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Unzen
is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island. In 1792, the collapse of one of its several lava domes triggered a megatsunami that killed 14,524 people in Japan's worst volcanic-related disaster. The volcano was most recently active from 1990 to 1995, and a large eruption in 1991 generated a pyroclastic flow that killed 43 people, including three volcanologists. Its highest peaks are at and at . The latter emerged during the eruptions of the early, eponymous Heisei era (1989–2019). Overview Mount Unzen (or ) rises in the central part of the Shimabara Peninsula, Nagasaki Prefecture. It is located on the outer ring of the Chijiwa Caldera centering on Tachibana Bay in the west of the peninsula. It consists of a total of more than 20 mountains, however, the complexity in the shape of was expressed by various numbers (such as Mitake Goho/Mimine Godake as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unzen Volacno Relief Map, SRTM-1
is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island. In 1792, the collapse of one of its several lava domes triggered a megatsunami that killed 14,524 people in Japan's worst volcanic-related disaster. The volcano was most recently active from 1990 to 1995, and a large eruption in 1991 generated a pyroclastic flow that killed 43 people, including three volcanologists. Its highest peaks are at and at . The latter emerged during the eruptions of the early, eponymous Heisei era (1989–2019). Overview Mount Unzen (or ) rises in the central part of the Shimabara Peninsula, Nagasaki Prefecture. It is located on the outer ring of the Chijiwa Caldera centering on Tachibana Bay in the west of the peninsula. It consists of a total of more than 20 mountains, however, the complexity in the shape of was expressed by various numbers (such as Mitake Goho/Mimine Godake as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unzen Volcano
is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island. In 1792, the collapse of one of its several lava domes triggered a megatsunami that killed 14,524 people in Japan's worst volcanic-related disaster. The volcano was most recently active from 1990 to 1995, and a large eruption in 1991 generated a pyroclastic flow that killed 43 people, including three volcanologists. Its highest peaks are at and at . The latter emerged during the eruptions of the early, eponymous Heisei era (1989–2019). Overview Mount Unzen (or ) rises in the central part of the Shimabara Peninsula, Nagasaki Prefecture. It is located on the outer ring of the Chijiwa Caldera centering on Tachibana Bay in the west of the peninsula. It consists of a total of more than 20 mountains, however, the complexity in the shape of was expressed by various numbers (such as Mitake Goho/Mimine Godake as "24 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1792 Unzen Earthquake And Tsunami
The 1792 Unzen earthquake and tsunami resulted from the volcanic activities of Mount Unzen (in the Shimabara Peninsula of Nagasaki Prefecture, Japan) on 21 May. This caused the collapse of the southern flank of the Mayuyama dome in front of Mount Unzen, resulting in a tremendous megatsunami, killing 15,000 people altogether. It was also called , (Shimabara means the central mountain of the Shimabara Peninsula) since many people were killed by this tsunami in Higo (Kumamoto Prefecture, situated across the Ariake Sea). Volcanic activities Towards the end of 1791, a series of earthquakes occurred on the western flank of Mount Unzen which gradually moved towards Fugen-dake (one of Mount Unzen's peaks). In February 1792, Fugen-dake started to erupt, triggering a lava flow which continued for two months. Meanwhile, the earthquakes continued, shifting nearer to the city of Shimabara. On the night of 21 May, two large earthquakes were followed by a collapse of the eastern flank of Mount ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shimabara Peninsula
is a peninsula located in Nagasaki Prefecture on the island of Kyushu, Japan. The peninsula incorporates the cities of Shimabara, Minamishimabara, Unzen. It was also the site of the Shimabara Rebellion, a 1637-1638 peasant and rōnin revolt, led by Christians. This further reinforced distrust of Christians and foreigners by Shōgun Iemitsu and contributed to the 1639 decision to isolate Japan from the outside world. From then on, the Dutch and the Chinese were the only ones permitted to enter Japan through Nagasaki in a very limited fashion until Japan was reopened again.Hane, Modern Japan: A Historical Survey, p. 24 Administrative region *Eastern section of Isahaya * Shimabara *Minamishimabara *Unzen is an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island. In 1792, the collapse of one of its several lava domes triggered a megatsu ... References La ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratovolcano
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as . Stratovolcanoes are sometimes called composite volcanoes because of their composite stratified structure, built up from sequential outpourings of erupted materials. They are among the most common types of volcanoes, in contrast to the less common shield volca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megatsunami
