Mauna Loa
Mauna Loa from Saddle Road
Elevation	13,679 feet (4,169 m)
Location	Hawaii, USA
Range	Hawaiian Islands
Prominence	7,100 ft (2,160 m) [1]
Coordinates	19°28′46.3″N 155°36′09.6″W / 19.479528, -155.602667Coordinates: 19°28′46.3″N 155°36′09.6″W / 19.479528, -155.602667
Topo map	USGS Mauna Loa
Type	Shield volcano
Volcanic arc/belt	Hawaiian-Emperor seamount chain
Age of rock	less than 200 thousand years
Last eruption	1984
Easiest route	jeep trail

Mauna Loa map

Mauna Loa is the largest volcano on earth and one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean. In topography a summit is a point on a surface which is higher in Elevation than all points immediately adjacent to The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the The United States of America —commonly referred to as the A mountain range is a chain of Mountains bordered by highlands or separated from other mountains by passes or valleys The Hawaiian Islands, once known as the Sandwich Islands, form an Archipelago of 19 Islands and Atolls numerous smaller A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system. A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system. A topographic map is a type of Map characterized by large-scale detail and quantitative representation of relief, usually using Contour lines in modern The United States Geological Survey ( USGS) is a scientific agency of the United States government. Mountains can be characterized in several ways Some mountains are Volcanoes and can be characterized by the type of lava and eruptive history A shield volcano is a large Volcano with shallow-sloping sides A volcanic arc is a chain of volcanic islands or Mountains formed by Plate tectonics as an oceanic Tectonic plate subducts under A volcanic belt is a large volcanically active region Other terms are used for smaller areas of activity such as volcanic fields Volcanic belts are found above zones The Hawaiian-Emperor seamount chain is composed of the Hawaiian Ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor The geologic time scale is a chronologic schema (or idealized Model) relating Stratigraphy to time that is used by Geologists and other Plate tectonics and hotspots Divergent plate boundaries At the A climbing route is a path by which a climber reaches the top of a Mountain, rock or ice wall A trail is a Path or Road used for Walking, Cycling, Cross-country skiing, or other activities The Island of Hawaii, also called the Big Island or Hawaii Island, is a volcanic Island in the U A US state is any one of the fifty subnational entities of the United States of America that share Sovereignty with the federal government The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the The Pacific Ocean is the largest of the Earth 's Oceanic divisions It is an active shield volcano, with a volume estimated at approximately 18,000 cubic miles (75,000 km³),^[2] although its peak is about 120 feet (37 m) lower than that of its neighbor, Mauna Kea. Plate tectonics and hotspots Divergent plate boundaries At the A shield volcano is a large Volcano with shallow-sloping sides A cubic mile is an Imperial / US customary (non- SI non- metric) unit of Volume, used in the United States. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. Mauna Kea is a Dormant volcano in the Hawaiian Islands, one of five volcanoes which together form the Island of Hawaii. The Hawaiian name "Mauna Loa" means "Long Mountain". Lava eruptions from it are silica-poor, thus very fluid: and as a result eruptions tend to be non-explosive and the volcano has extremely shallow slopes. The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide A Hawaiian eruption is a type of Volcanic eruption where Lava flows from the vent in a relative gentle low level eruption so called because it is characteristic

The volcano has probably been erupting for at least 700,000 years and may have emerged above sea level about 400,000 years ago, although the oldest-known dated rocks do not extend beyond 200,000 years. ^[3] Its magma comes from the Hawaii hotspot, which has been responsible for the creation of the Hawaiian island chain for tens of millions of years. Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet The Hawaii hotspot is perhaps the best known volcanic hotspot on Earth, responsible for the Hawaiian Islands in the Pacific Ocean. The Hawaiian Islands, once known as the Sandwich Islands, form an Archipelago of 19 Islands and Atolls numerous smaller The slow drift of the Pacific Plate will eventually carry the volcano away from the hotspot, and the volcano will thus become extinct within 500,000 to one million years from now. The Pacific Plate is an oceanic Tectonic plate beneath the Pacific Ocean.

