A lava tube is a natural conduit formed by flowing lava which moves beneath the hardened surface of a lava flow. Tubes can drain lava from a volcano during an eruption, or can be extinct, meaning the lava flow has ceased, the rock has cooled and left a long cave. A lava tube is a type of lava cave formed when a low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: either by the crusting over of lava channels, or from pāhoehoe flows where the lava is moving under the surface. Lava leaves the point of eruption in channels; these channels tend to stay hot as their surroundings cool. This means they develop walls around them as the surrounding lava cools and/or as the channel melts its way deeper; these channels can get deep enough to crust over, forming an insulating tube that keeps the lava molten and serves as a conduit for the flowing lava. These types of lava tubes tend to be closer to the lava eruption point.
Farther away from the eruption point, lava can flow in an unchanneled, fan-like manner as it leaves its source, another lava tube leading back to the eruption point. Called pāhoehoe flows, these areas of surface-moving lava cool, forming either a smooth or rough, ropy surface; the lava continues to flow this way. At this point, the subsurface lava is still hot enough to break out at a point, from this point the lava begins as a new "source". Lava flows from the previous source to this breakout point as the surrounding lava of the pāhoehoe flow cools; this forms an underground channel. A broad lava-flow field consists of a main lava tube and a series of smaller tubes that supply lava to the front of one or more separate flows; when the supply of lava stops at the end of an eruption or lava is diverted elsewhere, lava in the tube system drains downslope and leaves empty caves. Such drained tubes exhibit step marks on their walls that mark the various depths at which the lava flowed, known as flow ledges or flow lines depending on how prominently they protrude from the walls.
Lava tubes have pāhoehoe floors, although this may be covered in breakdown from the ceiling. A variety of speleothems may be found in lava tubes including a variety of stalactite forms known as lavacicles, which can be of the splash, shark tooth, or tubular variety. Lavacicles are the most common of lava tube speleothems. Drip stalagmites may form under tubular lava stalactites, the latter may grade into a form known as a tubular lava helictite. A runner is a bead of lava, extruded from a small opening and runs down a wall. Lava tubes may contain mineral deposits that most take the form of crusts or small crystals, less as stalactites and stalagmites. Lava tubes can be up to 14–15 metres wide, though are narrower, run anywhere from 1–15 metres below the surface. Lava tubes can be long. A lava tube system in Kiama, consists of over 20 tubes, many of which are breakouts of a main lava tube; the largest of these lava tubes is 2 meters in diameter and has columnar jointing due to the large cooling surface.
Other tubes have radial jointing features. The tubes are infilled due to the low slope angle of emplacement. By far the largest known lava tubes in the Solar System are on Venus. Lunar lava tubes have been discovered and have been studied as possible human habitats, providing natural shielding from radiation. Martian lava tubes are associated with innumerable lava flows and lava channels on the flanks of Olympus Mons. Collapsed lava tubes are visible as chains of pit craters, broad lava fans formed by lava emerging from intact, subsurface tubes are common. Iceland Raufarhólshellir Surtshellir – For a long time, this was the longest known lava tube in the world. Kenya Leviathan Cave – At 12.5 kilometres, it is the longest lava tube in Africa. Portugal Gruta das Torres – Lava tube system of the Azores. South Korea Manjang Cave – more than 8 kilometers long, located in Jeju Island, is a popular tourism spot. Spain Cueva de los Verdes – Lava tube system. Lanzarote, Canary Islands. United States Kazumura Cave, Hawaii – Not only the world's most extensive lava tube, but at 40.7 miles has the greatest linear extent of any cave known.
Lava River Cave in Oregon's Newberry National Volcanic Monument – Newberry National Volcanic Monument Ape Cave, Washington – May be the third longest lava tube in the continental United States. Caving – Recreational pastime of exploring cave systems Geology of the Moon – Structure and composition of the Moon Lava cave – Cave formed in volcanic rock one formed via volcanic processes Mars habitat Speleology – Science of cave and karst systems Speleothem – A structure formed in a cave by the deposition of minerals from water
A missionary is a member of a religious group sent into an area to proselytize or perform ministries of service, such as education, social justice, health care, economic development. The word "mission" originates from 1598 when the Jesuits sent members abroad, derived from the Latin missionem, meaning "act of sending" or mittere, meaning "to send"; the word was used in light of its biblical usage. The term is most used for Christian missions, but can be used for any creed or ideology. A Christian missionary can be defined as "one, to witness across cultures"; the Lausanne Congress of 1974, defined the term, related to Christian mission as, "to form a viable indigenous church-planting movement". Missionaries can be found in many countries around the world. In the Bible, Jesus is recorded as instructing the apostles to make disciples of all nations; this verse is referred to by Christian missionaries as the Great Commission and inspires missionary work. The Christian Church expanded throughout the Roman Empire in New Testament times and is said by tradition to have reached further, to Persia and to India.
