When this ash is ejected in large amounts tend to be cemented to form a rock known as tuff.
Summary
Specifications
Volcanic ash observed SEMUnlike the ash resulting from combustion, volcanic ash is hard and abrasive. They do not dissolve in water and conduct electricity well especially when wet. During a rain of ashes the sky seems cloudy or yellowish and smells of sulfur in the air.
Hazards
Private clearing the ashes on the wings of a B-25 bomber U.S. in 1944 after a rash of Vesuvius.Breathing volcanic ash can pose problems for people suffering from respiratory problems. Their abrasive surfaces may cause irritation of the skin and mucous membranes. The combination of ash and moisture in the lungs can turn into a cement slurry which can obstruct breathing. Therefore it is advised to breathe through a cloth or a mask.
Ash Rain
Aerial view of part of the facilities airbase U.S. Clark covered with volcanic ash. Under their weight, the roofs of the warehouses collapsed (Pinatubo, 1991).Category: Ash Rain.
During the eruption of Vesuvius 1906, the collapse of the roof of the church San Giuseppe VesuvianoCaused by the rain of ashes, killed the 105 people who had taken refuge there to pray.
Combined effects of other factors
The Lahar are torrents of mud that invaded the plains and valleys. These are a mixture of volcanic ash and water, the water from rain or melting snow or ice.
The greatest danger comes from pyroclastic which are a mixture of gases, ash and rocks hurtling down such a deadly avalanche slopes of the volcano. In 1902The City Saint-Pierre in Martinique was destroyed by a pyroclastic flow that killed over 29,000 people.
Ash and Aviation Safety
Volcanic ash clouds pose a real danger to Aviation Safety. Thus, according Weather France, Volcanic ash, rock particles which can reach the highest heights of tens of kilometers and with smaller particles are 1 to 15 um, can spend several days in air. They can be transported by winds of troposphereThe stratosphereOver very long distances. One hundred incidents on flights longhaulSince 1980, are related to volcanic activity.
The turbine aircraft ingests volcanic ash present in contaminated air. The nominal operating temperature of motors is 1400C. However, ash, consisting of silicates, Based upon a temperature of 1100 ° C is reached. The bottom ash, therefore the nozzle guide vanes and turbine blades in the hot engine. The engine can then burn. The older aircraft were equipped with engines operating at a lower temperature. They could not therefore be the weak point.
The most serious incident reported, involved the 747 of British Airways Flight 9 including the four engines were arrested. However, after a fall a few miles, and the area of ash away, the pilot was able to restart both engines. Following theEyjafjöll eruption in 2010 and dated April 17, 2010, no accidents were caused by volcanic ash.
Outside of a catastrophic accident may be caused by the loss of engines, other risks are taken into account. The hardness and abrasiveness of the material, leading to erosion of the surfaces of aircraft flying, and parts of jet engines. The window of the cockpit can reduce or eliminate the forward visibility of drivers. The more, the fineness of the material allows it to pass through the filtration systems, and thus contaminate the cooling systems, electrical and avionics units. This reduces all the ease of piloting the aircraft. Volcanic ash can be accompanied bysulfuric acidH2SO4.
Atmospheric effects
These particles can remain for years in the upper atmosphere, if large quantities are released they may even influence the global climate (see the eruption of Pinatubo 1991).
Source:wikipedia
No comments:
Post a Comment