Mauna Loa's most recent eruption occurred from March 24, 1984, to April 15, 1984. Events 1401 - Mongol emperor Timur sacks Damascus. 1603 - James VI of Scotland Year 1984 ( MCMLXXXIV) was a Leap year starting on Sunday (link displays the 1984 Gregorian calendar) Events 1450 - Battle of Formigny: Toward the end of the Hundred Years' War, the French attack and nearly annihilate English Year 1984 ( MCMLXXXIV) was a Leap year starting on Sunday (link displays the 1984 Gregorian calendar) No recent eruptions of the volcano have caused fatalities, but eruptions in 1926 and 1950 destroyed villages, and the city of Hilo is partly built on lava flows from the late nineteenth century. Hilo (ˈhiːlo is a coastal town in the State of Hawai{{okina}}i. In view of the hazards it poses to population centers, Mauna Loa is part of the Decade Volcanoes program, which encourages studies of the most dangerous volcanoes. The Decade Volcanoes are 16 Volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI as being worthy Mauna Loa has been intensively monitored by the Hawaiian Volcano Observatory (HVO) since 1912. The Hawaiian Volcano Observatory is the Volcano observatory in Hawai&lsquoi that monitors the four active Hawaiian volcanoes Kīlauea, Mauna Observations of the atmosphere are undertaken at the Mauna Loa Observatory, and of the Sun at the Mauna Loa Solar Observatory, both located near its summit. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " The Mauna Loa Observatory (MLO is an atmospheric baseline station on Mauna Loa volcano, on the big island of Hawaii. The Sun (Sol is the Star at the center of the Solar System. The Mauna Loa Solar Observatory (MLSO is a collection of Solar imaging instruments located on the island of Hawaii, USA at an elevation of 11000 feet Hawaii Volcanoes National Park covers the summit and the southeastern flank of the volcano, including a separate volcano, Kīlauea. Hawaii Volcanoes National Park, established in 1916 is a United States National Park located in the U Kīlauea (kiːlauea is an active Volcano in the Hawaiian Islands, one of five Shield volcanoes that together form the Island of Hawai{{okina}}i

Structure

Clouds over Mauna Loa

Mauna Loa is the world's largest shield volcano. A shield volcano is a large Volcano with shallow-sloping sides Mauna Loa is shaped like a shield, because its lava is extremely fluid (it has low viscosity), and its slopes are not steep. FLUID ( F ast L ight '''U'''ser '''I'''nterface D esigner is a graphical editor that is used to produce FLTK Source code Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. Eruptions are rarely violent, and the most common form is in the Hawaiian style, which involves lava fountains feeding lava flows. A lava fountain is a volcanic phenomenon in which Lava is forcefully but non-explosively ejected from a crater, vent or fissure. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Typically, at the start of an eruption, a rift up to several kilometers long opens, with lava fountains occurring along its length in a so-called "curtain of fire. In Geology, a rift is a place where the Earth 's crust and Lithosphere are being pulled apart and is an example of Extensional tectonics The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand " After a few days, activity normally becomes concentrated at one vent. ^[4]

Eruptions generally occur in three regions on the mountain: at the summit and in two rift zones extending northeast and southwest of the summit. A rift zone is a feature of some Volcanoes especially the Shield volcanoes of Hawaii, in which a linear series of fissures in the volcanic About 38% of eruptions in the last two hundred years have occurred at the summit, 31% in the northeast rift zone, and 25% in the southwest rift zone. The remaining 6% have occurred from vents to the northwest of the summit, away from the rift zones. ^[5] Its summit caldera is called Mokuaweoweo; it is 1. A caldera is a cauldron-like volcanic feature formed by the collapse of land following a volcanic eruption 75 to 3 miles (3–5 km) in diameter. The caldera probably formed 1,000–1,500 years ago when a very large eruption from the northeast rift zone emptied out the shallow magma chamber beneath the summit, which then collapsed. A magma chamber is a large underground pool of molten rock lying under the surface of the earth's crust ^[6]

Seismic data can reveal the locations of the magma chambers beneath the volcano which feed activity. Seismology (from Greek grc σεισμός seismos, "earthquake" and grc -λογία -logia) is the scientific study of Earthquakes Some types of seismic waves, known as "S-waves," cannot travel through liquid rock, so magma chambers cast 'shadows' in seismic data. Seismic waves are Waves that travel through the Earth, most often as the result of a tectonic Earthquake, sometimes from an Explosion S-wave can also refer to the lowest energy electronic wavefunction in atomic physics see Atomic orbital. Seismic shadows reveal a magma chamber about 1. 75 miles (3 km) beneath the summit and smaller magma bodies beneath the rift zones. ^[7]