During the Middle Ages, the Christian monasteries and missionaries such as Saint Patrick, Adalbert of Prague propagated learning and religion beyond the European boundaries of the old Roman Empire. In 596, Pope Gregory the Great sent the Gregorian Mission into England. In their turn, Christians from Ireland and from Britain became prominent in converting the inhabitants of central Europe. During the Age of Discovery, the Catholic Church established a number of missions in the Americas and in other Western colonies through the Augustinians and Dominicans to spread Christianity in the New World and to convert the Native Americans and other indigenous people. About the same time, missionaries such as Francis Xavier as well as other Jesuits, Augustinians and Dominicans reached Asia and the Far East, the Portuguese sent missions into Africa. Emblematic in many respects is Matteo Ricci's Jesuit mission to China from 1582, peaceful and non-violent; these missionary movements should be distinguished from others, such as the Baltic Crusades of the 12th and 13th centuries, which were arguably compromised in their motivation by designs of military conquest.
Much contemporary Catholic missionary work has undergone profound change since the Second Vatican Council of 1962-1965, with an increased push for indigenization and inculturation, along with social justice issues as a constitutive part of preaching the Gospel. As the Catholic Church organizes itself along territorial lines and had the human and material resources, religious orders, some specializing in it, undertook most missionary work in the era after the collapse of the Roman Empire in the West. Over time, the Holy See established a normalized Church structure in the mission areas starting with special jurisdictions known as apostolic prefectures and apostolic vicariates. At a stage of development these foundations are raised to regular diocesan status with a local bishops appointed. On a global front, these processes were accelerated in the 1960s, in part accompanying political decolonization. In some regions, they are still in course. Just as the Bishop of Rome had jurisdiction in territories considered to be in the Eastern sphere, so the missionary efforts of the two 9th-century saints Cyril and Methodius were conducted in relation to the West rather than the East, though the field of activity was central Europe.
The Eastern Orthodox Church, under the Orthodox Church of Constantinople undertook vigorous missionary work under the Roman Empire and its successor the Byzantine Empire. This had lasting effects and in some sense is at the origin of the present relations of Constantinople with some sixteen Orthodox national churches including the Romanian Orthodox Church, the Georgian Orthodox and Apostolic Church, the Ukrainian Orthodox Church, the Bulgarian Orthodox Church; the Byzantines expanded their missionary work in Ukraine after the mass baptism in Kiev in 988. The Serbian Orthodox Church had its origins in the conversion by Byzantine missionaries of the Serb tribes when they arrived in the Balkans in the 7th century. Orthodox missionaries worked among the Estonians from the 10th to the 12th centuries, founding the Estonian Orthodox Church. Under the Russian Empire of the 19th century, missionaries such as Nicholas Ilminsky moved into the subject lands and propagated Orthodoxy, including through Belarus, Moldova, Estonia and China.
The Russian St. Nicholas of Japan took Eastern Orthodoxy to Japan in the 19th century; the Russian Orthodox Church sent missionaries to Alaska beginning in the 18th century, including Saint Herman of Alaska, to minister to the Native Americans. The Russian Orthodox Church Outside Russia continued missionary work outside Russia after the 1917 Russian Revolution, resulting in the establishment of many new dioceses in the diaspora, from which numerous converts have been made in Eastern Europe, North America, Oceania. Early Protestant missionaries included John Eliot and contemporary ministers
A national park is a park in use for conservation purposes. It is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently, there is a common idea: the conservation of'wild nature' for posterity and as a symbol of national pride. An international organization, the International Union for Conservation of Nature, its World Commission on Protected Areas, has defined "National Park" as its Category II type of protected areas. While this type of national park had been proposed the United States established the first "public park or pleasuring-ground for the benefit and enjoyment of the people", Yellowstone National Park, in 1872. Although Yellowstone was not termed a "national park" in its establishing law, it was always termed such in practice and is held to be the first and oldest national park in the world. However, the Tobago Main Ridge Forest Reserve, the area surrounding Bogd Khan Uul Mountain are seen as the oldest protected areas, predating Yellowstone by nearly a century.
