Koʻolau Range is a name given to the dormant fragmented remnant of the eastern or windward shield volcano of the Hawaiian island of Oʻahu. It was designated a National Natural Landmark in 1972, it is not a mountain range in the normal sense, because it was formed as a single mountain called Koʻolau Volcano. What remains of Koʻolau is the western half of the original volcano, destroyed in prehistoric times when the entire eastern half—including much of the summit caldera—slid cataclysmically into the Pacific Ocean. Remains of this ancient volcano lie as massive fragments strewn nearly 100 miles over the ocean floor to the northeast of Oʻahu. Kāneʻohe Bay is; the modern Koʻolau mountain forms Oʻahu's windward coast and rises behind the leeward coast city of Honolulu — on its leeward slopes and valleys are located most of Honolulu's residential neighborhoods. The volcano is thought to have first erupted on the ocean floor more than 2.5 million years ago. It reached sea level and continued to grow in elevation until about 1.7 million years ago, when the volcano became dormant.
The volcano remained dormant for hundreds of thousands of years, during which time erosion ate away at the smooth slopes of the shield-shaped mountain. The highest elevation exceeded 3,000 meters. After hundreds of thousands of years of dormancy, Koʻolau volcano began to erupt again; some thirty eruptions over the past 500,000 years or so have created many of the landmarks around eastern Oʻahu, such as Diamond Head, Koko Head, Koko Crater, Punchbowl Crater, Āliapaʻakai, are collectively known as the Honolulu Volcanic Series. Geologists do not always agree on the dates of these more recent eruptions, some dating them to around 32,000 years ago, others to as as 10,000 years ago. Geologists believe that there is at least a remote possibility that Koʻolau volcano will erupt again. There are three roads that tunnel through the southern part of the Koʻolau Range, connecting Honolulu to the Windward Coast. From leeward to windward: Hawaii Route 61 Hawaii Route 63 Interstate H-3
In marine geology, a guyot known as a tablemount, is an isolated underwater volcanic mountain with a flat top more than 200 m below the surface of the sea. The diameters of these flat summits can exceed 10 km. Guyots are most found in the Pacific Ocean, but they have been identified in all the oceans except the Arctic Ocean. Guyots were first recognized in 1945 by Harry Hammond Hess, who collected data using echo-sounding equipment on a ship he commanded during World War II, his data showed. Hess called these undersea mountains "guyots", because they resembled the flat-roofed biology and geology building at Princeton University, Guyot Hall, named after the 19th-century geographer Arnold Henry Guyot. Hess postulated they were once volcanic islands that were beheaded by wave action, yet they are now deep under sea level; this idea was used to help bolster the theory of plate tectonics. Guyots show evidence of having once been above the surface, with gradual subsidence through stages from fringed reefed mountain, coral atoll, a flat-topped submerged mountain.
Seamounts are made by extrusion of lavas piped upward in stages from sources within the Earth's mantle hotspots, to vents on the seafloor. The volcanism invariably ceases after a time, other processes dominate; when an undersea volcano grows high enough to be near or breach the ocean surface, wave action and/or coral reef growth tend to create a flat-topped edifice. However, all ocean crust and guyots form from hot magma and/or rock; as the lithosphere that the future guyot rides on cools, it becomes denser and sinks lower into Earth's mantle, through the process of isostasy. This is the same process that gives rise to higher seafloor topography at oceanic ridges, such as the Mid-Atlantic Ridge in the Atlantic Ocean, deeper ocean at abyssal plains and oceanic trenches, such as the Mariana Trench. Thus, the island or shoal that will become a guyot subsides over millions of years. In the right climatic regions, coral growth can sometimes keep pace with the subsidence, resulting in coral atoll formation, but the corals dip too deep to grow and the island becomes a guyot.
