VOLCANO ERUPTION
HOW DOES A VOLCANO ERUPTS?
DIFFERENT TYPES OF VOLCANIC ERUPTION
Prepared by:Group 3
HOW DOES A VOLCANO ERUPTS?
• There are primary factors affecting the volcanoes eruptive
style:the magma’s temperature,it’s chemical composition,and the
amount dissolved gases it contains.
• Viscosity is the property of the material’s resistance to flow.
• The more vicous and thicker the material is,the greater is its
resistance to flow.
DIFFERENT TYPES
OF
VOLCANIC ERUPTION
VOLCANOES ERUPT DIFFERENTLY.THEY ARE
GENERALLY CLASSIFIED AS WET OR DRY
DEPENDING ON THE MAGMA’S WATER CONTENT.
VOLCANOES ARE DESCRIBED ACCORDING TO THE
STYLE OF ERUPTION AS FOLLOWS:
PHREATIC OR HYDROTHERMAL
ERUPTION
PHREATIC OR HYDROTHERMAL
•
is a stream-driven eruption as the hot rocks come in contact with water.
•
It is shortlived, characterized by ash columns but may be an onset of a
larger eruption.
• A phreatic eruption, also called a phreatic explosion, ultravulcanian
eruption or steam-blast eruption
• The extreme temperature of the magma (anywhere from 500 to
1,170 °C (932 to 2,138 °F)) causes near-instantaneous evaporation
to steam, resulting in an explosion of steam, water, ash, rock, and volcanic
bombs.
PHREATOMAGMATIC ERUPTION
PHREATOMAGMATIC
• Is a violent eruption due to the contact between water and
magma.
• As a result a large column of very fine ash and high-speed and
sideway emission of pyroclastics called base surges are
observed.
• They differ from exclusively magmatic eruptions and phreatic
eruptions.
• Unlike phreatic eruptions, the products of phreatomagmatic
eruptions contain juvenile (magmatic) clasts.
STROMBOLIAN ERUPTION
STROMBOLIAN
• A periodic weak to violent eruption characterized by fountain
lava.
• relatively mild blasts with a volcanic explosivity index of
about 1 to 3.
• consist of ejection of incandescent
cinder, lapili, lava
and bombs, to altitudes of tens to a few hundreds of metres.
• They are named for the Italian volcano Stromboli.
VULCANIAN ERUPTION
VULCANIAN
• characterized by tall eruption columns that reach up to 20 km high with
pyroclastic flow and ashfall tephra.
• Mercalli described vulcanian eruptions as "...Explosions like cannon fire at
irregular intervals..."
• The term vulcanian was first used by Guiseppe Mercalli, witnessing the 1888–
1890 eruptions on the island of Vulcano.
• Their explosive nature is due to increased silica content of the magma.
PLINIAN OR VESUVIAN
ERUPTIONS
PLINIAN ERUPTION OR VESUVIAN ERUPTIONS
•
excessively explosive type of eruption of gas and pyroclastics, just like our
Pinatubo Volcano in Zambales.
• Plinian/Vesuvian eruptions are marked by columns of volcanic debris and hot
gases ejected high into the stratosphere, the second layer of Earth's
atmosphere.
• The key characteristics are ejection of large amount of pumice and very
powerful continuous gas-driven eruptions.
Trivia
Photographer Thomas vdW accidentally
captured the bright streak of a falling meteor
as he shooting an erupting volcano during a
photography trip to Kamchatka,Russia.