Phreatic eruption

Information about Phreatic eruption

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Phreatic eruption at the summit of Mount St. Helens, Washington.
Phreatic eruptions, also called ultravulcanian eruptions, occur when rising magma makes contact with ground or surface water. The extreme temperature of the magma (anywhere from 600 Â°C to 1,170 Â°C (1110–2140 Â°F)) causes near-instantaneous evaporation to steam resulting in an explosion of steam, water, ash, rock, and volcanic bombs. At Mount St. Helens hundreds of steam explosions preceded a 1980 plinian eruption of the volcano. A less intense geothermal event may result in a mud volcano. In 1949, Thomas Jaggar described this kind of activity as steam-blast eruptions.

Phreatic eruptions typically include steam and rock fragments; the inclusion of lava is unusual. The temperature of the fragments can range from cold to incandescent. If molten material is included, the term phreato-magmatic may be used. These eruptions occasionally create broad, low-relief craters called maar. Phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas emissions. The former can asphyxiate at sufficient concentration; the latter is a broad spectrum poison. A 1979 phreatic eruption on the island of Java killed 149 people, most of whom were overcome by poisonous gases.

It is believed the 1883 eruption of Krakatoa - which obliterated most of the volcanic island and created the loudest sound in recorded human history - was a phreatic event. Kilauea, in Hawaii, has a long record of phreatic explosions; a 1924 phreatic eruption hurled rocks estimated at eight tons up to a distance of one kilometer. Additional examples are the 1963–65 eruption of Surtsey, and the 1965 eruption of Taal Volcano.

References

Magma (Plurals: magmas and magmata) is molten rock located beneath the surface of the Earth (or any other terrestrial planet) that often collects in a magma chamber. Magma may contain suspended crystals and gas bubbles.
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Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water.
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In physical chemistry, and in engineering, steam refers to vaporized water. It is a pure, completely invisible gas (for mist see below). At standard atmospheric pressure, pure steam (unmixed with air, but in equilibrium with liquid water) occupies about 1,600 times the
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volcanic bomb is a globe of molten rock (tephra) larger than 65 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. They cool into solid fragments before they reach the ground.
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For the mountain in California, see .


Mount St. Helens is an active stratovolcano in Skamania County, Washington, in the Pacific Northwest region of the United States.
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Plinian eruptions are volcanic eruptions marked by their similarity to the eruption of Mt. Vesuvius in AD 79 (as described in a letter written by Pliny the Younger) that killed Pliny the Elder.
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Volcano:
1. Large magma chamber
2. Bedrock
3. Conduit (pipe)
4. Base
5. Sill
6. Branch pipe
7. Layers of ash emitted by the volcano
8. Flank 9. Layers of lava emitted by the volcano
10. Throat
11. Parasitic cone
12. Lava flow
13. Vent
14.
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geothermal refers to heat sources within the planet. Strictly speaking, geo-thermal necessarily refers to the Earth but the concept may be applied to other planets.

Geothermal is technically an adjective (e.g., geothermal energy) but in U.S.
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mud volcano or mud dome is used to refer to formations created by geologically excreted liquids and gases, although there are several different processes which may cause such activity. Temperatures are much cooler than igneous processes.
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Thomas A. Jaggar (1871-1953) was the founder and first Director of the Hawaiian Volcano Observatory. He was born in Philadelphia, Pennsylvania.

In 1897, he received his Ph.D. in geology from Harvard University. He spent the next few years as a scientist in the laboratory.
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The term phreatic is used in geology to refer to matters relating to ground water below the static water table (the word originates from the Greek phrear, phreat- meaning "well" or "spring"). "Phreatic surface" is a synonym for "water table.
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Incandescence is the release of thermal radiation from a body due to its temperature. The distribution of energy emissions across the electromagnetic spectrum is described by Planck's law; at temperatures occurring on Earth, the release of radiation is usually predominantly in the
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A volcanic crater is a conspicuous feature of many volcanoes, especially those currently or recently active. It is typically a basin of a roughly circular form within which occurs a vent (or vents) from which magma erupts as gases, lava, and ejecta.
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maar is a broad, low relief crater that is caused by a phreatic eruption or explosion caused by groundwater contact with hot lava or magma. The maar typically fills with water to form a relatively shallow crater lake.
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Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state.
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Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence.
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Asphyxia
Classification & external resources

ICD-10 R 09.0 , T 71.
ICD-9 799.0

“Suffocation” redirects here. For the death metal band, see Suffocation (band).

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Java
Native name: Jawa<nowiki />

Topography of Java

Geography
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Location Southeast Asia
Coordinates <nowiki />
Archipelago
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KRAKATOA is a modular explosive device used for explosive ordnance disposal (EOD) or demolitions. It was developed by the British company Alford Technologies and has been featured during the second season of Discovery Channel's Future Weapons television series.
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State of Hawaii
Mokuʻāina o Hawaiʻi

Flag of Hawaii Seal of Hawaii
Nickname(s): The Aloha State

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Surtsey (Icelandic: "Surtur's island") is a volcanic island off the southern coast of Iceland. At it is also the southernmost point of Iceland.
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Taal Volcano is an active volcano on the island of Luzon in the Philippines. This is located in Talisay and San Nicolas in Batangas. It consists of an island in Lake Taal, which is situated within a caldera formed by an earlier very large eruption.
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