Volcanic Ash

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volcanic ash

[väl′kan·ik ′ash]
Fine pyroclastic material; particle diameter is less than 4 millimeters.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Volcanic Ash


an incorrect but widespread name for a product of the natural pulverization of magma; it consists of a mixture of dust and sand, with a particle size less than 2 mm. Admixtures of foreign rocks are characteristic. It occurs as a result of the atomization of liquid or solid lavas of various compositions.

Depending on the size of the particles, the force of the eruption, and the wind, volcanic ash can settle at significant distances from the place of the eruption. Thus, for example, during the explosion of Bezymiannyi Volcano (on Kamchatka) in 1956, ash floated as far as Great Britain, and during the explosion of Krakatoa (Indonesia) in 1883, the smallest volcanic dust particles floated almost twice around the world.

Volcanic ash is used to make light concretes, glass for containers, cement, thermal-insulation material, and filtration material. It is also used as a medium for growing plants.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
In April and May 2010, the eruption of Eyjafallajokull volcano caused a giant ash cloud that sent shockwaves across the world and grounded most of European air travel.
The Federal Aviation Administration and the airline industry become concerned for trans-Pacific flights when an ash cloud has the potential to exceed 20,000 feet (6,100 meters).
At least six international flights from Perth to Denpasar, Indonesia, have been cancelled due to the ongoing effects of the volcanic ash cloud since the eruption of an Indonesian volcano on Friday.
Scientists at the observatory said the ash cloud was drifting at approximately 15,000 ft and was approximately 80 KM/50 miles moving ESE from the volcano.
The easyJet testing technology makes it feasible for pilots to identify an ash cloud ahead at altitudes between 5,000 and 50,000ftr Prata told the Guardian that AVOID uses 'two fast-sampling thermal infrared cameras' that make images of anything that is in front of the aircraft.
Virgin said the figure was achieved despite the ash cloud crisis costing the airline pounds 40m.
Australian officials said the ash cloud had travelled more than 2,500 miles in 24 hours and had been driven across southeastern Australia by strong southerly winds.
Dabbas pointed out that the airline formed a committee to follow the ash cloud movement that is slowly being pushed by the wind towards Sudan and the northwestern regions,
Contrary to their stance last week, Virgin spokesman Colin Lippiatt says the airline has been advised it is not safe to fly underneath the ash cloud, according to ABC News.
Meanwhile, airlines continue to disagree over the safety risk posed by the volcanic ash cloud to the south of Australia.
By Tesfa-Alem Tekle June 14, 2011 (ADDIS ABABA) -- Ethiopian Airlines has temporarily cancelled some domestic flights and international routes destined to neighboring countries due to an ash cloud from an erupting volcano in Eritrea.