The first area to use "national park" in its creation legislation was the U. S.'s Mackinac, in 1875. Australia's Royal National Park, established in 1879, was the world's third official national park. In 1895 ownership of Mackinac National Park was transferred to the State of Michigan as a state park and national park status was lost; as a result, Australia's Royal National Park is by some considerations the second oldest national park now in existence. Canada established Parks Canada in 1911, becoming the world's first national service dedicated to protecting and presenting natural and historical treasures; the largest national park in the world meeting the IUCN definition is the Northeast Greenland National Park, established in 1974. According to the IUCN, 6,555 national parks worldwide met its criteria in 2006. IUCN is still discussing the parameters of defining a national park. National parks are always open to visitors. Most national parks provide outdoor recreation and camping opportunities as well as classes designed to educate the public on the importance of conservation and the natural wonders of the land in which the national park is located.
In 1969, the IUCN declared a national park to be a large area with the following defining characteristics: One or several ecosystems not materially altered by human exploitation and occupation, where plant and animal species, geomorphological sites and habitats are of special scientific and recreational interest or which contain a natural landscape of great beauty. In 1971, these criteria were further expanded upon leading to more clear and defined benchmarks to evaluate a national park; these include: Minimum size of 1,000 hectares within zones in which protection of nature takes precedence Statutory legal protection Budget and staff sufficient to provide sufficient effective protection Prohibition of exploitation of natural resources qualified by such activities as sport, fishing, the need for management, etc. While the term national park is now defined by the IUCN, many protected areas in many countries are called national park when they correspond to other categories of the IUCN Protected Area Management Definition, for example: Swiss National Park, Switzerland: IUCN Ia - Strict Nature Reserve Everglades National Park, United States: IUCN Ib - Wilderness Area Victoria Falls National Park, Zimbabwe: IUCN III - National Monument Vitosha National Park, Bulgaria: IUCN IV - Habitat Management Area New Forest National Park, United Kingdom: IUCN V - Protected Landscape Etniko Ygrotopiko Parko Delta Evrou, Greece: IUCN VI - Managed Resource Protected AreaWhile national parks are understood to be administered by national governments, in Australia national parks are run by state governments and predate the Federation of Australia.
In Canada, there are both national parks operated by the federal government and provincial or territorial parks operated by the provincial and territorial governments, although nearly all are still national parks by the IUCN definition. In many countries, including Indonesia, the Netherlands, the United Kingdom, national parks do not adhere to the IUCN definition, while some areas which adhere to the IUCN definition are not designated as national parks. In 1810, the English poet William Wordsworth described the Lake District as a sort of national property, in which every man has a right and interest who has an eye to perceive and a heart to enjoy; the painter George Catlin, in his travels through the American West, wrote during the 1830s that the Native Americans in the United States might be preserved...in a magnificent park... A nation's Park, containing man and beast, in all the wild and freshness of their nature's beauty! The first effort by the U. S. Federal government to set aside such protected lands was on 20 April 1832, when President Andrew Jackson signed legislation that the 22nd United States Congress had enacted to set aside four sections of land around what is now Hot Springs, Arkansas, to protect the natural, thermal springs and adjoining mountainsides for the futur
World Heritage Site
A World Heritage Site is a landmark or area, selected by the United Nations Educational and Cultural Organization as having cultural, scientific or other form of significance, is protected by international treaties. The sites are judged important to the collective interests of humanity. To be selected, a World Heritage Site must be an classified landmark, unique in some respect as a geographically and identifiable place having special cultural or physical significance, it may signify a remarkable accomplishment of humanity, serve as evidence of our intellectual history on the planet. The sites are intended for practical conservation for posterity, which otherwise would be subject to risk from human or animal trespassing, unmonitored/uncontrolled/unrestricted access, or threat from local administrative negligence. Sites are demarcated by UNESCO as protected zones; the list is maintained by the international World Heritage Program administered by the UNESCO World Heritage Committee, composed of 21 "states parties" that are elected by their General Assembly.
