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Keanakakoi Eruption
The Keanakakoi eruption was a VEI-4 eruption that occurred from the summit caldera of Kīlauea volcano in or around November 1790. It has been described as the deadliest volcanic eruption in what is now the United States, with more than 400 people having been killed in the event. The eruption deposited the Keanakakoi Ash which surrounds the Kīlauea Caldera. Three eruptive phases define the Keanakakoi eruption, all of which were separated by quiescent spells. The first phase was phreatomagmatic, and involved the deposition of fine-grained, well-bedded volcanic ash. A Strombolian-style scoria fall deposit and phreatomagmatic ash similar to that of the first phase were deposited during the second phase. The third and final phase was phreatic and produced interbedded pyroclastic fallout and surge deposits. See also *1790 Footprints The 1790 Footprints refer to a set of footprints found near the Kīlauea volcano in present-day Hawaii Volcanoes National Park on the island of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kaʻū Desert
The Kaū Desert is a leeward desert in the district of Kaū, the southernmost district on the Big Island of Hawaii, and is made up mostly of dried lava remnants, volcanic ash, sand and gravel. The desert covers an area of the Kīlauea Volcano along the Southwest rift zone. The area lacks any vegetation, mainly due to acid rainfall. Climate Kaū desert is not a true desert in that rainfall exceeds per year. However, rain combines with sulfur dioxide, released by volcanic vents, and forms acid rain. The pH level of the rain, as low as 3.4 during an eruption, inhibits plant growth. Furthermore, water evaporates quickly on the ground and the tephra soil is extremely permeable. Visiting The Kaū Desert is popular for walking and hiking tours during inactive periods. It can be reached by following Highway 11 counterclockwise from Kona to the volcano. The trailhead is on Crater Rim Drive, coordinates . By traversing the desert, one can cross the Great Crack and the Southwest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatomagmatic Eruption
Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts.Heiken, G. & Wohletz, K. 1985. Volcanic Ash. University of California Press, Berkeley It is common for a large explosive eruption to have magmatic and phreatomagmatic components. Mechanisms Several competing theories exist as to the exact mechanism of ash formation. The most common is the theory of explosive thermal contraction of particles under rapid cooling from contact with water. In many cases the water is supplied by the sea, for example with Surtsey. In other cases the water may be present in a lake or caldera-lake, for example Santorini, where the phreatomagmatic component of the Minoan eruption was a result of both a lake and later the sea. There have also been examples of interaction between magma a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatomagmatic Eruptions
Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts.Heiken, G. & Wohletz, K. 1985. Volcanic Ash. University of California Press, Berkeley It is common for a large explosive eruption to have magmatic and phreatomagmatic components. Mechanisms Several competing theories exist as to the exact mechanism of ash formation. The most common is the theory of explosive thermal contraction of particles under rapid cooling from contact with water. In many cases the water is supplied by the sea, for example with Surtsey. In other cases the water may be present in a lake or caldera-lake, for example Santorini, where the phreatomagmatic component of the Minoan eruption was a result of both a lake and later the sea. There have also been examples of interaction between magma a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Eruptions In The United States
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1790 In Hawaii
Year 179 ( CLXXIX) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Aurelius and Veru (or, less frequently, year 932 ''Ab urbe condita''). The denomination 179 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman empire * The Roman fort Castra Regina ("fortress by the Regen river") is built at Regensburg, on the right bank of the Danube in Germany. * Roman legionaries of Legio II ''Adiutrix'' engrave on the rock of the Trenčín Castle (Slovakia) the name of the town ''Laugaritio'', marking the northernmost point of Roman presence in that part of Europe. * Marcus Aurelius drives the Marcomanni over the Danube and reinforces the border. To repopulate and rebuild a devastated Pannonia, Rome allows the first German colonists to enter territory co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Disasters In Hawaii
Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are part of nature, human activity is often understood as a separate category from other natural phenomena. The word ''nature'' is borrowed from the Old French ''nature'' and is derived from the Latin word ''natura'', or "essential qualities, innate disposition", and in ancient times, literally meant "birth". In ancient philosophy, ''natura'' is mostly used as the Latin translation of the Greek word ''physis'' (φύσις), which originally related to the intrinsic characteristics of plants, animals, and other features of the world to develop of their own accord. The concept of nature as a whole, the physical universe, is one of several expansions of the original notion; it began with certain core applications of the word φύσις by pre-Socr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
18th-century Volcanic Events
The 18th century lasted from January 1, 1701 (Roman numerals, MDCCI) to December 31, 1800 (Roman numerals, MDCCC). During the 18th century, elements of Age of Enlightenment, Enlightenment thinking culminated in the American Revolution, American, French Revolution, French, and Haitian Revolution, Haitian Revolutions. During the century, History of slavery, slave trading and human trafficking expanded across the shores of the Atlantic Ocean, Atlantic, while declining in Russian Empire, Russia, Qing dynasty, China, and Joseon, Korea. Revolutions began to challenge the legitimacy of monarchical and aristocratic power structures, including the structures and beliefs that Proslavery, supported slavery. The Industrial Revolution began during mid-century, leading to radical changes in Society, human society and the Natural environment, environment. Western historians have occasionally defined the 18th century otherwise for the purposes of their work. For example, the "short" 18th cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1790 Footprints
The 1790 Footprints refer to a set of footprints found near the Kīlauea volcano in present-day Hawaii Volcanoes National Park on the island of Hawaii. Resulting from an unusually explosive eruption, they may be associated with a series of battles in the area in 1790. Background The 1782 Battle of Mokuōhai gave Kamehameha I control of the west and north sides of the island of Hawaii, but Keōua Kuahuula and his uncle Keawemauhili were able to escape. For a few years, while Kamehameha was occupied with Maui and the arrival of Europeans to Kona, Keōua ruled Kaū and Keawemauhili ruled Hilo. By 1790, Keawemauhili and Kamehameha had made peace. Keawemauhili aided Kamehameha's invasion of Maui that same year. This cooperation broke an agreement between Keawemauhili and Keōua. Keōua, angered, raided some of the lands of Kamehameha while he was in Maui at the Battle of Kepaniwai. Keōua then attacked and killed his uncle at Hilo. Kamehameha returned from Maui to the Big Isla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Surge
A pyroclastic surge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes it more turbulent and allows it to rise over ridges and hills rather than always travel downhill as pyroclastic flows do. The speed of pyroclastic density currents has been measured directly via photography only in the case of Mount St. Helens, where they reached 320-470 km/h, or . Estimates of other modern eruptions are around 360 km/h, or 100 m/s (225 mph). Pyroclastic flows may generate surges. For example, the city of Saint-Pierre in Martinique in 1902 was overcome by one. Pyroclastic surge include 3 types, which are base surge, ash-cloud surge, and ground surge. Base surge First recognized after the Taal Volcano eruption of 1965 in the Philippines, where a visiting volcanologist from USGS recognized the pheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Fall
A pyroclastic fall is a uniform deposit of material which has been ejected from a volcanic eruption or plume such as an ash fall or tuff. Pyroclastic air fall deposits are a result of: # Ballistic transport of ejecta such as volcanic blocks, volcanic bombs and lapilli from volcanic explosions # Deposition of material from convective clouds associated with pyroclastic flows such as coignimbrite falls # Ejecta carried in gas streaming from a vent. The material under the action of gravity will settle out from an eruption plume or eruption column #Ejecta settling from an eruptive plume or eruption column that is displaced laterally by wind currents and is dispersed over great distances Structures The deposits of pyroclastic falls follow a well sorted and well bedded trend. They exhibit mantle bedding—the deposits directly overlie pre-existing topography and maintain a uniform thickness over relatively short distances. Sorting by size is more pronounced than pyroclastic surge or py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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