Summary: Volcanoes
It's the end of our chapter, VOLCANO. Let us summarize what we had discussed in the past 19 blog posts. What are we waiting for. Let's finish this chapter for us to proceed to the next. What are you we waiting for?
PARTS OF THE VOLCANO
CRATER
Mouth of a volcano that surrounds the vent.
VENT
The opening in the volcano from where the lava comes out.
LAVA
Molten rock which erupts from a volcano.
MAGMA
Molten rock under the surface of the Earth.
SUMMIT
Highest point of the volcano
ASH
Small parts of lava or rocks which are shot in the air by explosion.
ASH CLOUDS
A cloud of ash formed by volcanic eruptions.
Pyroclastic Materials – another name for a cloud of ash, lava fragments carried through the air, and vapor.
Pyroclastic Flow – contain a high-density mix of hot lava blocks, pumice, ash and volcanic gas.
SILL
A flat piece of rock which forms by the hardening of magma in a crack in a volcano.
CONDUIT
The passage in the volcano through which magma travels up.
THROAT
Conduit’s part that ejects lava and volcanic ash.
PARASITIC CONE
A cone-shaped accumulation of volcanic material not part of the central vent of a volcano.
PLATE BOUNDARIES
CONVERGENT BOUNDARIES: where two plates are colliding.
DIVERGENT BOUNDARIES– where two plates are moving apart. ...
TRANSFORM BOUNDARIES – where plates slide passed each other.
CLASSIFICATION OF VOLCANO
EXTINCT VOLCANO - An extinct volcano has not had an eruption for at least 10,000 years and is not expected to erupt again in a comparable time scale of the future.
DORMANT VOLCANO - A dormant volcano is an active volcano that is not erupting, but supposed to erupt again.
ACTIVE VOLCANO - An active volcano is a volcano that has had at least one eruption during the past 10,000 years
TYPES OF MAGMA
Basaltic Magma - Mafic lava is molten rock that is enriched in iron and magnesium and low in silica. When mafic magma cools on the earth's surface, it forms basalt.
Andesitic Magma - Andesitic magma a dark-colored volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals, as hornblende or biotite.
Rhyolitic Magma - A type of magma formed by differentiation from basaltic magma in combination with assimilation of siliceous material, orby melting of portions of the earth's sialic layer.
TYPES OF LAVA
A'a Lava - A lava that flows rapidly.
Pahoehoe - A lava that flows slower than A'a lava.
Pillow Lava - Pillow-liked structured lava usually found underwater.
TYPES OF VOLCANIC CONE
Cinder Cone - A cinder cone or scoria cone is a steep conical hill of loose pyroclastic fragments
Composite - A composite volcano is also known as a stratovolcano. These volcanoes form tall, conical shaped mountains.
Shield - A shield volcano is a type of volcano usually built almost entirely of fluid lava
flows.
Lava Dome - lava dome or volcanic dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano
Caldera - They are large volcanic craters that form by two different methods: 1) an explosive volcanic eruption; or, 2) collapse of surface rock into an empty magma chamber.
Lava Plateau - Lava plateaus are extensive areas of flood basalt which are formed by the extensive eruption of basaltic lava over a large area.
TYPES OF VOLCANIC ERUPTION
Phreatic or Hydrothermal Eruption - This is a stream-driven eruption as the hot rock come in contact with water.
Phreatomagmatic Eruption - This is a violent eruption due to the contact between water and magma.
Strombolian Eruption - This is a periodic weak to violent eruption characterized by fountain lava.
Vulcanian Eruption - This is characterized by tall eruption columns that reach up to 20 km high with pyroclastic flow and ashfall tephra.
Plinian Eruption - This is excessively explosive type of eruption of gas and pyroclastics.