The programme catalogues and conserves sites of outstanding cultural or natural importance to the common culture and heritage of humanity. Under certain conditions, listed sites can obtain funds from the World Heritage Fund; the program began with the Convention Concerning the Protection of the World's Cultural and Natural Heritage, adopted by the General Conference of UNESCO on 16 November 1972. Since 193 state parties have ratified the convention, making it one of the most recognized international agreements and the world's most popular cultural program; as of July 2018, a total of 1,092 World Heritage Sites exist across 167 countries. Italy, with 54 sites, has the most of any country, followed by China, France, Germany and Mexico. In 1954, the government of Egypt decided to build the new Aswan High Dam, whose resulting future reservoir would inundate a large stretch of the Nile valley containing cultural treasures of ancient Egypt and ancient Nubia. In 1959, the governments of Egypt and Sudan requested UNESCO to assist their countries to protect and rescue the endangered monuments and sites.
In 1960, the Director-General of UNESCO launched an appeal to the member states for an International Campaign to Save the Monuments of Nubia. This appeal resulted in the excavation and recording of hundreds of sites, the recovery of thousands of objects, as well as the salvage and relocation to higher ground of a number of important temples, the most famous of which are the temple complexes of Abu Simbel and Philae; the campaign, which ended in 1980, was considered a success. As tokens of its gratitude to countries which contributed to the campaign's success, Egypt donated four temples: the Temple of Dendur was moved to the Metropolitan Museum of Art in New York City, the Temple of Debod was moved to the Parque del Oeste in Madrid, the Temple of Taffeh was moved to the Rijksmuseum van Oudheden in the Netherlands, the Temple of Ellesyia to Museo Egizio in Turin; the project cost $80 million, about $40 million of, collected from 50 countries. The project's success led to other safeguarding campaigns: saving Venice and its lagoon in Italy, the ruins of Mohenjo-daro in Pakistan, the Borobodur Temple Compounds in Indonesia.
UNESCO initiated, with the International Council on Monuments and Sites, a draft convention to protect the common cultural heritage of humanity. The United States initiated the idea of cultural conservation with nature conservation; the White House conference in 1965 called for a "World Heritage Trust" to preserve "the world's superb natural and scenic areas and historic sites for the present and the future of the entire world citizenry". The International Union for Conservation of Nature developed similar proposals in 1968, they were presented in 1972 to the United Nations Conference on the Human Environment in Stockholm. Under the World Heritage Committee, signatory countries are required to produce and submit periodic data reporting providing the World Heritage Committee with an overview of each participating nation's implementation of the World Heritage Convention and a "snapshot" of current conditions at World Heritage properties. A single text was agreed on by all parties, the "Convention Concerning the Protection of the World Cultural and Natural Heritage" was adopted by the General Conference of UNESCO on 16 November 1972.
The Convention came into force on 17 December 1975. As of May 2017, it has been ratified by 193 states parties, including 189 UN member states plus the Cook Islands, the Holy See and the State of Palestine. Only four UN member states have not ratified the Convention: Liechtenstein, Nauru and Tuvalu. A country must first list its significant natural sites. A country may not nominate sites. Next, it can place sites selected from that list into a Nomination File; the Nomination File is evaluated by the International Council on Monuments and Sites and the World Conservation Union. These bodies make their recommendations to the World Heritage Committee; the Committee meets once per year to determine whether or not to inscribe each nominated property on the World Heritage List and sometimes defers or refers the decision to request more information from the country which nominated the site. There are ten selection criteria – a site must meet at least one of them to be included on the list
John Muir known as "John of the Mountains" and "Father of the National Parks", was an influential Scottish-American naturalist, environmental philosopher and early advocate for the preservation of wilderness in the United States of America. His letters and books describing his adventures in nature in the Sierra Nevada, have been read by millions, his activism has helped to preserve the Yosemite Valley, Sequoia National Park and many other wilderness areas. The Sierra Club, which he co-founded, is a prominent American conservation organization. In his life, Muir devoted most of his time to the preservation of the Western forests; as part of the campaign to make Yosemite a national park, Muir published two landmark articles on wilderness preservation in The Century Magazine, "The Treasures of the Yosemite" and "Features of the Proposed Yosemite National Park". S. Congress to pass a bill in 1890 establishing Yosemite National Park; the spiritual quality and enthusiasm toward nature expressed in his writings has inspired readers, including presidents and congressmen, to take action to help preserve large nature areas.