The greater the amount of time that passes, the deeper the guyots become. Seamounts provide data on movements of tectonic plates on which they ride, on the rheology of the underlying lithosphere; the trend of a seamount chain traces the direction of motion of the lithospheric plate over a more or less fixed heat source in the underlying asthenosphere, the part of the Earth's mantle beneath the lithosphere. There are thought to be up to an estimated 50,000 seamounts in the Pacific basin; the Hawaiian–Emperor seamount chain is an excellent example of an entire volcanic chain undergoing this process, from active volcanism, to coral reef growth, to atoll formation, to subsidence of the islands and becoming guyots. The steepness gradient of most guyots is about 20 degrees. To technically be considered a guyot or tablemount, they must stand at least 900 m tall. One guyot in particular, the Great Meteor Tablemount in the Northeast Atlantic Ocean, stands at more than 4,000 m high, with a diameter of 110 km.
However, there are many undersea mounts that can range from just less than 90 m to around 900 m. Large oceanic volcanic constructions, hundreds of kilometres across, are called oceanic plateaus. Guyots are much larger in area than typical seamounts. There are 283 guyots in the world's oceans, with the North Pacific having 119, South Pacific 77, South Atlantic 43, Indian Ocean 28, North Atlantic 8, Southern Ocean 6, the Mediterranean 2 guyots. Guyots are associated with specific lifeforms and varying amounts of organic matter. Local increases in chlorophyll a, enhanced carbon incorporation rates and changes in phytoplankton species composition were associated with the seamount. Evolution of Hawaiian volcanoes Hotspot Kodiak–Bowie Seamount chain New England Seamounts Seamount Wilde guyot map from Texas A&M
Puʻu ʻŌʻō is a volcanic cone in the eastern rift zone of the Kīlauea volcano of the Hawaiian Islands. Until the end of April 2018, Puʻu ʻŌʻō had been erupting nearly continuously since January 3, 1983, making it the longest-lived rift-zone eruption of the last two centuries. By January 2005, 2.7 cubic kilometers of magma covered an area of more than 117 square kilometers and added 230 acres of land to the southeast coast of Hawaiʻi. So far, the eruption has claimed 189 buildings and 14 kilometers of highways, as well as a church, a store, the Wahaʻula Visitor Center, many ancient Hawaiian sites, including the Wahaʻula heiau; the coastal highway has been closed since 1987, as parts of the road have been buried under lava up to 35 meters thick. The hill was nicknamed "Puʻu O" by volcanologists, as its position when marked on a map of the area coincided with an "o" in "Lava flow of 1965"; the elders of the village of Kalapana were asked to name the new hill, chose Puʻu ʻŌʻō, meaning hill of the digging stick.
The name is often translated as "Hill of the ʻŌʻō Bird". The Puʻu ʻŌʻō eruption began when fissures split the ground in the remote rainforest of the eastern rift zone, on January 3, 1983. By June 1983, the activity had localized to the Puʻu ʻŌʻō vent. Over the next three years, 44 eruptive episodes with lava fountains as high as 460 meters stopped traffic at points across east Hawaiʻi; the fallout of cinder and spatter from the towering lava fountains built a cone 255 meters high. In July 1986, the conduit feeding magma to Puʻu ʻŌʻō ruptured, the eruption abruptly shifted 3 kilometers downrift to form the Kūpaʻianahā vent. With the new vent came a new style of eruption: continuous, quiet effusion from a lava lake replaced the episodic high fountaining. After a few weeks, a roof formed over the main lava outflow channel; the lava tube allowed the fluid pahoehoe lava to flow long distances. In less than a year, overflow from the lake created a broad and low shield about 55 meters above Kūpaʻianahā.
Lava streams were first visible from the town of Kapaʻau in November, 1986. In the course of that month, lava cut a swath through Kapaʻahu, covered the coastal highway, reached the ocean 12 kilometers from the vent; some weeks the lava flow shifted eastwards and buried 14 houses in the town of Kalapana within one day. The lava flow at Kalapana ceased. In 1990, the eruption entered its most destructive phase, when flows turned eastward and destroyed the villages of Kalapana and Kaimū. Kaimū Bay and Kalapana Black Sand Beach were completely covered with lava. Over 100 homes were destroyed by the ever-broadening flow field in a nine-month period. New tubes diverted lava away from Kalapana early in 1991, lava once again entered the ocean within Hawaii Volcanoes National Park; the volume of lava erupted from Kūpaʻianahā declined through 1991, in early 1992, the vent died. The eruption returned to Puʻu ʻŌʻō, where flank vents on the west and southwest sides of the cone constructed a new lava shield. Soon lava tubes were feeding lava from the vents with few surface flows in between.