Trade winds blow from east to west across the Hawaiian islands, and the presence of Mauna Loa strongly affects the local climate. The trade winds (also called trades) are the prevailing pattern of easterly winds found in the Tropics near the Earth's Equator. At low elevations, the eastern (windward) side of the volcano receives heavy rain, and the city of Hilo is the wettest in the United States. Hilo (ˈhiːlo is a coastal town in the State of Hawai{{okina}}i. The rainfall supports extensive forestation. A forest is an area with a high density of Trees There are many definitions of a forest based on various criteria The western (leeward) side has a much drier climate. At higher elevations, the amount of precipitation decreases, and skies are very often clear. Very low temperatures mean that precipitation often occurs in the form of snow, and the summit of Mauna Loa is described as a periglacial region, where freezing and thawing play a significant role in shaping the landscape. Periglacial is an adjective referring to places in the edges of glacial areas normally those related to past Ice ages rather than those in the modern era ^[8]

Geology and history

Origins

Mauna Loa probably began erupting between 700,000 and 1,000,000 years ago and has grown steadily since then. Like all of the Hawaiian islands, Mauna Loa has its origins in the Hawaii hotspot—a plume of magma rising from deep in the Earth's mantle. The Hawaiian Islands, once known as the Sandwich Islands, form an Archipelago of 19 Islands and Atolls numerous smaller The Hawaii hotspot is perhaps the best known volcanic hotspot on Earth, responsible for the Hawaiian Islands in the Pacific Ocean. The mantle is a part of an Astronomical object. The interior of the Earth, similar to the other Terrestrial planets, is Chemically divided The hotspot remains in a fixed position, while the Pacific Plate drifts over it at a rate of about 4 inches (10 cm) per year. The Pacific Plate is an oceanic Tectonic plate beneath the Pacific Ocean. The upwelling of the hot magma creates volcanoes, and each individual volcano erupts for a few million years before the movement of the plate carries it away from the rising magma.

The hotspot has existed for at least 80 million years, and the Emperor Seamounts chain of old volcanoes stretches almost 3,600 miles (5,800 km) away from the hotspot. The Hawaiian-Emperor seamount chain is composed of the Hawaiian Ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Currently, the hotspot feeds activity at five volcanoes: Mauna Loa, Kīlauea, and Hualālai on the Big Island, Haleakalā on Maui, and Loʻihi, a submarine volcano south of the Big Island and the youngest Hawaiian volcano. Kīlauea (kiːlauea is an active Volcano in the Hawaiian Islands, one of five Shield volcanoes that together form the Island of Hawai{{okina}}i Hualālai is the third-most historically active Shield volcano on the Island of Hawai{{okina}}i in the Hawaiian Islands. The Island of Hawaii, also called the Big Island or Hawaii Island, is a volcanic Island in the U Haleakalā or East Maui Volcano is a massive Shield volcano that forms more than 75% of the Hawaiian Island of Maui. The Island of Maui is the second-largest of the Hawaiian Islands at 727 Lōihi is a Seamount and undersea Volcano in the Hawaiian archipelago, located at 18 Mauna Loa is the largest of these, although Kīlauea is currently the site of the most intense volcanic activity. ^[9]

Prehistoric eruptions

Mauna Loa erupting in 1984

Prehistoric eruptions of Mauna Loa have been extensively analyzed by carrying out radiocarbon dating on fragments of charcoal found beneath lava flows. Radiocarbon dating is a Radiometric dating method that uses the naturally occurring Radioisotope Carbon-14 (14C to determine the age of Charcoal' is the blackish residue consisting of impure Carbon obtained by removing water and other volatile constituents from Animal and Vegetation The mountain's prehistoric activity is probably the best known of any volcano. Studies have shown that a cycle occurs in which volcanic activity at the summit is dominant for several hundred years, after which activity shifts to the rift zones for several more centuries, and then back to the summit again. Two cycles have been clearly identified, each lasting 1,500–2,000 years. This cyclical behavior is unique to Mauna Loa among the Hawaiian volcanoes. ^[10]