John Muir has been considered "an inspiration to both Scots and Americans". Muir's biographer, Steven J. Holmes, believes that Muir has become "one of the patron saints of twentieth-century American environmental activity," both political and recreational; as a result, his writings are discussed in books and journals, he is quoted by nature photographers such as Ansel Adams. "Muir has profoundly shaped the categories through which Americans understand and envision their relationships with the natural world," writes Holmes. Muir was noted for being an ecological thinker, political spokesman, religious prophet, whose writings became a personal guide into nature for countless individuals, making his name "almost ubiquitous" in the modern environmental consciousness. According to author William Anderson, Muir exemplified "the archetype of our oneness with the earth", while biographer Donald Worster says he believed his mission was "saving the American soul from total surrender to materialism." On April 21, 2013, the first John Muir Day was celebrated in Scotland, which marked the 175th anniversary of his birth, paying homage to the conservationist.
John Muir's Birthplace is a four-story stone house in East Lothian, Scotland. His parents were Ann Gilrye, he was the third of eight children: Margaret, David, Daniel and Mary, the American-born Joanna. His earliest recollections were of taking short walks with his grandfather. In his autobiography, he described his boyhood pursuits, which included fighting, either by re-enacting romantic battles from the Wars of Scottish Independence or just scrapping on the playground, hunting for birds' nests. Author Amy Marquis notes that he began his "love affair" with nature while young, implies that it may have been in reaction to his strict religious upbringing. "His father believed that anything that distracted from Bible studies was frivolous and punishable." But the young Muir was a "restless spirit" and "prone to lashings." As a young boy, Muir became fascinated with the East Lothian landscape, spent a lot of time wandering the local coastline and countryside. It was during this time that he became interested in natural history and the works of Scottish naturalist Alexander Wilson.
Although he spent the majority of his life in America, Muir never forgot his roots in Scotland. He held a strong connection with his birthplace and Scottish identity throughout his life and was heard talking about his childhood spent amid the East Lothian countryside, he admired the works of Thomas Carlyle and poetry of Robert Burns. He returned to Scotland on a trip in 1893, where he met one of his Dunbar schoolmates and visited the places of his youth that were etched in his memory, he never lost his strong Scottish accent despite having lived in America for many years. In 1849, Muir's family immigrated to the United States, starting a farm near Portage, called Fountain Lake Farm, it has been designated a National Historic Landmark. Stephen Fox recounts that Muir's father found the Church of Scotland insufficiently strict in faith and practice, leading to their immigration and joining a congregation of the Campbellite Restoration Movement, called the Disciples of Christ. By the age of 11, the young Muir had learned to recite "by heart and by sore flesh" all of the New Testament and most of the Old Testament.
In maturity, while remaining a spiritual man, Muir may have changed his orthodox beliefs. He wrote, "I never tried to abandon creeds or code of civilization. Elsewhere in his writings, he described the conventional image of a Creator, "as purely a manufactured article as any puppet of a half-penny theater." When he was 22 years old, Muir enrolled at the University of Wisconsin–Madison, paying his own way for several years. There, under a towering black locust tree beside North Hall, Muir took his first botany lesson. A fellow student plucked a flower from the tree and used it to explain how the grand locust is a member of the pea family, related to the straggling pea plant. Fifty years the naturalist Muir described the day in his autobiography. "This fine lesson charmed me and sent me flying to the woods and meadows in wild enthusiasm." As a freshman, Muir studied chemistry with Profes
Mauna Loa is one of five volcanoes that form the Island of Hawaii in the U. S. state of Hawaiʻi in the Pacific Ocean. The largest subaerial volcano in both mass and volume, Mauna Loa has been considered the largest volcano on Earth, dwarfed only by Tamu Massif, it is an active shield volcano with gentle slopes, with a volume estimated at 18,000 cubic miles, although its peak is about 125 feet lower than that of its neighbor, Mauna Kea. Lava eruptions from Mauna Loa are silica-poor and fluid, they tend to be non-explosive. Mauna Loa has been erupting for at least 700,000 years, may have emerged above sea level about 400,000 years ago; the oldest-known dated rocks are not older than 200,000 years. The volcano's magma comes from the Hawaii hotspot, responsible for the creation of the Hawaiian island chain over tens of millions of years; the slow drift of the Pacific Plate will carry Mauna Loa away from the hotspot within 500,000 to one million years from now, at which point it will become extinct.
