What is a pyroclastic flow?

pyroclastic flow is a dense combination of extremely hot gases and solid mass, which is based on a volcano during an eruption or collapse. These streams are the most dangerous aspect of volcanic activity because they travel high speeds, can cover the ground miles, are extremely hot and contain toxic gases. Although they are composed of gases and solid fragments, pyroclastic flows behave closer to the liquid than to a solid or gas. When this phenomenon occurs at low density, it is called pyroclastic overvoltage. It seems that the flow is a strong fluttering cloud, but contains solid and gaseous materials. When the flow finally stops, deposition, sometimes heavily over 328 feet (100 m).

There are two general classification of pyroclastic flows. The Nuée Ardente flow occurs when part of the lava dome or volcanic ventilation opening, Collapses. The pyroclastic flow of this nature contains solid lava fragments and gases. The first recorded instance of the Nuée Ardente flow was in 1902 during the eruption of Mount Pelée.

pump flowsIt occurs when the eruption column collapses. The resulting solid material is vesiculated or covered with small holes and is therefore less dense than fragments in the Nuee Ardente flow. These lighter fragments are called Putza.

Since it is so dense, it monitors the pyroclastic flow of ground terrain, usually spills the volcano and into the valley. When it interferes with water, it drops below the water level and usually continues to move forward. These streams can spread up to 124 miles (200 km) and can travel over 62 miles per hour (100 km/hour) and cover up to 7,722 square miles (20,000 km _{) before stopping. Extremely hot, pyroclastic streams can reach temperatures of 1,967 & Degf; (1 075 & Degc;).}

There are two main sections to the pyroclastic flow. The heavier solid particles move near the ground and create a basal flow. Above the basal flow are lighter particles and gases that create a cloud of ash. Pýmné streams have another foldercalled ground surge, which consists of clouds of ash, which jumps in front of the main flow. The ashes of ground overvoltages actually shine from the heat produced.

When the pyroclastic flow is formed by diluted materials, it is called pyroclastic overvoltage. Pyroclastic overvoltages are much lighter than flows, although they still contain gases and solid particles. Because they have a low density, they spread in the air above the ground to watch the terrain.