The flank vents have held center stage since, with the exception of a two-month pause in activity, early in 1997, which followed a brief fissure eruption in Nāpau Crater, a short distance southwest of Puʻu ʻŌʻō. On the evening of January 29, 1997, a series of earthquakes struck Kīlauea's east rift zone. Deep within the rift zone, magma was escaping from the conduit leading to the Puʻu ʻŌʻō vent, cutting off the supply to the ongoing eruption; the lava pond at Puʻu ʻŌʻō drained, residents 10 miles away heard a low, rumbling roar as the crater floor dropped 500 feet and the west wall of the Puʻu ʻŌʻō cone collapsed. A few hours as magma found a new path to the surface, the ground cracked in nearby Nāpau Crater, lava fountains lit up the night sky. However, activity in this area was short-lived, the center of activity soon shifted back to Puʻu ʻŌʻō; as of January 2007, 3.1 cubic km of lava had covered 117 km2 and added 201 hectares to Kīlauea's southern shore. The new shoreline was 15.6 km long.
The lava flows have destroyed 189 structures and covered 14 km of highway with as much as 35 m of lava. In 2007, after a cluster of earthquakes, activity in Puʻu ʻŌʻō subsided and the crater floor collapsed, with no incandescence visible in the crater after the end of August. Lava began emerging from a series of cracks in the northeast rift zone and spread east and south as a perched flow, with slow advances of ʻaʻā; the flow spread over flows of 1983–1986, with minor incursions into adjoining forests. In late July 2008, additional flows extended from the eastern vents of Puʻu ʻŌʻō and in October multiple new fissures opened along the length of the tube expanding into Royal Gardens Subdivision and covered a large area of the coastal flats in November 2008. On March 5, 2011, the floor of the Puʻu ʻŌʻō crater deflated collapsed. Two hours a new eruption occurred in Kīlauea's middle east zone, between Puʻu ʻŌʻō and Napau Crater. Lava fountains were reported to be 65 feet high. On March 26, 2011, lava began being visible in USGS HVO webcam.
The USGS stated that the accumulation of lava had put the crater floor about 39 m below the eastern crater rim, as of June 1. On September 21, 2011, lava in the west lava lake in Puʻu ʻŌʻō Crater fed a series of lava flows that traveled down the west flank of Puʻu ʻŌʻō during September
Midway Atoll is a 2.4-square-mile atoll in the North Pacific Ocean at 28°12′N 177°21′W. Midway is equidistant between North America and Asia. Midway Atoll is an unincorporated territory of the United States. Midway continues to be the only island in the Hawaiian archipelago, not part of the state of Hawaii. Unlike the other Hawaiian islands, Midway observes Samoa Time, one hour behind the time in the state of Hawaii. For statistical purposes, Midway is grouped as one of the United States Minor Outlying Islands; the Midway Atoll National Wildlife Refuge, encompassing 590,991.50 acres of land and water in the surrounding area, is administered by the United States Fish and Wildlife Service. The refuge and most of its surrounding area are part of the larger Papahānaumokuākea Marine National Monument; until 1993, the atoll was the home of the Naval Air Facility Midway Island. The Battle of Midway, fought between June 4 and 6, 1942, was a critical Allied victory of the Pacific campaign of World War II.
The United States Navy defended the atoll from a Japanese invasion, defeating a Japanese battle group, marking a turning point in the war in the Pacific Theater. USAAF aircraft based at the original Henderson Field on Eastern Island joined the attack against the Japanese fleet, which suffered losses of four carriers and one heavy cruiser. 40 to 60 people live on the atoll, which includes staff of the U. S. Fish and Wildlife Service and contract workers. Visitation to the atoll is possible only for business reasons as the tourism program has been suspended due to budget cutbacks. In 2012, the last year that the visitor program was in operation, 332 people made the trip to Midway. Tours focused on both the unique ecology of Midway as well as its military history; the economy is derived from governmental sources and tourist fees. Nearly all supplies must be brought to the island by ship or plane, though a hydroponic greenhouse and garden supply some fresh fruits and vegetables; as its name suggests, Midway is equidistant between North America and Asia, lies halfway around the world longitudinally from Greenwich, UK.
