Lesson 1: Volcanoes Flashcards
The word volcano is derived from the word “_____,” a volcanic island in the Aeolian Islands of Italy
Vulcano
Vulcano is originated from the name “_______” the God of fire in Roman mythology
Vulcan
This type of volcano can produce violent, life threatening eruptions
Andesitic Types
a bowl-shaped depression
crater
connected to the magma chamber by the ______
vent
these are usually less than 1km in diameter
crater
these are much larger than the crater, they can reach up to 50 km in diameter
Calderas
these are formed when the summit of the side of the volcano collapses onto the magma chamber
Calderas
when calderas are formed, the collapsed walls of volcanoes form _____ that can stand several meters above the surface of water
cliffs
a vent or “chimney” that connects molten rock (magma) from within the earth’s crust to the earth’s surface
volcano
how are volcanoes formed?
When plates collide and one of them goes under the other, Plate collisions cause rocks to melt due to mantle heat, forming magma. High pressure and high temperature cause magma to break into the surface.
magma release into the surface is now called ____
lava
it is the most striking part of the volcano, usually composed of lava and pyroclastic
cone
viscous and slow-moving grantic magma forms ________
high-sided steep cones
fast-moving basaltic magma creates ________
low to almost flat cones
the opening through which an eruption takes place
vent
this main part of a volcano supplies the magma from the underlying source to the top of the volcano.
vent
they can be straight or curvatured
vent
the large underground pool of liquid rock found beneath the earth’s crust
magma chamber
a basin-like depression over a vent at the summit of the cone
crater
the rock or magma expelled from a volcano
lava
lava temperature upon ejection can reach up to ______°C hence it flows until it cools and hardens
700°C
the barrier or obstacles in a volcano
dikes
otherwise known as intrusive sheets; they solidify lava flows that originally forced their way between and parallel to older later of rocks
sills
a channel or pipe conveying liquid materials such as magma
conduit
the side of a volcani
flank
the highest point or apex of a volcano
summit
the entrance of a volcano
throat
expelled in the atmosphere; composed of pulverized rock and glass created during eruption
ash cloud
the chuck of lava blasted into the air which solidify before reaching the ground
volcanic bombs
fast-moving currents of hot gases and rock travelling downhill from a volcano
pyroclastic flow
refers to fragmented material that consists of pumice, scoria, lithic materials, or crystal or combination of the four
tephra fall
also called mudflows; they are flowing mixtures of volcanic debris and water
lahar
they are classified as primary hot when associated with volcanic eruption, or as cold ____ when they are caused by heavy rainfall
lahar
what are the diff. pyroclastic materials
• volcanic ashes
• lapillus
• volcanic blocks
• volcanic bombs
• lahar
very fine, grained fragment of pulverized rock, minerals and volcanic glass
volcanic ashes
made up of molten or semi molten lava, which falls on earth while still partially molten
lapillus
ejected from explosive volcanic eruptions and may consist of broken pieces of the volcano’s edifice
volcanic blocks
how and why do volcanoes erupt?
Hot, molten rock (magma) is buoyant (has a lower density than the surrounding rocks) and will rise up through the crust to erupt on the surface.
Same principle as hot air rising, e.g. how a hot air balloon works
what are the three products from an explosive eruption
• ash fall
• pyroclastic flow
• pyroclastic surge
Erupt 10’s-1000’s km³ of magma
Send ash clouds >25 km into the stratosphere
Have severe environmental and climatic effects Hazardous!!!
explosive eruptions
what are the three types of volcanoes according to their activity
active
inactive
extinct
those that have erupted over the last 10,000 years and still continue to erupt
active volcanoes
those that do not erupt as of today but have a potential to do so
inactive volcanoes
those that have not shown signs of activity for a long period of time. it has no record of volcanic eruptions in the past thousand years
extinct volcanoes
what are the diff. typed of volcanic eruption
• explosive or violent eruptions
• quiet or non- explosive eruption
lava ejected is torn into shreds, forming pieces of pyroclastic materials called tephra.
explosive or violent eruptions
can eject a large amount of materials into the air.
explosive or violent eruptions
basaltic magma has relatively low silica content. It is less viscous and gases can escape readily from it
quiet or non- explosive eruption
has wide base with gentle sloping sides. the cone is made up purely of lava that has poured out and solidified during a mild or quiet eruption.
shield volcano
is built almost entirely of loose fragments called cinders (pyroclast and tephra. formed by explosive eruptions eject lava and rocks into the air.
cinder cone volcano
composed of alternating layers of the lava and cinders (pyroclast). they are formed when volcanic eruptions vary between quiet and violent or explosive.
composite volcano / stratovolcano
