Volcanic ash

ashash cloudash fallash plumeash flowAsh layerash layersash-fallAshfallAshfalls
Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter.wikipedia
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Volcano

volcanicvolcanoesextinct volcano
Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter.
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.

Eruption column

ash columnash plumeplume
These are typically produced by lava dome collapse or collapse of the eruption column.
An eruption column is a cloud of super-heated ash and tephra suspended in gases emitted during an explosive volcanic eruption.

Explosive eruption

explosiveexplosive activityexplosive eruptions
The term volcanic ash is also often loosely used to refer to all explosive eruption products (correctly referred to as tephra), including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere.
Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent.

2010 eruptions of Eyjafjallajökull

Eyjafjallajökulleruption2010 eruption of Eyjafjallajökull
For example, the second phase of the 2010 eruptions of Eyjafjallajökull was classified as VEI 4 despite a modest 8 km high eruption column, but the eruption continued for a month, which allowed a large volume of ash to be ejected into the atmosphere. In April 2010 airspace all over Europe was affected, with many flights cancelled-which was unprecedented-due to the presence of volcanic ash in the upper atmosphere from the eruption of the Icelandic volcano Eyjafjallajökull.
The radar stations of the Meteorological Institute of Iceland did not detect any appreciable amount of volcanic ashfall during the first 24 hours of the eruption.

Tephra

pyroclasttephra layerpyroclastic
The term volcanic ash is also often loosely used to refer to all explosive eruption products (correctly referred to as tephra), including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere.
Ash – particles smaller than 2 mm (0.08 inches) in diameter

Volcanic Explosivity Index

VEIvolcanic explosivity index (VEI)VEI 5
Volcanoes display a range of eruption styles which are controlled by magma chemistry, crystal content, temperature and dissolved gases of the erupting magma and can be classified using the volcanic explosivity index (VEI).
Under the VEI, ash, lava, lava bombs, and ignimbrite are all treated alike.

Zeolite

zeoliteszeoliticdachiardite
Particle surfaces are often coated with aggregates of zeolite crystals or clay and only relict textures remain to identify pyroclast types.
Natural zeolites form where volcanic rocks and ash layers react with alkaline groundwater.

Hawaiian eruption

Hawaiianeffusiveeruptions
Ash produced during low viscosity magmatic eruptions (e.g., Hawaiian and Strombolian basaltic eruptions) produce a range of different pyroclasts dependent on the eruptive process.
Very small amounts of volcanic ash are produced.

Basalt

basalticcolumnar basaltbasalts
Effusive eruptions (VEI 1) of basaltic composition produce 10 9 m 3 ) of ejecta into the atmosphere.
Basalt that erupts under open air (that is, subaerially) forms three distinct types of lava or volcanic deposits: scoria; ash or cinder (breccia); and lava flows.

Lapilli

lapilli-tuffaccretionary lapillicinders
This is followed by fallout of accretionary lapilli, which is the result of particle agglomeration within the column.
Pyroclastic material with particles less than 2 mm in diameter is referred to as volcanic ash.

Air travel disruption after the 2010 Eyjafjallajökull eruption

air travel disruptiondisruption to air travelEyjafjallajökull eruption
In April 2010 airspace all over Europe was affected, with many flights cancelled-which was unprecedented-due to the presence of volcanic ash in the upper atmosphere from the eruption of the Icelandic volcano Eyjafjallajökull.
In response to concerns that volcanic ash ejected during the 2010 eruptions of Eyjafjallajökull in Iceland would damage aircraft engines, the controlled airspace of many European countries was closed to instrument flight rules traffic, resulting in the largest air-traffic shut-down since World War II. The closures caused millions of passengers to be stranded not only in Europe, but across the world.

British Airways Flight 9

Flight 9British Airways aircraftBritish Airways Flight
On 24 June 1982 a British Airways Boeing 747-236B (Flight 9) flew through the ash cloud from the eruption of Mount Galunggung, Indonesia resulting in the failure of all four engines.
The aircraft flew into a cloud of volcanic ash thrown up by the eruption of Mount Galunggung (approximately 110 mi south-east of Jakarta, Indonesia), resulting in the failure of all four engines.

