Mass of turbulent ash and gas that occurs in some volcanic eruptions
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.
The speed of pyroclastic density currents has been measured directly via photography only in the case of Mount St. Helens, where they reached 320-470 km/h, or 90–130 m/s (200–290 mph). Estimates of other modern eruptions are around 360 km/h, or 100 m/s (225 mph).[2] Pyroclastic flows may generate surges. For example, the city of Saint-Pierre in Martinique in 1902 was overcome by one. Pyroclastic surge include 3 types, which are base surge, ash-cloud surge, and ground surge.
^"Glossary of Volcano and Related Terminology". USGS Cascades Volcano Observatory. Retrieved on 2011-04-23.
^Belousov, Alexander; Voight, Barry; Belousova, Marina (2007). "Directed blasts and blast-generated pyroclastic density currents: a comparison of the Bezymianny 1956, Mount St Helens 1980, and Soufrière Hills, Montserrat 1997 eruptions and deposits". Bulletin of Volcanology. 69 (7). Springer Verlag: 701–740. Bibcode:2007BVol...69..701B. doi:10.1007/s00445-006-0109-y. S2CID 53540720. Retrieved 8 September 2012.
A pyroclasticsurge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic...
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...
Pompeii and Herculaneum, obliterated and buried underneath massive pyroclasticsurges and ashfall deposits, are the most famous examples. Archaeological...
incorrectly that the roaring of the pyroclastic flow was caused by a debris flow instead, and was engulfed by the pyroclasticsurge when he left the training station...
topography-draping pyroclastic fall layers, and by pyroclastic density currents (PDCs) (including pyroclastic flows and pyroclasticsurges), from which pyroclasts...
pyroclasticsurges. Likely, most of the known victims in this town were killed by the surges. People caught on the former seashore by the first surge...
Pyroclastic shield – Shield volcano formed mostly of pyroclastic and highly explosive eruptions Pyroclasticsurge – Mass of turbulent ash and gas that occurs in...
believe that the final major Krakatoa eruption was a lateral blast, or pyroclasticsurge. Around noon on 27 August 1883, a rain of hot ash fell around Ketimbang...
saving many lives. Surrounding areas were severely damaged by pyroclasticsurges, pyroclastic falls, and subsequently, by the flooding lahars caused by rainwater...
spewed an ash cloud 40 km (25 mi) into the air and produced huge pyroclasticsurges and lahar floods that devastated a large area around the volcano....
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weather system Surge (glacier), a short-lived event where a glacier can move up to velocities 100 times faster than normal Pyroclasticsurge, the fluidised...
relatively short distances. Sorting by size is more pronounced than pyroclasticsurge or pyroclastic flows. Early settling of crystals and lithic fragments near...
formation of a pyroclasticsurge (or base surge), a ground hugging radial cloud that develops along with the eruption column. Base surges are caused by...
eruptive column collapsed onto Vesuvius and its flanks. The first pyroclasticsurge, formed by a mixture of ash and hot gases, flowed down the mountain...
(980–16,400 ft). A tuff cone consists typically of thick-bedded pyroclastic flow and surge deposits created by eruption-fed density currents and bomb-scoria...
volcano shortly after the 1965 eruption and recognised "base surge" (now called pyroclasticsurge) as a process in volcanic eruption. Precursory signs were...
shallow rim, composed of erupted material that was deposited as thin pyroclasticsurge deposits. The crater is at an elevation of 4,239 ft (1,292 m). It...
°C (1,830 °F). Pyroclasticsurge Flowing mixture of gas and rock fragments ejected during some volcanic eruptions. Pyroclasticsurge refers to a specific...
heights of over 19 kilometres (62,000 ft) and which generated large pyroclasticsurges extending up to four kilometres (2.5 mi) from the summit in some river...
eruptions occurred. On 25 June 1997, a pyroclastic flow travelled down Mosquito Ghaut. This pyroclasticsurge could not be restrained by the ghaut and...
itself apart. A large surge of debris approached the aircraft, forcing its return to Lae. Changing winds directed the pyroclasticsurge northeast, where it...
eruption. The magmatic material was olivine basalt from a mantle source. Pyroclasticsurge from the eruptions traveled to the northwest. The volume of lava erupted...
believed to have been formed about 30,000 years ago with a succession of pyroclasticsurges. It is currently the place of residence to over 900,000 people. The...
civilisation in a pyroclasticsurge, a cloud of ash and superheated gases (100-499 degrees c) traveling at 100-200 kilometers an hour. This surge instantaneously...
has revealed alternations of pumice and ash deposits covered by the pyroclasticsurge and flow sediments that vary in thickness regionally. The eruption...
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