A megatsunami is a very large wave created by a large, sudden displacement of material into a body of water. Megatsunamis have quite different features from ordinary tsunamis. Ordinary tsunamis are caused by underwater tectonic activity (movement of the earth's plates) and therefore occur along plate boundaries and as a result of earthquakes and the subsequent rise or fall in the sea floor that displaces a volume of water. Ordinary tsunamis exhibit shallow waves in the deep waters of the open ocean that increase dramatically in height upon approaching land to a maximum run-up height of around in the cases of the most powerful earthquakes. By contrast, megatsunamis occur when a large amount of material suddenly falls into water or anywhere near water (such as via a meteor impact or volcanic activity). They can have extremely large initial wave heights ranging from hundreds and possibly up to thousands of metres, far beyond the height of any ordinary tsunami. These giant wave hei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shimabara, Nagasaki
is a city located on the north-eastern tip of the Shimabara Peninsula, facing Ariake Bay in the east and Mount Unzen (including Fugendake) in the west, in Nagasaki Prefecture, Kyushu, Japan. As of October 1, 2016, the city has an estimated population of 44,936 and a population density of 540 per km². The total area is 82.77 km². Economy Shimabara is a popular tourist destination, due to its historical associations, location in Unzen-Amakusa National Park, and numerous ''onsen''. The most popular tourist destination within the urban area is Shimabara Castle and the nearby "''Samurai'' Street". The city has so much natural spring water, both hot and cold, that it runs through the streets. On Carp Street, koi swim in the canals. Principal agricultural products include mandarin oranges, tea, and tobacco. History Shimabara is a castle town, which was the capital of Shimabara Domain during the Edo period. It was the site of considerable foreign trade and missionary activity dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ariake Bay
The is a body of salt water surrounded by Fukuoka, Saga, Nagasaki, and Kumamoto Prefectures, all of which lie on the island of Kyūshū in Japan. It is the largest bay in Kyūshū. Its deepest point is only about 50 meters (165 ft) deep, and extreme tides exceed , covering roughly . Isahaya Bay is a branch of the Ariake Sea. Across the Amakusa Islands lies the Yatsushiro Sea. Many harbors are located on the coast of the Ariake Sea. Among them are Misumi (in the city of Uki, Kumamoto Prefecture), Shimabara (Shimabara, Nagasaki), Taira (Unzen, Nagasaki), Nagasu (Nagasu, Kumamoto), Kumamoto (Kumamoto, Kumamoto), Miike ( Omuta, Fukuoka), Kuchinotsu (Minamishimabara, Nagasaki), and Oniike (Amakusa, Kumamoto). Five ferry routes cross the Ariake Sea. Various species of fauna, including mudskippers, pen shells (''Atrina pectinata''), and fiddler crabs, live in the Ariake Sea. In autumn, the ''Suaeda'' halophyte ''shichimenso'' (''Suaeda japonica'') grows along the shore. The Ariake Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanologist
A volcanologist, or volcano scientist, is a geologist who focuses on understanding the formation and eruptive activity of volcanoes. Volcanologists frequently visit volcanoes, sometimes active ones, to observe and monitor volcanic eruptions, collect eruptive products including tephra (such as ash or pumice), rock and lava samples. One major focus of inquiry in recent times is the prediction of eruptions to alleviate the impact on surrounding populations and monitor natural hazards associated with volcanic activity. Geologists who research volcanic materials that make up the solid Earth are referred to as igneous petrologists. Etymology The word ''volcanologist'' (or ''vulcanologist'') is derived from the English volcanology (volcano + -logy), which was derived from the French volcanologie (or vulcanologie), which was further derived from the French word volcan (volcano), which was even further derived from Vulcanus, the Latin name of the Roman god of fire and metalworking. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graben
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic context by Eduard Suess in 1883. The plural form is either ''graben'' or ''grabens''. Formation A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side by side with horsts. Horst and graben structures indicate tensional forces and crustal stretching. Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of the horst. Single or multiple graben can produce a rift valley. Half-g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Flow
A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of but is capable of reaching speeds up to . The gases and tephra can reach temperatures of about . Pyroclastic flows are the most deadly of all volcanic hazards and are produced as a result of certain explosive eruptions; they normally touch the ground and hurtle downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope. Origin of term The word ''pyroclast'' is derived from the Greek (''pýr''), meaning "fire", and (''klastós''), meaning "broken in pieces". A name for pyroclastic flows which glow red in the dark is (French, "burning cloud"); this was notably used to describe the disastrous 1902 eruption of Mount Pelée on Martinique, a French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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