|
VEI-8 Eruptions
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] |
