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Volcanic Explosivity Index
The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal") are used to determine the explosivity value. The scale is open-ended with the largest eruptions in history given a magnitude of 8. A value of 0 is given for non-explosive eruptions, defined as less than of tephra ejected; and 8 representing a supervolcanic eruption that can eject (240 cubic miles) of tephra and have a cloud column height of over . The scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, with the exception of between VEI-0, VEI-1 and VEI-2. Classification With indices running from 0 to 8, the VEI associated with an eruption is dependent on how much volcanic materia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strombolian Eruption
In volcanology, a Strombolian eruption is a type of volcanic eruption with relatively mild blasts, typically having a Volcanic Explosivity Index of 1 or 2. Strombolian eruptions consist of ejection of incandescent Scoria, cinders, lapilli, and volcanic bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence. This type of eruption is named for the Italy, Italian volcano Stromboli. The tephra typically glows red when leaving the vent, but its surface cools and assumes a dark to black colour and may significantly solidify before impact. The tephra accumulates in the vicinity of the vent, forming a cinder cone. Cinder is the most common product; the amount of volcanic ash is typically rather minor. The lava flows are more viscous, and therefore shorter and thicker, than the corresponding Hawaiian Eruption, Hawaiian eruptions; it may or may not be accompanied by production of pyroclastic rock. Instead the gas coale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1888 Ritter Island Eruption And Tsunami
On 13 March 1888, a section of Ritter Island, a small volcanic island off the coast of New Guinea, collapsed into the sea in a sector collapse. The collapse triggered tsunami waves that struck nearby and distant islands such as New Guinea, Umboi, Sakar and New Britain. It caused heavy damage and deaths in coastal settlements. While no confirmed death toll exists, it is estimated that between 1,500 and 3,000 people died. Background Ritter Island in the Bismarck Archipelago is an active stratovolcano located off the northeast coast of Papua New Guinea. It is one of the many active volcanoes in Papua New Guinea as a result of subduction of the Solomon Sea plate beneath the Bismarck Plate along the New Britain Trench. Before the eruption of 1888, the island was a steep-sided and almost-circular volcanic cone which was recognisable to sailors passing through the Dampier Strait (Papua New Guinea), Dampier Strait. It had an estimated height of . Based on sketches from the 1830s, the si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ritter Island
Ritter Island is a small crescent-shaped volcanic island north-east of New Guinea, situated between Umboi Island and Sakar Island. There are several recorded eruptions of this basaltic-andesitic stratovolcano prior to a spectacular lateral collapse which took place in 1888. Before that event, it was a circular conical island about high. 1888 eruption At about 5:30 am local time on 13 March 1888 a large portion of the island, containing perhaps of material slid into the sea during a relatively minor, possibly VEI 2, phreatic eruption. Eyewitnesses at Finschhafen, to the south, heard explosions and observed an almost imperceptible ash fall. Tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...s high were generated by the collapse and devastated nearby islands and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1792 Unzen Earthquake And Tsunami
The 1792 Unzen landslide 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 tsunami, 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 Unzen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount 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] |
Stromboli
Stromboli ( , ; ) is an island in the Tyrrhenian Sea, off the north coast of Sicily, containing Mount Stromboli, one of the four active volcanoes in Italy. It is one of the seven Aeolian Islands, a volcanic arc north of Sicily, and the mythological home of Aeolus. The island, with an area of , represents the upper third of the volcano. Its population was about 500 . The volcano has erupted many times and is constantly active with minor eruptions, often visible from many points on the island and from the surrounding sea, giving rise to the island's nickname "Lighthouse of the Mediterranean". Etymology The name Stromboli is derived from the Ancient Greek name , () which was derived from (, 'round'), after the volcano's round, conical appearance when seen from a distance. Height and shape Stromboli stands above sea level, and over above the sea floor. The area of Stromboli island is . As of June 2024, there are two active craters at the peak, each with multiple vents show ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Etna