Records show that between about 7,000 and 6,000 years ago Mauna Loa was largely inactive. The cause of this cessation in activity is not known, and no known similar hiatus has been found at other Hawaiian volcanoes except for those currently in the post-shield stage. Between 11,000 and 8,000 years ago, activity was more intense than it is today. ^[5] However, Mauna Loa's overall rate of growth has probably begun to slow over the last 100,000 years,^[11] and the volcano may in fact be nearing the end of its tholeiitic basalt shield-building phase. Tholeiitic basalt is an Igneous rock, a type of Basalt. Like all basalt the rock type is dominated by Clinopyroxene plus Plagioclase, with minor ^[12]

First recorded ascent

The first recorded ascent of Mauna Loa was in 1794 by the naturalist Archibald Menzies, the then-Lieutenant Joseph Baker, and two others. Archibald Menzies (pronounced or Ming-iss, see Yogh) 15 March 1754 &ndash 15 February 1842) was a Scottish Joseph Baker (1767- 1817 was an officer in the Royal Navy, best known for his role in the mapping of the Pacific Northwest Coast of America during the Vancouver Expedition ^[13][14] Using a barometer, Menzies calculated its height within 50 feet (15 m). History The first barometer is thought to have been built unintentionally by Gasparo Berti, sometime between 1640 and 1643

Historic eruptions

Although native Hawaiians have witnessed eruptions for many centuries, written records exist only for eruptions that have occurred since the early 1800s. "Kanaka" redirects here For the Tamil actress see Kanaka (actress. The 19th century of the Common Era began on January 1, 1801 and ended on December 31, 1900, according to the Gregorian calendar The first historical eruption occurred in 1843, and since then 33 eruptions have been documented. In total, these eruptions have covered over 310 square miles (800 km²) of the volcano's flanks with lava flows. Typically, eruptions have been brief but intense, with 0. 06 to 0. 12 cubic miles (0. 25–0. 5 km³) of lava erupted over a few weeks.

An especially big eruption in 1935^[15] was large enough that its lava flows threatened Hilo, leading to an unusual employment of air power. Hilo (ˈhiːlo is a coastal town in the State of Hawai{{okina}}i. Five bombers of the 23d and 72d Bombardment Squadrons of the United States Air Force dropped bombs ahead of the lava in order to divert it away from Hilo. ^[16][17]

Until 1950, eruptions occurred roughly every 3–4 years, but since then the repose periods have dramatically lengthened with the only eruptions occurring in 1975 and 1984. ^[5] The two most recent eruptions have been the most extensively studied. The 1975 eruption lasted only two days and occurred at the summit of the mountain. The 1984 eruption saw fissures open up to the northwest and southeast, from the summit down to 9,500 feet (2,900 m) above sea level. Mean sea level (MSL is the average (mean height of the Sea, with reference to a suitable reference surface Flows from this eruption headed rapidly towards Hilo again, but stopped about 2. 5 miles (4. 0 km) from the outskirts when the eruption ended after three weeks. ^[9]

Current activity

Lava fountains feed ʻaʻā lava flow in March 1984. A lava fountain is a volcanic phenomenon in which Lava is forcefully but non-explosively ejected from a crater, vent or fissure. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures

The volcano has been dormant since 1984. Seismic activity remained low until 2002, when there was a sudden onset of inflation, and the caldera walls started to move apart at a rate of 2 inches (5 cm) per year. An earthquake is the result of a sudden release of energy in the Earth 's crust that creates Seismic waves Earthquakes are recorded with a Seismometer This is thought to indicate that magma is filling a reservoir about 3. 1 miles (5. 0 km) beneath the summit. The inflation has been intermittent, sometimes slowing, and sometimes stopping for several weeks. Thus far, though, it has always restarted, and this is likely to indicate an increased probability of an eruption in the next few years.

The inflation has been accompanied by increased seismic activity. A swarm of deep earthquakes began in July 2004, and continued until the end of the year. Earthquakes were detected at a rate of one per day for the first three weeks, increasing steadily over subsequent months to 15 or so per day by the end of the year. The swarm ended in December 2004, and earthquake levels have been only moderately elevated since then. ^[18]

Relationship with Kīlauea

Diagram showing the volcanoes that form the Big Island of Hawaiʻi

Kīlauea lies on the southern flank of Mauna Loa and was originally thought to be a satellite vent of Mauna Loa. The Island of Hawaii, also called the Big Island or Hawaii Island, is a volcanic Island in the U Kīlauea (kiːlauea is an active Volcano in the Hawaiian Islands, one of five Shield volcanoes that together form the Island of Hawai{{okina}}i However, chemical differences between the lavas from the two volcanoes show that they have separate shallow magma chambers. They are now considered separate volcanoes. Nevertheless, activity patterns at the two volcanoes do appear to be correlated.