It is near the northwestern end of the Hawaiian archipelago, about one-third of the way from Honolulu, Hawaii, to Tokyo, Japan. Midway island is not considered part of the State of Hawaii due to the passage of the Hawaii Organic Act, which formally annexed Hawaii to the United States as a territory, only defined Hawaii as "the islands acquired by the United States of America under an Act of Congress entitled'Joint resolution to provide for annexing the Hawaiian Islands to the United States,' approved July seventh, eighteen hundred and ninety-eight." Although it could be argued that Midway became part of Hawaii when Middlebrooks discovered it in 1859, it was assumed at the time that Midway was independently acquired by the U. S. when Reynolds visited in 1867, so was not considered part of the Territory. In defining which islands the State of Hawaii would inherit from the Territory, the Hawaii Admissions Act clarified the question excluding Midway from the jurisdiction of the state. Midway Atoll is 140 nautical miles east of the International Date Line, about 2,800 nautical miles west of San Francisco, 2,200 nautical miles east of Tokyo.
Midway Atoll is part of a chain of volcanic islands and seamounts extending from Hawaii up to the tip of the Aleutian Islands and known as the Hawaiian–Emperor seamount chain. It consists of a ring-shaped barrier reef nearly five miles in diameter and several sand islets; the two significant pieces of land, Sand Island and Eastern Island, provide a habitat for millions of seabirds. The island sizes are shown in the table above; the atoll, which has a small population, is designated an insular area under the authority of the United States Department of the Interior. Midway was formed 28 million years ago when the seabed underneath it was over the same hotspot from which the Island of Hawaii is now being formed. In fact, Midway was once a shield volcano as large as the island of Lana'i; as the volcano piled up lava flows building the island, its weight depressed the crust and the island subsided over a period of millions of years, a process known as isostatic adjustment. As the island subsided, a coral reef around the former volcanic island was able to maintain itself near sea level by growing upwards.
That reef is now over 516 feet thick. What remains today is a shallow water atoll about 6 miles across. Following Kure Atoll, Midway is the 2nd most northerly atoll in the world; the atoll has some 20 miles of roads, 4.8 miles of pipelines, one port on Sand Island, an airfield. As of 2004, Henderson Field airfield at Midway Atoll, with its one active runway has been designated as an emergency diversion airport for aircraft flying under ETOPS rules. Although the FWS closed all airport operations on November 22, 2004, public access to the island was restored from March 2008. Eastern Island Airstrip is a disused airfield, in use by U. S. forces during the
Haleakalā, or the East Maui Volcano, is a massive shield volcano that forms more than 75% of the Hawaiian Island of Maui. The western 25% of the island is formed by another volcano, Mauna Kahalawai referred to as the West Maui Mountains; the tallest peak of Haleakalā, at 10,023 feet, is Puʻu ʻUlaʻula. From the summit one looks down into a massive depression some 11.25 km across, 3.2 km wide, nearly 800 m deep. The surrounding walls are steep and the interior barren-looking with a scattering of volcanic cones. Early Hawaiians applied the name Haleakalā to the general mountain. Haleakalā is the name of a peak on the southwestern edge of Kaupō Gap. In Hawaiian folklore, the depression at the summit of Haleakalā was home to the grandmother of the demigod Māui. According to the legend, Māui's grandmother helped him capture the sun and force it to slow its journey across the sky in order to lengthen the day. According to the United States Geological Survey USGS Volcano Warning Scheme for the United States, the Volcano Alert Level for Haleakala as of August 2015 was "normal".
