Weather hazard - part 2 Flashcards
What are the layers of the earth?
inner core, outer core, mantle and crust
What are the two types of crust?
oceanic and continental
Is oceanic crust more or less dense?
it is more dense than continental
can continental crust be renewed or destroyed ?
it cannot
What is convection currents?
Heated rock from the mantle rises and spreads out carrying the plates.
What does subduction mean ?
pushed down
What are the 4 types of plate boundaries?
destructive
conservative
constructive
collision
What happens at a destructive plate boundary ?
Oceanic plate is subducted under the continental plate.
does earthquakes and volcanos (fold mountains) happen at a destructive plate boundary
yes, both
What is an example of fold mountains at a destructive plate boundary ?
The Andes fold mountains in south America.
What direction are the plates moving in at a collision plate boundary?
They move towards each other
do earthquakes happen at a collision plate boundary?
yes and not volcanos because no subduction causes magma to rise
What is an example of what happens at a collision plate boundary?
The Himalayas mountains
What way are the plates moving at a constructive plate boundary ?
Away from each other
Do earthquakes happen at a constructive plate boundary?
yes, usually small
Do volcanos form at a constructive plate boundary?
yes
Under what type of crust are constructive plate boundaries usually found?
Oceanic. the magma rising create volcanic islands in the ridge and form new crust in the ocean.
What is an example of a constructive plate boundary?
Iceland, which was formed by the north American plate and the Eurasian plate moving away from each other.
What happens at a conservative plate boundary?
They slide past each other, friction builds up causing them to get stuck and pressure is built up. when the pressure is released the sudden movements cause earthquakes.
San Andreas faults is an example of what plate boundary?
conservative plate boundary
What are the two types of volcanos?
composite and shield volcanos
Describe a composite volcano
They have steep slopes and a narrow base, this is because the lava is thick and viscous and travels short distances.
What is a hot spot volcano?
Its a mantle plume which lift the crust and cracks it. when it rises it forms a volcano, the plates move sideways which forms a line of volcanos. the oldest are the most eroded.
What is a magma chamber?
A large pool of underground liquid rock found beneath the surface of the earth.
What is a crater?
Circular depression around a volcanic vent created after an eruption.
List 3 impacts of earthquakes:
Could have:
- death/injury
- damaged or destroyed infrastructure
- ruined crops - economic rebuild cost
- destroyed homes
- trapped people
- transport links cut off
- water spills due to split pipes
The point at which an earthquake starts underground is known as the ‘…..’
focus
What is directly above the focus?
epicentre
‘……. …..’ are transmitted from the focus and release the earthquakes energy.
seismic waves
What is a seismometer?
An instrument used to detect any sudden movements in the earths crust.
Whare are the 2 different scales used when measuring earthquakes?
The richter scale and the mercalli scale
What does the Mercalli scare measure up to and in what format?
Xii and in roman numerals
What doe the richter scale measure and up to what?
Measures magnitude of an earthquake on a scale 1-10.
What does a logarithmic scale mean?
each number is x10 more than the last number below.
What’s the difference between a deep focus earthquake and a shallow focus earthquake?
A deep focus earthquake happen 70-700km below the ground and spread out vertically therefore effect a smaller area where as a shallow focus earthquake happen 0-70km below the surface and spread out horizontally effecting a larger area of damage.
What 2 countries does Nepal border?
china and india
Nepal isn’t well developed meaning is classed as a what kid of country?
Low-income developing country (LIDC)
What was the magnitude of the Nepal earthquake the happened in 2015?
7.8 and a shallow focus earthquake (15km under the surface)
What was the cause of the 2015 earthquake that happened in Nepal?
It was caused by the Indian plate and the Eurasian plate colliding at a collision plate boundary.
How many people were injured in the 2015 earthquake?
19,009 people
How many people were killed in the 2015 earthquake?
8,635 people
What were the economic consequences to the 2015 earthquake in Nepal?
-180 building reduced to rubble in Kathmandu
- $10 billion of damage caused
- aftershocks threatened weakened buildings
- historical and religious buildings were destroyed
What are social consequences to the 2015 earthquake?
- homes and buildings lost
- people were killed or injured
- thousands of people were made homeless
What are environmental consequences to the 2015 earthquake ?
- Aftershocks
- landslides in the mountains
What does the landscape of Nepal affect?
The mountainous landscape adds more danger due to the increased risk of landslide which cuts of connections between villages and towns and can also destroy villages located in valleys.