The most apparent relation between the two mountains is that, generally, periods of frequent activity at one volcano coincide with periods of low activity at the other. For example, between 1934 and 1952, Kīlauea was dormant and only Mauna Loa was active, while from 1952 to 1974, only Kīlauea was active while Mauna Loa lay dormant. ^[19]

The 1984 eruption of Mauna Loa started during an eruption at Kīlauea, but had no discernible effect on the Kīlauea eruption. Occasionally, though, eruptions at one volcano do seem to influence activity at the other. The recent inflation of Mauna Loa's summit began on the same day as a new large lava flow broke out at Kīlauea's Puʻu Ōʻō crater. Puu Ōō (often written Puu Oo, and puʔu ʔoːʔoː (roughly "poo-oo oh-oh" is a cinder/spatter cone in the eastern Rift zone of the Geologists have suggested that a "pulse" of magma entering Mauna Loa's deep plumbing system could have increased pressure inside Kīlauea and triggered the eruption. ^[19]

Hazards

Volcanic eruptions in Hawaiʻi rarely cause fatalities—the only fatality due to volcanic activity there in the last century occurred at Kīlauea in 1924, when an unusually explosive eruption hurled rocks at onlookers, killing one. ^[20] However, property damage is common. Mauna Loa is a Decade Volcano, which means it has been identified as worthy of particular research in light of its frequent eruptions and proximity to populated areas. The Decade Volcanoes are 16 Volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI as being worthy Many towns and villages near the volcano are built on lava which has erupted in the last two hundred years, and there is a very strong likelihood that future eruptions will cause damage to populated areas.

Lava flows

An ʻaʻā lava flow overruns vegetation during the 1984 eruption

The main volcanic hazard at Mauna Loa is lava flows. Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Most flows advance at about walking pace and present little danger to human life, but eruptions at Mauna Loa can be more intense than those at Kīlauea; for example, the 1984 eruption emitted as much lava in three weeks as Kīlauea's current eruption produces in three years. ^[21] Such high emission rates can generate comparatively fast-moving flows.

Two eruptions of Mauna Loa have destroyed villages. In 1926, the village of Hoʻōpūloa Makai was overrun by lava flows. In 1950, the most voluminous eruption ever seen at Mauna Loa sent lava flows racing towards the sea. The village of Hoʻokena Mauka was destroyed on 2 June 1950 by the advancing flows. Events 455 - The Vandals enter Rome, and plunder the city for two weeks Year 1950 ( MCML) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar. ^[22] Hilo is partly built on lava from an 1880 eruption and is at risk from further lava flows. The brief but intense 1984 eruption saw lava flow towards Hilo, but it had not reached any buildings when the eruption stopped. ^[23]

Flank collapse

A greater but rarer hazard at Mauna Loa is the possibility of a sudden massive collapse of the volcano's flanks. Deep faults allow large portions of the sides of Hawaiian mountains to slide gradually downwards, the best known example being the Hilina Slump. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement The Hilina Slump is a 4760 cubic mile (20 kilometre³ chunk of the big island of Hawaii on the south slope of the Kilauea Volcano which is (There is also the more ancient example of the Ninole Hills. The Ninole Hills, also known as the Ninole Volcanic Series are steep eroded hills known as shield Basalts located on the south side of the Island of Hawaii ) Occasionally, a large earthquake can trigger a collapse of the flank, creating a massive landslide which may trigger a tsunami. A landslide is a geological phenomenon which includes a wide range of ground movement such as rock falls deep failure of slopes and shallow debris flows which can occur A tsunami ((tsuːˈnɑːmi is a series of waves created when Kealakekua Bay, on the western slope of Mauna Loa, was created by such an event. Kealakekua Bay is located on the Kona coast of the island of Hawai'i about 12 miles south of Kailua-Kona. Undersea surveying has revealed numerous landslides along the Hawaiian chain and two giant tsunamis are known to have occurred: 200,000 years ago, Molokaʻi experienced a 246-foot (75 m) tidal wave, and 100,000 years ago a tsunami 1,066 feet (325 m) high struck Lānaʻi. Molokai (also Molokai) is an Island in the Hawaiian archipelago. Lānai (in Hawaiian lɑːnɑʔi is the sixth-largest of the Hawaiian Islands. ^[9]