Mount Etna, or simply Etna ( or ; , or ; ; or ), is an active stratovolcano on the east coast of Sicily, Italy, in the Metropolitan City of Catania, between the cities of Messina, Italy, Messina and Catania. It is located above the Convergent boundary, convergent plate margin between the African Plate and the Eurasian Plate. It is one of the tallest active volcanoes in Europe, and the tallest peak in Italy south of the Alps with a current height (September 2024) of , though this varies with summit eruptions. For instance, in 2021 the southeastern crater reached a height of , but was then surpassed by the Voragine crater after the summer 2024 eruptions. Etna covers an area of with a basal circumference of . This makes it by far the largest of the three volcanism in Italy, active volcanoes in Italy, being about two and a half times the height of the next largest, Mount Vesuvius. Only Teide, Mount Teide on Tenerife in the Canary Islands surpasses it in the whole of the Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulcanian Eruption
A Vulcanian eruption is a type of volcanic eruption characterized by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak. They usually commence with phreatomagmatic eruptions which can be extremely noisy due to the rising magma heating water in the ground. This is usually followed by the explosive clearing of the vent and the eruption column is dirty grey to black as old weathered rocks are blasted out of the vent. As the vent clears, further ash clouds become grey-white and creamy in colour, with convolutions of the ash similar to those of Plinian eruptions. The term ''Vulcanian'' was first used by Giuseppe Mercalli, witnessing the 1888–1890 eruptions on the island of Vulcano. His description of the eruption style is now used all over the world. Mercalli described Vulcanian eruptions as "...Explosions like cannon fire at irregular intervals..." Their explosive nature is due to increased silica content of the magma. Almost all types of magm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
:Category:VEI-2 Volcanoes
Volcanoes that have produced explosive VEI-2 eruptions. Such eruptions release a tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ... volume of at least with noticeable effects on the surrounding area. For smaller volcanoes that have erupted at less than of tephra at a time, see :VEI-1 volcanoes. For larger volcanoes that have erupted at least {{Convert, 0.01, km3, mi3, abbr=on of tephra at a time, see :VEI-3 volcanoes. Volcanoes by highest known Volcanic Explosivity Index of eruption ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2023–2025 Sundhnúkur Eruptions
The 2023–2025 Sundhnúkur eruptions () are a series of volcanic eruptions on the Southern Peninsula (Iceland), Reykjanes Peninsula, near the town of Grindavík, Iceland. Between December 2023 and April 2025, there have been eight eruptions, following an intense series of earthquakes in November 2023. Although localised, the seismic and volcanic activity have caused significant disruption across the western part of the peninsula, especially for the town of Grindavík. However, the Capital Region (Iceland), Capital Region, including Reykjavík, has remained physically unaffected. The eruptions were preceded by an intense earthquake swarm in the Eldvörp–Svartsengi, Eldvörp–Svartsengi volcanic system that began on 24 October 2023, caused by a Igneous intrusion, magmatic intrusion underneath the area. The frequency and intensity of the earthquakes dramatically increased on 10 November 2023, with around 20,000 tremors recorded by that time, the largest of which exceeded Richter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2012 Kermadec Islands Eruption
The 2012 Kermadec Islands eruption was a major undersea volcanic eruption that was produced by the previously little-known Havre Seamount near the L'Esperance and L'Havre Rocks in the Kermadec Islands of New Zealand. The large volume of low density pumice produced by the eruption accumulated as a large area of floating pumice, a ''pumice raft,'' that was originally covering a surface of , spread to a continuous float of between and within three months dispersed to an area of more than twice the size of New Zealand.Website of the expedition ''Mesh'' The thickness of the raft may initially have been as high as and was reduced to around within a month. Three months after the eruption, the mass had dispersed into very dilute rafts and ribbons of floating pumice clasts. Most pumice clasts became waterlogged and sank to the sea floor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
