Deck 1 - Tectonics distribution and plate boundaries Flashcards
What are two categories of tectonic hazard?
1) Seismic
2) Volcanic
Where do the majority of earthquakes occur?
The majority of earthquakes are found along plate boundaries. About 70% of all earthquakes are found in the ‘Ring of Fire’ in the Pacific Ocean
What is a intra-plate earthquake?
Intra-plate earthquakes occur in the middle of a tectonic plate
What secondary hazards are associated with earthquakes?
Landslides, avalanches, tsunamis
Where are the majority of volcanoes found?
There are about 500 active volcanoes around the world with on average 50 erupting each year. The majority are found on plate boundaries with a large concentration around the Pacific Ocean (Ring of Fire
What is a hot spot volcano?
An intra-plate volcano that is located above a mantle plume
What is a constructive (divergent) plate margin?
A plate boundary where tectonic plates are moving away from each other allowing for magma to move to the surface to create new land
What is a destructive (convergent) plate margin?
A plate margin where tectonic plates are moving towards each other. Oceanic plate is denser than continental plate meaning it is subducted
What is a conservative plate margin?
A plate margin where tectonic plates move alongside each other. Plates are either moving in opposite direction or the same direction at different speeds
What is a collision boundary?
A destructive margin where both plates are of equal density meaning that neither plate subducts resulting in an upwards buckling creating fold mountains such as the Himalayas.
Which type of plate boundaries do you find earthquakes at?
All
Which type of plate boundaries do you find volcanoes at?
Constructive and destructive
Where is the lithosphere found and what is it made of?
The lithosphere is the outermost layer of the Earth when viewed from the physical properties model. It is about 100km thick and is thicker beneath continents. Continental lithosphere is made of ‘granitic’ rocks whereas oceanic lithosphere is made of ‘basaltic’ rocks.
Where is the asthenosphere found and what is it made of?
The asthenosphere is 250km thick and is found to a depth of 350km. It is below the lithosphere and is made of solid rock that is ductile so flows easily.
Where is the mesosphere found and what is it made of?
The mesosphere is around 2500km thick and is found between the asthenosphere and outer core. It is made of solid rock and is less ductile than the asthenosphere but is still capable of flowing.