A recent example of the risks associated with slumps occurred in 1975, when the Hilina Slump suddenly moved forward by several yards. A magnitude-7. The Richter magnitude scale, or more correctly local magnitude M L scale assigns a single number to quantify the amount of seismic energy released 2 earthquake resulted which triggered a small tsunami with a wave height of a few yards. A tsunami ((tsuːˈnɑːmi is a series of waves created when ^[24]

Monitoring

A tiltmeter on Mauna Loa, used to predict eruptions by measuring very small changes in the profile of the mountain. A tiltmeter is an instrument designed to measure very small changes from the horizontal level either on the ground or in structures

Atmospheric CO₂ concentrations measured at the Mauna Loa Observatory. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single The Mauna Loa Observatory (MLO is an atmospheric baseline station on Mauna Loa volcano, on the big island of Hawaii.

Mauna Loa is an intensively monitored volcano. The Hawaiian Volcano Observatory (HVO) was established in 1912 to observe the Hawaiian volcanoes, and the HVO has developed many techniques to help predict when eruptions at Mauna Loa and other volcanoes are imminent. The Hawaiian Volcano Observatory is the Volcano observatory in Hawai&lsquoi that monitors the four active Hawaiian volcanoes Kīlauea, Mauna

One of the most important tools is seismometry. More than 60 seismometers around the Big Island enable scientists to measure the intensities and locations of hundreds of small earthquakes every week. Seismometers (from Greek Seism - "the shakes" - and Metro - "I measure" are instruments that measure and record motions of the ground including Earthquakes can begin to increase years before an eruption actually starts: The 1975 and 1984 eruptions were both preceded by one to two years of increased seismic activity at depths of less than 8 miles (13 km).

Another type of seismic activity occurs in the hours preceding an eruption. So-called harmonic tremor is a continuous "rumble" which contrasts with the normal seismic activity of sudden shocks and is believed to be caused by the rapid movement of magma underground. Harmonic tremor describes a continuous rhythmic Earthquake in the Earth's upper Lithosphere that can be detected by a Seismograph and often precedes or Volcanic tremor normally indicates an imminent eruption, although it may also be caused by shallow intrusions of magma which do not reach the surface.

Another important indicator of what is happening underground is the shape of the mountain. Tiltmeters measure very small changes in the profile of the mountain, and sensitive equipment measures distances between points on the mountain. A tiltmeter is an instrument designed to measure very small changes from the horizontal level either on the ground or in structures As magma fills the shallow reservoirs below the summit and rift zones, the mountain inflates. A survey line across the caldera measured a 3-inch (76 mm) increase in its width over the year preceding the 1975 eruption and a similar increase before the 1984 eruption. ^[9]

Observatories

The location of Mauna Loa have made it an important location for atmospheric monitoring by the Global Atmosphere Watch and other scientific observations. The Global Atmosphere Watch (GAW is a worldwide system established by the World Meteorological Organization a United Nations agency to monitor trends in the The Mauna Loa Solar Observatory (MLSO), located at 11,155 feet (3,400 m) on the northern slope of the mountain, has long been prominent in observations of the Sun. The Mauna Loa Solar Observatory (MLSO is a collection of Solar imaging instruments located on the island of Hawaii, USA at an elevation of 11000 feet The Sun (Sol is the Star at the center of the Solar System. The NOAA Mauna Loa Observatory (MLO) is located close by. The National Oceanic and Atmospheric Administration ( NOAA) is a scientific agency within the United States Department of Commerce focused on the conditions of the The Mauna Loa Observatory (MLO is an atmospheric baseline station on Mauna Loa volcano, on the big island of Hawaii. From its location well above local human-generated influences, the MLO monitors the global atmosphere, including the greenhouse gas carbon dioxide. Greenhouse gases are gaseous constituents of the atmosphere bothnatural and anthropogenic that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Measurements are adjusted to account for local degassing of CO₂ from the volcano. ^[25]

References

External links

• United States Geological Survey information page
• VolcanoWorld information
• Hawaii Center for Volcanology pages
• Global Volcanism Program entry
• Mauna Loa Observatory (MLO) – NOAA
• Mauna Loa Solar Observatory (MLSO)
• 1934 USGS color video (silent) of Mauna Loa erupting