadowed by its neighbor, Mount Erebus, 30 km (19 mi) to the west. Mt. Terror was named in 1841 by Sir James Clark Ross for his second ship, HMS Terror. The captain of Terror was Captain Francis Crozier who was a close friend of Ross.
Mount Thielsen, or Big Cowhorn, is an extinct shield volcano in the Oregon High Cascades, near Mount Bailey. Because eruptive activity ceased 250,000 years ago, glaciers have heavily eroded the volcano's structure, creating precipitous slopes and a horn-like peak. The spire-like shape of Thielsen attracts lightning strikes and creates fulgurite, an unusual mineral. The prominent horn forms a centerpiece for the Mount Thielsen Wilderness, a reserve for recreational activities such as skiing and hiking.
Mount Mazama is a complex volcano in the state of Oregon, United States, in a segment of the Cascade Volcanic Arc and Cascade Range that was partially destroyed when it erupted about 7,700 years ago. The volcano is in Klamath County, in the southern Cascades, 60 miles (97 km) north of the Oregon-California border. Its collapse formed a caldera that holds Crater Lake. The mountain is in Crater Lake National Park. Mount Mazama originally had an elevation of 12,000 feet (3,700 m), but following its climactic eruption this was reduced to 8,157 feet (2,486 m). Crater Lake is 1,943 feet (592 m) deep, the deepest freshwater body in the US and the second deepest in North America after Great Slave Lake in Canada.
Mount Katmai is a large stratovolcano on the Alaska Peninsula in southern Alaska, located within Katmai National Park and Preserve. It is about 6.3 miles (10 km) in diameter with a central lake-filled caldera about two by three miles in size, formed during the Novarupta eruption of 1912. The caldera rim reaches a maximum elevation of 6,716 feet (2,047 m). In 1975 the surface of the crater lake was at an elevation of about 4,220 feet (1,286 m), and the estimated elevation of the caldera floor is about 3,400 ft (1,040 m). The mountain is located in Kodiak Island Borough, very close to its border with Lake and Peninsula Borough.
Mount Spurr is a stratovolcano in the Aleutian Arc of Alaska, named after United States Geological Survey geologist and explorer Josiah Edward Spurr, who led an expedition to the area in 1898. The Alaska Volcano Observatory (AVO) currently rates Mount Spurr as Level of Concern Color Code Green. The mountain is known aboriginally by the Dena'ina Athabascan name K'idazq'eni, literally 'that which is burning inside'.
Piton de la Fournaise is a shield volcano on the eastern side of Réunion island in the Indian Ocean. It is currently one of the most active volcanoes in the world, along with Kīlauea in the Hawaiian Islands, Stromboli and Etna in Italy and Mount Erebus in Antarctica. A previous eruption began in August 2006 and ended in January 2007. The volcano erupted again in February 2007, on 21 September 2008, on 9 December 2010, which lasted for two days, and on 1 August 2015. The most recent eruption began on 11 August 2019. The volcano is located within Réunion National Park, a World Heritage site.
Mount Berlin is the sixth highest volcano in Antarctica, located 16 km west of Mount Moulton in Marie Byrd Land near the eastern coast of the Ross Sea. It is composed of two coalesced shield volcanoes: Merrem Peak and Berlin Crater. The volcanic structure is considered active, as steaming fumaroles have been observed near the rim of the northern and western calderas, producing fumarolic ice towers.
Mount Moulton is a 40-kilometre-long (25 mi) complex of ice-covered shield volcanoes, standing 25 kilometres (16 mi) east of Mount Berlin in the Flood Range, Marie Byrd Land, Antarctica. It is named for Richard S. Moulton, chief dog driver at West Base. The volcano is of Pliocene age and is presently inactive.
A volcanogenic lake is a lake formed as a result of volcanic activity. They are generally a body of water inside an inactive volcanic crater but can also be large volumes of molten lava within an active volcanic crater and waterbodies constrained by lava flows, pyroclastic flows or lahars in valley systems. The term volcanic lake is also used to describe volcanogenic lakes, although it is more commonly assigned to those which host a vent.
A subglacial volcano, also known as a glaciovolcano, is a volcanic form produced by subglacial eruptions or eruptions beneath the surface of a glacier or ice sheet which is then melted into a lake by the rising lava. Today they are most common in Iceland and Antarctica; older formations of this type are found also in British Columbia and Yukon Territory, Canada.
Mount Siple is a potentially active Antarctic shield volcano, rising to 3,110 metres (10,203 ft) and dominating the northwest part of Siple Island, which is separated from the Bakutis Coast, Marie Byrd Land, by the Getz Ice Shelf. Its youthful appearance strongly suggests that it last erupted in the Holocene. It is capped by a 4-by-5-kilometre summit caldera, and tuff cones lie on the lower flanks. Recely Bluff is on the northeast slope of the mountain, about 7 nautical miles (13 km) from the peak. Its volume of 1,800 cubic kilometres (430 cu mi) is comparable to that of Mount Erebus.
Cockburn Island is an oval island 2.7 kilometres (1.7 mi) long, consisting of a high plateau with steep slopes surmounted on the northwest side by a pyramidal peak 450 m (1,476 ft) high, lying in the north-east entrance to Admiralty Sound, south of the north-east end of the Antarctic Peninsula. It was discovered by a British expedition (1839-43) led by Captain James Clark Ross, who named it for Admiral Sir George Cockburn, then serving as First Naval Lord.
Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.
Mount Haddington is a massive 1,630 m (5,350 ft) high shield volcano comprising much of James Ross Island in Graham Land, Antarctica. It is 60 km (37 mi) wide and has had numerous subglacial eruptions throughout its history, forming many tuyas. Some of its single eruptions were bigger in volume than a whole normal-sized volcano. Old eruption shorelines are widespread on the volcano's deeply eroded flanks.
The Mount Edziza volcanic complex is a large and potentially active north-south trending complex volcano in Stikine Country, northwestern British Columbia, Canada, located 38 kilometres (24 mi) southeast of the small community of Telegraph Creek. It occupies the southeastern portion of the Tahltan Highland, an upland area of plateau and lower mountain ranges, lying east of the Boundary Ranges and south of the Inklin River, which is the east fork of the Taku River. As a volcanic complex, it consists of many types of volcanoes, including shield volcanoes, calderas, lava domes, stratovolcanoes, and cinder cones.
|Wikimedia Commons has media related to Mount Erebus .|