A Normal status is used to designate typical volcanic activity in a non-eruptive phase. Haleakala has produced numerous eruptions including in the last 500 years; this volcanic activity has been along two rift zones: east. These two rift zones together form an arc that extends from La Perouse Bay on the southwest, through the Haleakalā Crater, to Hāna to the east; the east rift zone continues under the ocean beyond the east coast of Maui as Haleakalā Ridge, making the combined rift zones one of the longest in the Hawaiian Islands chain. Until East Maui Volcano was thought to have last erupted around 1790, based on comparisons of maps made during the voyages of La Perouse and George Vancouver. Recent advanced dating tests, have shown that the last eruption was more to have been in the 17th century; these last flows from the southwest rift zone of Haleakalā make up the large lava deposits of the Ahihi Kina`u/La Perouse Bay area of South Maui. Contrary to popular belief, Haleakalā crater is not volcanic in origin, nor can it be called a caldera.
Scientists believe that Haleakalā's crater was formed when the headwalls of two large erosional valleys merged at the summit of the volcano. These valleys formed the two large gaps — Koʻolau on the north side and Kaupō on the south — on either side of the depression. Macdonald, Abbott, & Peterson state it this way: Haleakalā is far smaller than many volcanic craters. On the island of Hawaiʻi, lava-flow hazards are rated on a scale of one through nine with one being the zone of highest hazard and nine being the zone of lowest hazard. For example, the summits and rift zones of Kilauea and Mauna Loa volcanoes are rated Hazard Zone 1. Using this same scale, preliminary estimates of lava-flow hazard zones on Maui made in 1983 by the U. S. Geological Survey rated the summit and southwest rift zone of Haleakala as Hazard Zone 3; the steep, downslope areas of the Kanaio and Kahikinui ahupuaʻa and the area north of Hana are rated as Hazard Zone 4. Other areas of Haleakala are rated comparable to the lava-flow hazards of Mauna Kohala.
These high hazard estimates for Haleakala are based on the frequency of its eruptions. Haleakala has erupted three times in the last 900 years. By way of comparison, both Mauna Loa and Kilauea have erupted more than a dozen times each in the last 90 years. Hualalai has an eruption rate comparable to Haleakala. All of Hualalai is rated as Hazard Zone 4. However, the frequency of eruption of a volcano is only one of the criteria on which hazards are based; the other important criterion is the lava flow coverage rate. Using the preliminary dates for Haleakala flows, only 8.7 square miles of lava flows have been emplaced in the last 900 years. In comparison 43 square miles of Hualalai are covered with flows 900 years old or younger and 104 square miles on Kilauea and 85 square miles on Mauna Loa are covered by lavas less than 200 years old. Thus, Haleakala is a distant fourth in coverage rates. Surrounding and including the crater is Haleakalā National Park, a 30,183-acre park, of which 24,719 acres are wilderness.
The park includes the summit depression, Kipahulu Valley on the southeast, ʻOheʻo Gulch, extending to the shoreline in the Kipahulu area. From the summit, there are two main trails leading into Haleakalā: Sliding Sands Trail and Halemauʻu Trail; the temperature near the summit tends to vary between about 40 °F and 60 °F and given the thin air and the possibility of dehydration at that elevation, the walking trails can be more challenging than one might expect. This is aggravated by the fact; because of this, hikers are faced with a difficult return ascent after descending 2000 ft or more to the crater floor. Despite this, Haleakalā is popular with tourists and locals alike, who venture to its summit, or to the visitor center just below the summit, to view the sunrise. There is lodging in the form of a few simple cabins, though no gas is available in the park; because of the remarkable clarity and stillness of the air, its elevation (with atmospheric pressure of 71 kilopascal
Kure Atoll or Ocean Island is an atoll in the Pacific Ocean 48 nautical miles beyond Midway Atoll in the Northwestern Hawaiian Islands at 28°25′N 178°20′W. The only land of significant size is called Green Island and is a habitat for hundreds of thousands of seabirds. A short and unmaintained runway and a portion of one building, both from a former United States Coast Guard LORAN station, are located on the island. Politically it is part of Hawaii, although separated from the rest of the state by Midway, a separate unorganized territory. Green Island, in addition to being the nesting grounds of tens of thousands of seabirds, has recorded several vagrant terrestrial birds including snow bunting, eyebrowed thrush, olive-backed pipit, black kite, Steller's sea eagle and Chinese sparrowhawk; the International Date Line lies 100 miles to the west. Although located to the west of Midway Atoll, Kure Atoll has a timezone +1 hour ahead at UTC−10:00. Kure is the northernmost coral atoll in the world, it consists of a 6-mile wide nearly circular barrier reef surrounding a shallow lagoon and several sand islets.