Volcanic Ash Advisory Center

VAACVolcanic Ash Advisory CentreAnchorage Volcanic Ash Advisory Center
This information is passed between meteorological agencies, volcanic observatories and airline companies through Volcanic Ash Advisory Centers (VAAC).
A Volcanic Ash Advisory Center (VAAC) is a group of experts responsible for coordinating and disseminating information on atmospheric volcanic ash clouds that may endanger aviation.

KLM Flight 867

Flight 867
On 15 December 1989 a KLM Boeing 747-400 (Flight 867) also lost power to all four engines after flying into an ash cloud from Mount Redoubt, Alaska.
The Boeing 747-400 combi, less than six months old at the time, flew through a thick cloud of volcanic ash from Mount Redoubt, which had erupted the day before.

Strombolian eruption

strombolianStrombo-VulcanianStromboli
Ash produced during low viscosity magmatic eruptions (e.g., Hawaiian and Strombolian basaltic eruptions) produce a range of different pyroclasts dependent on the eruptive process.
Cinder is the most common product; the amount of volcanic ash is typically rather minor.

Mount Redoubt

Redoubt VolcanoMt. RedoubtRedoubt
On 15 December 1989 a KLM Boeing 747-400 (Flight 867) also lost power to all four engines after flying into an ash cloud from Mount Redoubt, Alaska.
The eruption in 1989 spewed volcanic ash to a height of 45,000 ft (14,000 m). It caught KLM Flight 867, a Boeing 747 aircraft, in its plume.

Mount Pinatubo

Mt. Pinatubo1991 eruption of Mount PinatuboPinatubo
In the 1990s a further US$100 million of damage was sustained by commercial aircraft (some in the air, others on the ground) as a consequence of the 1991 eruption of Mount Pinatubo in the Philippines.
Over the next few weeks, small eruptions continued, dusting the surrounding areas with volcanic ash.

Indonesia

🇮🇩IndonesianRepublic of Indonesia
On 24 June 1982 a British Airways Boeing 747-236B (Flight 9) flew through the ash cloud from the eruption of Mount Galunggung, Indonesia resulting in the failure of all four engines.
While volcanic ash has resulted in fertile soils (a factor in historically sustaining high population densities of Java and Bali), it makes agricultural conditions unpredictable in some areas.

Galunggung

Mount GalunggungEruption of Mt GalunggungGalunggung (Beuticanar)
On 24 June 1982 a British Airways Boeing 747-236B (Flight 9) flew through the ash cloud from the eruption of Mount Galunggung, Indonesia resulting in the failure of all four engines.
This eruption also brought the dangers of volcanic ash to aviation to worldwide attention, after two Boeing 747 passenger jets flying downwind of the eruption suffered temporary engine failures and damage to exterior surfaces, both planes being forced to make emergency landings at Jakarta airport.

Surtsey

Syrtlingur
Signal attenuation due to volcanic ash is not well documented; however, there have been reports of disrupted communications following the 1969 Surtsey eruption and 1991 Mount Pinatubo eruption.
The explosive phreatomagmatic eruptions caused by the easy access of water to the erupting vents threw rocks up to a kilometre (0.6 mi) away from the island, and sent ash clouds as high as 10 km up into the atmosphere.

Andisol

andisol soilsandisolslava soil
Once the minerals in ash are washed into the soil by rain or other natural processes, it mixes with the soil to create an andisol layer.
In USDA soil taxonomy, Andisols are soils formed in volcanic ash and defined as soils containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite.

Energetically modified cement

Energetically modified cement (EMC)
Energetically modified cements (EMC) are a class of cementitious materials made from pozzolans (e.g. fly ash, volcanic ash, pozzolana), silica sand, blast furnace slag, or Portland cement (or blends of these ingredients).

Types of volcanic eruptions

volcanic eruptioneruptionvolcanic eruptions
Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter.
Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists.

Volcanic ash and aviation safety

flying through volcano ashhazards
Volcanic ash and aviation safety
Plumes of volcanic ash near active volcanoes are a flight safety hazard, especially for night flights.

Mount Ruapehu

RuapehuMt Ruapehu1995/96 Mount Ruapehu eruptions
Following the 1995/96 Mount Ruapehu eruptions in New Zealand, two thousand ewes and lambs died after being affected by fluorosis while grazing on land with only 1–3 mm of ash fall.
Some of the minor eruptions in the 1970s generated small ash falls and lahars (mudflows) that damaged skifields.