Search results
Results From The WOW.Com Content Network
Volcanic gases are gases given off by active (or, at times, by dormant) volcanoes. These include gases trapped in cavities ( vesicles ) in volcanic rocks , dissolved or dissociated gases in magma and lava , or gases emanating from lava, from volcanic craters or vents.
Pyroclastic flows sweep down the flanks of Mayon Volcano, Philippines, in 2018. A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) [1] is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of 100 km/h (30 m/s; 60 mph) but is capable of reaching speeds up to ...
The shapes were formed around bubbles of expanding, water-rich gas. Tephra is made when magma inside the volcano is blown apart by the rapid expansion of hot volcanic gases. Magma commonly explodes as the gas dissolved in it comes out of solution as the pressure decreases when it flows to the surface. These violent explosions produce particles ...
A pyroclastic surge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions.It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, [1] which makes it more turbulent and allows it to rise over ridges and hills rather than always travel downhill as pyroclastic flows do.
A volcanic eruption is essentially the only natural way for short-lived – less than a few years – gases like sulfur dioxide and water vapor to make it into the stratosphere.
For example, volcanic ejecta, pyroclastic flow from a collapsing lava dome, lahars, poisonous gases that travel ahead of lava, or explosions caused when the flow comes into contact with water. [83] A particularly dangerous area is called a lava bench. This very young ground will typically break off and fall into the sea.
Fumaroles, or volcanic vents, are holes in the ground from which volcanic vapors and gases escape to the atmosphere. Geothermally active areas are often located over an active magma chamber, which constantly releases hot gases that travel to the surface through cavities in the rock. Where these cavities reach the surface they form fumaroles.
Mazuku forming in a low morphological depression on the foothills of Mt. Amiata, Italy, where CO 2-rich fog accumulates in a ditch. Mazuku (Swahili for "evil winds") are pockets of dry, cold carbon dioxide-rich gases released from vents or fissures in volcanically and tectonically active areas, and mixed with dispersed atmospheric air and accumulating in typically low-lying areas.