There is a total land area of 213.097 acres, with Green Island on the southeast side having 191.964 acres of this total. A growing number of Hawaiian monk seals haul out on its beaches. Data chart below has been taken from Midway Atoll due to a lack of any weather stations present on Kure Atoll. Kure Atoll features a tropical savanna climate with high year-round temperatures. Rainfall is evenly distributed throughout the year, with only two months being able to be classified as dry season months; the geological history of Kure is similar to Midway, but Kure lies close to what is called the Darwin Point, the latitude at which reef growth just equals reef destruction by various physical forces. As Kure continues to be carried along to the northwest by the motion of the Pacific Plate, it will move into waters too cool for coral and coralline algae growth to keep up with isostatic subsidence of the mountain, so long as global warming does not interfere; the atoll is warmed by the pools of water at the ends of the warm Kuroshio Current, keeping it in comfortable range in winter.
Barring unforeseen evolution, it will begin to join the other volcanic and reef-topped remnants of the Hawaiian–Emperor seamount chain to the northwest, all of which are now seamounts. In the Hawaiian language the term Mokupāpapa was used for any flat island with reefs; the northwestern islands are associated with Kāne Milohai in Hawaiian mythology. The brother of Pele was left to stand guard for travelers. Before the mid-19th century, Kure Atoll was given new names each time. Sometimes spelled Cure, its English name was for a Russian navigator, it was named Kure Island in 1924 and Kure Atoll in 1987. Many crews were stranded on Kure Atoll after being shipwrecked on the surrounding reefs and had to survive on the local seals and birds; the shipwrecks remain on the reef today, including the USS Saginaw. Because of these incidents, King Kalākaua sent Colonel J. H. Boyd to Kure as his Special Commissioner. On September 20, 1886, he took possession of the island for the Hawaiian government; the King ordered that a crude house be built on the island, with tanks for holding water and provisions for any other unfortunates who might be cast away there.
But the provisions were stolen within a year and the house soon fell into ruins. Neglected for most of its history, during World War II Kure was visited by U. S. Navy patrols from nearby Midway to ensure that the Japanese were not using it to refuel submarines or flying boats from submarine-tankers for attacks elsewhere in the Hawaiian chain. During the Battle of Midway, a Japanese Nakajima B5N "Kate" bomber, operating from aircraft carrier Hiryū, piloted by Lieutenant Kikuchi Rokurō, and, involved in the initial Japanese attack on Midway's US installations, crash-landed near Kure after being damaged by US fighters. Once ashore, Lt. Kikuchi and the two other members of his crew refused capture and were either killed or committed suicide when an American landing party tried to capture them. Kure is located within a major current which washes up debris from the Great Pacific garbage patch, such as fishing nets and large numbers of cigarette lighters, on the island; these pose threats to the local animals birds, whose skeletons are found with plastic in the stomach cavity.
On October 16, 1998, the longline fishing vessel Paradise Queen II ran aground on the eastern edge of Green Island of Kure Atoll, spilling 4,000 gallons of diesel fuel before recovery operations could commence. Debris from that shipwreck continued to pollute the reef and shoreline for many years, endangering wildlife and damaging the coral reef; the long-term impact of this and other wrecks within the Northwestern Hawaiian Islands highlight the dangers to sensitive habitats in the area. To help ensure their protection, the Papahānaumokuākea Marine National Monument was designated a Particularly Sensitive Sea Area in 2008 by the International Maritime Organization. In addition to avoiding specific areas, owners must identify when their ship enters and leaves the PSSA's 10 nautical mile wide reporting area so a timely response can be taken should there be a maritime emergency. From 1960 to 1992, a United States Coast Guard LORAN station was located on Green Island. A short coral runway was built on the is