Tectonic Content Flashcards
(32 cards)
What are the 3 plate boundary types
Divergent, convergent and conservative
What are and what happens at convergent plate boundaries
Convergent plate boundaries are where the two plates move towards each other ->
What happens at divergent plate boundaries
Divergent plate boundaries is where the two plates are pulling apart from each other. This can create shield volcanos (volcanos with thin and runny lava)
What happens at conservative plate boundaries
This is where two plates slide past each other either in opposite directions or the same direction at different speeds. This can create earthquakes
How do Intra plate earthquakes occur?
These earthquakes are caused by stresses within a plate. This is due to the fact plates move over a spherical surface, so weakness zones are created and this is where the quakes occur.
Why do hotspot volcanos appear
These are intraplate volcanos which form due to a mantle plume melting through the crust and then the magma starts to overflow
How do earthquakes occur
This is where the friction along the plate boundaries is so high it causes a locked fault and once all this built up pressure and energy is released it creates an earthquake
What is the hypocentre of an earthquake
This is also known as the focus of the earthquake and is the exact centre of the earthquake and where all of the waves are released from
What is the epicentre of an earthquake
This is the centre of an earthquake on the surface
What are the waves that make up an earthquake
The seismic waves that make an earthquake consist of: primary waves are the first and fastest waves released and can move through both rock and fluids. It pushes and pulls the rock and moves just like sound waves.
Secondary waves are the waves which are the waves that are felt. These are slower than primary waves and can only travel through solid rock. These move rock particles move up and down or side to side.
Finally there are love waves which are a surface waves. These move the ground from side to side.
What are the primary hazards of earthquakes
Primary hazards include ground shaking, landslides, liquefaction sand in some areas tsunamis.
What are the secondary hazards of earthquakes
These primary hazards can then cause the secondary hazards: ruptured utility lines, hazardous spills and fires
How are earthquakes measured
They are measured using moment magnitude and mercallis scale. Moment magnitude measures the size of an earthquake and mercalli measures the intensity
When and where die the Christchurch quake happen
It happened on the 22nd February 2011 and happened in the Canterbury region in New Zealand and the epicentre was 6 miles south east of Christchurch
What are some key facts about the Christchurch earthquake
Liquefaction around the areas produced 400,000 tonnes of silt. It occurred along a conservative plate margin. It was an 8 on the mercalli scale.
What are some key impacts of the Christchurch earthquake
185 deaths, 130km of sewage pipes were destroyed, £40 billion lost, 50% of the centres buildings destroyed.
When and where did the Haiti earthquake occur
This occurred on the 12th of January 2010 on the West Indian island of Hispaniola.
What are some key factors of the Haiti quake
It was originally a magnitude 7 but then had two aftershocks at 5.9 and 5.5. The largest quake since 18th century. Had a shallow focus of 13km.
What are the key impacts of the Haiti quake
It created £8 billion damages. 1/4 civil servants were killed. 80% of schools were closed. 3.5 million people affected. Over 200,000 killed. 300,000 homes destroyed leaving 1.5 mill homeless
What is tephra
Tephra is rock fragments and particle ejected from the volcanos
What are lahars
destructive mudflow on the slopes of a volcano.
What are basaltic volcanos?
These are on shield volcanos when andesitic volcanose are strata volcanos.
When did the Eyjafjallajökull eruption occur
It happened at the end of 2009 until the 20th March 2010
What happened at the Eyjafjallajökull quake
The first phase produced a spew of 1660 metres. Over 800 people were evacuated.