Mauna Loa's most recent eruption occurred from March 24 to April 15, 1984. No recent eruptions of the volcano have caused fatalities, but eruptions in 1926 and 1950 destroyed villages, the city of Hilo is built on lava flows from the late 19th century; because of the potential hazards it poses to population centers, Mauna Loa is part of the Decade Volcanoes program, which encourages studies of the world's most dangerous volcanoes. Mauna Loa has been monitored intensively by the Hawaiian Volcano Observatory since 1912. Observations of the atmosphere are undertaken at the Mauna Loa Observatory, of the Sun at the Mauna Loa Solar Observatory, both located near the mountain's summit. Hawaii Volcanoes National Park covers the summit and the southeastern flank of the volcano, incorporates Kīlauea, a separate volcano. Like all Hawaiian volcanoes, Mauna Loa was created as the Pacific tectonic plate moved over the Hawaii hotspot in the Earth's underlying mantle; the Hawaii island volcanoes are the most recent evidence of this process that, over 70 million years, has created the 3,700 mi -long Hawaiian–Emperor seamount chain.
The prevailing view states that the hotspot has been stationary within the planet's mantle for much, if not all of the Cenozoic Era. However, while the Hawaiian mantle plume is well understood and extensively studied, the nature of hotspots themselves remains enigmatic. Mauna Loa is one of five subaerial volcanoes; the oldest volcano on the island, Kohala, is more than a million years old, Kīlauea, the youngest, is believed to be between 300,000 and 600,000 years of age. Lōʻihi Seamount on the island's flank is younger, but has yet to breach the surface of the Pacific Ocean. At 1 million to 700,000 years of age, Mauna Loa is the second youngest of the five volcanoes on the island, making it the third youngest volcano in the Hawaiian – Emperor seamount chain, a chain of shield volcanoes and seamounts extending from Hawaii to the Kuril–Kamchatka Trench in Russia. Following the pattern of Hawaiian volcano formation, Mauna Loa would have started as a submarine volcano building itself up through underwater eruptions of alkali basalt before emerging from the sea through a series of surtseyan eruptions about 400,000 years ago.
Since the volcano has remained active, with a history of effusive and explosive eruptions, including 33 eruptions since the first well-documented eruption in 1843. Although Mauna Loa's activity has been overshadowed in recent years by that of its neighbor Kīlauea, it remains active. Mauna Loa is the largest subaerial and second largest overall volcano in the world, covering a land area of 5,271 km2 and spans a maximum width of 120 km. Consisting of 65,000 to 80,000 km3 of solid rock, it makes up more than half of the surface area of the island of Hawaiʻi. Combining the volcano's extensive submarine flanks and 4,170 m subaerial height, Mauna Loa rises 9,170 m from base to summit, greater than the 8,848 m or 29,029 ft elevation of Mount Everest from sea level to its summit. In addition, much of the mountain is invisible underwater: its mass depresses the crust beneath it by another 8 km, in the shape of an inverse mountain, meaning the total height of Mauna Loa from the start of its eruptive history is about 17,170 m.
Mauna Loa is a typical shield volcano in form, taking the shape of a long, broad dome extending down to the ocean floor whose slopes are about 12° at their steepest, a consequence of its fluid lava. The shield-stage lavas that built the enormous main mass of the mountain are tholeiitic basalts, like those of Mauna Kea, created through the mixing of primary magma and subducted oceanic crust. Mauna Loa's summit hosts three overlapping pit craters arranged northeast-southwest, the first and last 1 km in diameter and the second an oblong 4.2 km × 2.5 km feature. Mokuʻāweoweo's caldera floor lies between 170 and 50 m beneath its rim and it is only the latest of several calderas that have formed and reformed over the volcano's life, it was created between 1,000 and 1,500 years ago by a large eruption from Mauna Loa's northeast rift zone, which emptied out a shallow magma chamber beneath the summit and collapsed it into its pres
Hawaiʻi is the largest island located in the U. S. state of Hawaii. It is the largest and the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of 4,028 square miles, it has 63% of the Hawaiian archipelago's combined landmass, is the largest island in the United States. However, it has only 13% of Hawaiʻi's people; the island of Hawaiʻi is the third largest island in Polynesia, behind the two main islands of New Zealand. The island is referred to as the Island of Hawaiʻi, the Big Island, or Hawaiʻi Island to distinguish it from the state. Administratively, the whole island encompasses Hawaiʻi County; as of the 2010 Census the population was 185,079. The county seat and largest city is Hilo. There are no incorporated cities in Hawaiʻi County. Hawaiʻi is said to have been named after Hawaiʻiloa, the legendary Polynesian navigator who first discovered it. Other accounts attribute the name to the legendary realm of Hawaiki, a place from which some Polynesian people are said to have originated, the place where they transition to in the afterlife, or the realm of the gods and goddesses.
