Plate Tectonics Flashcards
What are the two types of tectonic plates?
Oceanic and continental.
What are the features of oceanic plates?
Basalt, thin + dark, heavy, dense.
What are the features of continental plates?
Granite, thick, light.
What are the three types of plate movement?
Diverging/Constructive.
Converging/Destructive.
Transform/Conservative.
What is subuction?
When an oceanic plate goes under a continental plate.
What is magma?
Molten rock, lava under the earth.
What is a plate margin?
A place where one plate meets another.
What are the two types of volcanoes?
Shieldvolcanoes and Stratovolcanoes
What are the features of shield volcanoes?
Rise from the deep ocean floor
Gentle upper slopes + steeper lower slopes
Cover a wide area
Circular/oval shaped
Composed of thin lava flows and a central vent
Little pyroclastic material
Runny/basic lave, cools on lower slopes = steeper
What are the features of Stratovolcanoes?
Steeper slopes + narrower bases
Short, wide, viscous lava flows
Alternating layers of lava and pyroclastic material
More explosive
Pale lava
Long dormant periodss = very dangerous
What are craters?
Circular depressions
Formed by the explosive ejection of material from a central vent
What are calderas?
Huge crater
Caused when a volcano cone collapses into a partly empty magma chamber after a powerful eruption
What are parasitic cones?
Smaller cones on the sides of bigger volcanoes
What is a volcanic plug?
When a vent of lava cone is solidified by acid lava
Give five ways people can reduce the risk of a volcanic eruption.
- Lava flow diversion
- Mudflow barriers
- Volcano monitoring
- Remote sensing
- Building design
Give five advantages of volcanoes.
- Geothermal power
- Fertile soils
- Creating landmass
- Minerals and mining
- Created earth’s oceans and atmosphere
Case study for volcanoes.
Iceland
Weak earthquakes were a warning
A fissure ruptured
Houses collapsed
New land was formed, a new volcano was formed, lava flows threatened to block the harbor
A better coastline to block from rough seas is there
Ash used for roads
What is the point within the earth where the earthquake originates called?
the focus
What is the point on earth’s surface where the earthquake originates called?
the epicenter
What are the five damage factors that affect an earthquake’s damage?
- Energy released
- Depth of focus
- Density of population
- If the buildings are earthquake-resistant
- Solidity of bedrock
What is a tsunami?
a giant ocean wave caused by an earthquake in the ocean.
How do earthquakes happen?
plates move against each other along a fault and get stuck. when they break free it releases a lot of energy and causes an earthquake.
What does the Mercalli scale asses?
the effects of an earthquake.
What does the Richter scale asses?
the energy produced by an earthquake.
