Definitions for "Pyroclastic surge"
Related Terms:
Nuêe ardente, Debris avalanche, Pyroclastic flow, Eruption cloud, Rockslide, Ash flow, Volcanic eruption, Debris flow, Volcano, Colluvial, Mass movement, Plinian eruption, Lahar, Volcanic bomb, Landslide, Mudflow, Caldera, Volcanism, Ejecta, Regolith, Mass wasting, Eruption, Effusive eruption, Geosyncline, Volcanic ash, Bomb , Phreatic eruption, Avalanche, Extrusive, Diatreme, Magma, Lava , Magma chamber, Fissure eruption, Volcanic cone, Cinder cone, Slide, Colluvium, Strombolian eruption, Plutonic, Earthflow, Volcanic, Deflation, Aeolian, Diapir, Landslip, Cinder cone volcano, Brash, Angular unconformity
Same process as pyroclastic flow but of much lower density.
A low-density, turbulent flow of fine-grained volcanic rock debris and hot gas. Pyroclastic surges differ from pyroclastic flows in that they are less dense and tend to travel as a low, ground-hugging, but highly mobile cloud that an surmount topographic barriers. Surges often affect areas beyond the limits of pyroclastic flows.
A turbulent cloud of gas and fine rock particles that flows over and above the ground surface at extremely high velocities. More dilute than pyroclastic flows, surges are not topographically constrained but sweep over ridges, hills, and other topographic obstacles.
a dilute suspension of pyroclasts in turbulent gas
a dilute turbulent cloud of gases and rock debris that moves above the ground surface at great speeds
similar to a pyroclastic flow but of much lower density (higher gas to rock ratio).
Pyroclastic surges are dilute, turbulent suspensions of pyroclastic particles. Surges are fast-moving mixtures of superheated volcanic ash, and gas and their behavious can be compared to a very severe hurricane. Surges can be formed either above pyoclastic flows or directly by violent explosions.
A turbulent, low-density cloud of hot rock debris and gases that moves at extremely high speeds. Because surges are low density, they tend to spread over large areas and jump ridge crests easily.
These are a flowing mixture of turbulent hot gas with suspended volcanic ash. They form by particularly intense volcanic explosions that cause the hot mixture to move at speeds of up to 400 kph. Large pyroclastic surges are relatively rare and their causes are unfortunately rather poorly understood. They are exceptionally destructive and far less constrained by topography than normal kinds of pyroclastic flow. Large magnitude surge eruptions that have occurred on other volcanoes (e.g. Mont Pelee on Martinique, 1902 and Mount Lamington in Papua New Guinea, 1951) can cover large areas and the more extreme events of this kind are known to have surmounted topographic barriers as high as the Centre Hills (Figure 1). The deposits from these events are thin and are easily eroded, making it hard to prove that such events have never happened at the Soufriere Hills volcano.
These are also flows, but they are dilute clouds rather than dense avalanches. Surges are fast-moving mixtures of hot ash and gas and their behaviour can be compared to a very severe hurricane. Surges can be formed either above pyroclastic flows or directly by very violent explosions.
These are also flows, but they are dilute clouds rather than dense avalanches. A surge is a rapidly moving mixture of hot particles and hot gas and their behaviour can be compared to a very severe hurricane. Surges can be formed above pyroclastic flows or directly by very violent explosions.
Like pyroclastic flows, pyroclastic surges are very fast moving clouds of gas and volcanic particles, and are very destructive. Some differences between the two are that pyroclastic surges travel faster than pyroclastic flows, cover less distance and deposit thinner layers of volcanic material than pyroclastic flows do.
A pyroclastic surge is a fluidized mass of turbulent gas and rock fragments which is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but contains a much higher of proportion of gas to rock, which makes it more turbulent and allows it to rise up over ridges and hills rather than always travel downhill as pyroclastic flows do.