Captain James Cook, the English explorer and navigator, captain of the first European expedition that discovered the Hawaiian Islands, called them the "Sandwich Islands" after his patron, the Earl of Sandwich. Cook was killed on the Big Island at Kealakekua Bay on 14 February 1779, in a mêlée which followed the theft of a ship's boat. Hawaiʻi was the home island of Paiʻea Kamehameha known as Kamehameha the Great. Kamehameha united most of the Hawaiian islands under his rule in 1795, after several years of war, gave the kingdom and the island chain the name of his native island. According to the U. S. Census Bureau, the county has a total area of 5,086 square miles, of which 4,028 square miles is land and 1,058 square miles is water; the county's land area comprises 62.7 percent of the state's land area. It is the highest percentage by any county in the United States. At its greatest dimension, the island is 93 miles across, it has a land area of 4,028 square miles comprising 62% of the Hawaiian Islands' land area.
Measured from its sea floor base to its highest peak, Mauna Kea is the world's tallest mountain, taller than Mount Everest, since the base of Mount Everest is above sea level. Ka Lae, the southernmost point in the 50 states of the United States, is on Hawaii; the nearest landfall to the south is in the Line Islands. To the northwest of the island of Hawaii is the island of Maui, whose Haleakalā volcano is visible from Hawaii across the Alenuihaha Channel; the island of Hawaiʻi is built from five separate shield volcanoes that erupted somewhat sequentially, one overlapping the other. These are: Kohala – extinct Mauna Kea – dormant Hualālai – active Mauna Loa – active within Hawaiʻi Volcanoes National Park Kīlauea – active: erupting continuously from 1983 to 2018. Geologists now consider these "outcrops" to be part of the earlier building of Mauna Loa; because Mauna Loa and Kīlauea are active volcanoes, the island of Hawaii is still growing. Between January 1983 and September 2002, lava flows added 543 acres to the island.
Lava flowing from Kīlauea has destroyed several towns, including Kapoho in 1960, Kalapana and Kaimū in 1990. In 1987 lava filled in "Queen's Bath", a large, L-shaped, freshwater pool in the Kalapana area; some geologists count seven volcanoes as building the island, which include the submarine volcanoes Māhukona and Lōʻihi as parts of the base of the island. Māhukona off the northwest corner of the island has disappeared below the surface of the ocean. 22 miles southeast of Hawaii lies the undersea volcano known as Lōʻihi. It is an erupting seamount that now reaches 3,200 feet below the surface of the ocean. Continued activity at current rates from Lōʻihi will cause it to break the surface of the ocean sometime between 10,000 and 100,000 years from now; the Great Crack is an eight-mile-long, 60-foot-wide and 60-foot-deep fissure in the island, in the district of Kau. According to the United States Geological Survey, the Great Crack is the result of crustal dilation from magmatic intrusions into the southwest rift zone of Kilauea.
While neither the earthquake of 1868 nor that of 1975 caused a measurable change in the Great Crack, lava welled out of the lower 6 miles of the Great Crack in 1823. Visitors can find trails, rock walls, archaeological sites from as old as the 12th century around the Great Crack. 1,951 acres of private land were purchased during the presidency of Bill Clinton to protect various artifacts in this area, as well as the habitat of local wildlife. The Hilina Slump is a 4,760-cubic-mile section of the south slope of the Kīlauea volcano, slipping away from the island. Between 1990 and 1993, Global Positioning System measurements showed a southward displacement of about 4 inches per year. Undersea measurements show that a "bench" has formed a buttress and that this buttress may tend to reduce the likelihood of future catastrophic detachment. On 2 April 1868, an earthquake with a magnitude estimated between 7.25 and 7.9 rocked the southeast coast of Hawaii. This was the most destructive earthquake in the recorded history of Hawaii.