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Wednesday, January 15, 2020

What is a Phreatic Eruption? Volcano Fast Facts [Volcanic Types of Eruption] [VIDEO]

WATCH: What is a Phreatic Eruption Video? Volcano Fast Facts [Volcanic Eruption] - explained in 3D Animation
This video shed some light on the complicated, language of science. Think of this as your terminology tour-guides.
Sources: 

1. Phreatic comes from the Ancient Greek phrear, which meant “well,” or “spring.” It’s also related to the word “brew.”
2. A phreatic eruption is made up of steam-driven explosions that occur when water beneath the ground or on the surface is heated by volcanic activity.
3. The water, once heated, begins to boil or can even flash straight to steam, causing an explosion.
4. Phreatic or “steam-blast” eruption occurs when steam is produced from the contact of cold groundwater with hot rock or magma. 
5. During phreatic eruptions, no new magma is produced. Only fragments of preexisting solid rock in the volcano are expelled.
6. Also known as ultravulcanian eruption, the USGS says a phreatic eruption is “generally weak.”
7. Groundwater can often be found near volcanic vents, and as the magma rises to the surface of the earth, it heats the groundwater and cause Phreatic eruption.
8. Phreatic eruptions typically include steam and rock fragments; the inclusion of liquid lava is unusual.
9. If molten magma is included, volcanologists classify the event as a phreatomagmatic eruption.
10. Phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas-emissions.
11. These eruptions occasionally create broad, low-relief craters called maars.
12. Phreatic eruptions can often precede, accompany, or follow a more traditional volcanic eruption. 


A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption,[1] occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from 500 to 1,170 °C (932 to 2,138 °F)) causes near-instantaneous evaporation of water to steam, resulting in an explosion of steam, water, ash, rock, and volcanic bombs.

Phreatic eruptions typically include steam and rock fragments; the inclusion of liquid lava is unusual. The temperature of the fragments can range from cold to incandescent. If molten magma is included, volcanologists classify the event as a phreatomagmatic eruption. These eruptions occasionally create broad, low-relief craters called maars. Phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas-emissions. Carbon dioxide can asphyxiate at sufficient concentration; hydrogen sulfide acts as a broad-spectrum poison. 

Volcanologists class phreatic eruptions as volcanic eruptions because a phreatic eruption can bring juvenile material to the surface.

Examples of Phreatic eruptions
Krakatoa - Indonesia, 1883 (see 1883 eruption of Krakatoa) - 
Kilauea - Hawaii, United States - the volcano has a long record of phreatic explosions; a 1924 phreatic eruption hurled rocks estimated at eight tons up to a distance of one kilometer.[6]
Surtsey - Iceland, 1963-65
Taal Volcano - Philippines, 1977, 2020
Mount Tarumae - Japan, 1982
Mount Ontake - Japan, 2014 (see 2014 Mount Ontake eruption)
Mayon Volcano - Philippines, 2013
Whakaari/White Island - New Zealand, 2019 (see 2019 Whakaari/White Island eruption)

What is a phreatic eruption?
A kilometers-high column of ash emitted from Taal Volcano on Sunday morning, in what the Philippine Institute of Volcanology and Seismology (PHIVOLCS) described as a phreatic eruption from hydrothermal activities.
Later that evening, the agency issued Alert Level 4, meaning that a hazardous eruption is imminent in hours or days.
But what is a phreatic eruption?
According to the United States Geological Survey (USGS) a phreatic eruption is a "steam-driven explosion" that happens magma heats the ground or surface water.
The intense heat can cause water to boil and flash into steam, which results in an explosion of water, steam, rock and ash.

Phreatic eruptions can also often precede, accompany or follow a more traditional volcanic eruption. In the early hours of Monday, Taal Volcano spewed lava fountains, in what PHILVOLCS said can be considered a "low-level" eruption.  In its 8 a.m. bulletin, PHIVOLCS said that Taal Volcano's initial phreatic activity had progressed into a magmatic eruption from 2:49 a.m. to 4:28 a.m.

"This magmatic eruption is characterized by weak lava fountaining accompanied by thunder and flashes of lightning," PHIVOLCS said.

USGS added it can also "deform the ground surface and cause anomalous heat flow or changes in the temperature and chemistry of the groundwater and spring waters." Taal Volcano's last major eruption happened almost 43 years ago on October 3, 1977. In 2018, Mayon Volcano in Albay also experienced a phreatic eruption, but there were no threats of major volcanic activity.


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Yodi Insigne
Yodi Insigne is one of those delusional sorts who imagines himself a useful contributor to the greater blogosphere (Well, that's what he's trying to accomplish).

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