Volcanic Eruptions

Kinds of Volcanic Eruptions

1. Effusive Eruptions - An eruption dominated by the outpouring of lava onto the ground is often referred to as an effusive eruption

2. Explosive Eruptions - An energetic eruption that produces mainly ash, pumice, and fragmental ballistic debris

Types of Volcanic Eruptions

1. Hawaiian - a type of volcanic eruption where lava flows from the vent in a relatively gentle, low level eruption; it is so named because it is characteristic of Hawaiian volcanoes

2. Icelandic - characterized by effusions of molten basaltic lava that flow from long, parallel fissures. Such outpourings often build lava plateaus.

3. Strombolian - These eruptions are characterized by distinct blasts of basaltic to andesitic magma from the vent. These blasts produce incandescent bombs that fall near the vent, eventually building a small cone of tephra (cinder cone).

- Sometimes lava flows erupt from vents low on the flanks of the small cones. Strombolian eruptions are considered mildly explosive, and produce low elevation eruption columns and pyroclastic fall deposits

4. Vulcanian - This type of eruption results from the fragmentation and explosion of a plug of lava in avolcanic conduit, or from the rupture of a lava dome (viscous lava that piles up over a vent)

- a short, violent, relatively small explosion of viscous magma (usually andesite, dacite, or rhyolite)

5. Pelean - associated with explosive outbursts that generate pyroclastic flows, dense mixtures of hot volcanic fragments and gas

- Pelean eruptions are named for the destructive eruption of Mount Pelée on the Caribbean island of Martinique in 1902.

6. Phreatic - steam-driven explosions that occur when water beneath the ground or on the surface is heated by magma, lava, hot rocks, or new volcanic deposits (for example, tephra and pyroclastic-flow deposits)

- The intense heat of such material (as high as 1,170 ° C for basaltic lava) may cause water to boil and flash to steam, thereby generating an explosion of steam, water, ash, blocks, and bombs.

(The Reporters thought Mt Mayon released ashes when it fact it was just a phreatic eruption)

7. Phreatomagmatic - An eruption that involves both magma and water, which typically interact explosively, leading to concurrent ejection of steam and pyroclastic fragments

8. Plinian - large explosive events that form enormous dark columns of tephra and gas high into the stratosphere (>11 km)

- Such eruptions are named for Pliny the Younger, who carefully described the disastrous eruption of Vesuvius in 79 A.D

- This eruption generated a huge column of tephra into the sky, pyroclastic flows and surges, and extensive ash fall. Many thousands of people evacuated areas around the volcano, but about 2,000 were killed, including Pliny the Older.

References:

1. https://volcanoes.usgs.gov/vsc/glossary/explosive_eruption.html

2. https://en.wikipedia.org/wiki/Hawaiian_eruption

3. https://youtu.be/Biakg73c7DM

4. https://www.youtube.com/watch?v=90XFpu-65JY

5. http://geology.com/volcanoes/types-of-volcanic-eruptions/

6. https://www.youtube.com/watch?v=mIX43uy4Zvg