page_title: Pyroclastic flow
hierarchical_section_title: Pyroclastic flow
caption_attribution_description: English: Pyroclastic flows at Mayon Volcano, Philippines, 1984. Pyroclastic flows descend the south-eastern flank of Mayon Volcano, Philippines. Maximum height of the eruption column was 15 km above sea level, and volcanic ash fell within about 50 km toward the west. There were no casualties from the 1984 eruption because more than 73,000 people evacuated the danger zones as recommended by scientists of the Philippine Institute of Volcanology and Seismology. Deutsch: Pyroklastischer Strom am Mayon auf den Philippinen (1984).
context_page_description: A pyroclastic flow is a fast-moving current of hot gas and volcanic matter that flows along the ground away from a volcano at velocities of 100 km/h on average but is capable of reaching speeds up to 700 km/h. The gases and tephra can reach temperatures of about 1,000 °C.
  Pyroclastic flows are the most deadly of all volcanic hazards and are produced as a result of certain explosive eruptions; they normally touch the ground and hurtle downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope.
context_section_description: A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) 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 velocities of 100 km/h (62 mph) on average but is capable of reaching speeds up to 700 km/h (430 mph). The gases and tephra can reach temperatures of about 1,000 °C (1,830 °F).
  Pyroclastic flows are the most deadly of all volcanic hazards  and are produced as a result of certain explosive eruptions; they normally touch the ground and hurtle downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope.
caption: Pyroclastic flows sweep down the flanks of Mayon Volcano, Philippines, in 1984
exif: {}