Pyroclastic rocks (derived from the Greek: πῦρ, meaning fire; and κλαστός, meaning broken) are clastic rocks composed of rock fragments produced by explosive volcanism and erupted as individual particles. Pyroclastic flow A pyroclastic flow is a ground-hugging avalanche of hot ash, pumice, rock fragments, and volcanic gas that rushes down the side of a volcano as fast as 100 km/hour or more. Pyroclastic flows are a very dangerous phenomenon that occur during some volcanic eruptions. Pyroclastic flows are a type of pyroclastic density current consisting of heterogeneous mixtures of hot volcanic particles and gas flowing due to gravity with a higher density than that of air. Pyroclastic flows and surges Montserrat, West Indies, 1996 The difference between a pyroclastic flow and a pyroclastic surge is one of degree:- Flows are more dense than surges, consequently they tend to follow topography along predictable paths. One of the most spectacular forms of pyroclastic deposit are the ignimbrites, deposits formed by the high-temperature gas-and-ash mix of a pyroclastic flow event. The flows were entirely restricted to a small fan-shaped zone that flares northward from the summit crater. Pyroclastic flows originated in both ways at Mount St. Helens on May 18, but flows of mappable volume were of the latter type. The following kinds of pyroclastic surge deposits (the general name for all types of low-concentration pyroclastic flows, named on the basis of origin and/or place in sequence), have been indentified: https://www.nationalgeographic.org/encyclopedia/pyroclastic-flow Ash is considered to be pyroclastic because it is a fine dust made up of volcanic rock. Pyroclastic flows are a mixture of hot gas along with volcanic matter, like ash and rock fragments, she said. pyroclastic flow deposits has significant implications with respect to eruption and flow mechanics. Surges are less dense, they move more quickly and can surmount topography such as hills and ridges. The materials in the flow can be heated from as low as 100 degrees all the way up 800 degrees Fahrenheit. Pyroclastic Flow or Nuee Ardente (French: Fiery Cloud) GL-2241. We also describe the eruption style and the deposits of different kinds of pyroclastic falls, flows and surges, based on studies of Quaternary volcanoes. Basically, pyroclastic flows are fluidized masses of gases, rocks, and ash that can exit out of a volcano and travel away from the volcano across the land. A pyroclastic flow is the flow of volcanic ash, gases and fragments following a volcanic eruption. Pyroclasts of different sizes are classified as volcanic bombs, lapilli, and volcanic ash. Pyroclastic flows. They are incredibly hot and can travel faster than a moving vehicle in some cases. The individual rock fragments are known as pyroclasts.Pyroclastic rocks are a type of volcaniclastic deposit. 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