Theme 3: Tectonic Landscapes and Hazards re-do Flashcards
What are the 4 main layers of earth?
Crust
Mantle
Outer core
Inner core
What do convection currents do?
Move the tectonic plates.
What are 4 features of oceanic plates?
Less than 200 million years old
dense
will subduct
can be melted
What are 4 features of continental plates?
Over 1.5 billion years old
Less dense than oceanic plates
Will not subduct
Cannot be melted
What happens at a destructive plate boundary?
Oceanic plates subducts when plates collide.
What happens at a constructive plate boundary?
Plates move apart.
What happens at a conservative plate boundary?
Plates slide against each `other at different speeds/directions.
What are 3 features/landforms of a destructive plate boundary?
Ocean trenches
Fold mountains
Violent earthquakes and volcanoes.
What are 4 features/landforms of a constructive plate boundary?
Volcanoes formed
Less violent than destructive
New sea floor - mid-ocean ridges
Rift valleys
What are 2 features/landforms of a conservative plate boundary?
Shockwaves form earthquakes
no volcanic eruptions
What plate boundary are shield volcanoes found on?
Constructive.
What are 4 features of shield volanoes?
Gentle slopes - lava is runny
No layers
less violent than strato
More frequent eruptions than strato
What plate boundary are strato volcanoes found on?
Destructive.
What are some features of strato volcanos?
Steep sides - viscous lava
Alternating layers of ash and lava
Violent eruptions
Less frequent eruptions than shield
What is a caldera?
A large depression formed when a volcano erupts and collapses.
What are ash clouds?
Clouds of ash and dust that come out the top of volcanoes.
What are lahars?
Flows of water, rock, ash, sand and mud that originate from the slopes of a volcano.
What are lava flows?
Flows of molten rock that are extremely hot.
What are pyroclastic flows?
High speed avalanches of hot ash, rock fragments and gas that are extremely hot.
What are 3 problems ash clouds can cause?
Breathing problems
Contaminate water and crops
Disruption to climate and airlines
What is liquefaction?
When the ground starts to act like liquid (as water is forced to the surface).
What is a tsunami?
A giant wave produced by underwater earthquakes.
What is ground movement?
The shaking of the ground caused by the energy from the earthquake.
What can ground shaking affect? (4)
Damage to buildings
Disrupt habitats
Blocking roads
Burst gas lines - fire
What 4 factors can make areas more vulnerable to earthquakes/natural diasters?
Wealth
Education
Emergency services
Population density
How can wealth effect an area’s vulnerability to an earthquake?
HICs=Hazard proof buildings, warning systems.
LICs=No preventions to earthquake.
How can education effect an area’s vulnerability to an earthquake?
Being educated allows people to respond effectively to the earthquake and be aware of the dangers. Evacuation is more effective.
How can emergency services effect an area’s vulnerability to an earthquake?
HICs=Trained professionals, well resourced.
LICs=No training or resources.
How can population density effect an area’s vulnerability to an earthquake?
More people in one area= higher death rate.
In cities, high rise buildings may collapse.
What do seismographs do?
Measure plate movement to detect if earthquake is coming.
What do gas sensors do?
Detect gas that may have escaped crust when plates move.
What does remote sensing do?
Creates a thermal image of volcanoes.
What do tiltmeters do?
Detect changes in shape of volcano.
What is hazard mapping?
Highlighting areas which are dangerous in an upcoming earthquake on a map.
What does hazard mapping help with?
Knowing which areas are unsafe
Planning evacuation
Knowing to avoid building on exclusion zones
What are 4 examples of emergency planning?
Exclusion zones
Packed survival kits in homes
Evacuation routes
Public education
What are earthquake-proof buildings designed to do?
Absorb and redistribute the energy from an earthquake.
What are 4 examples of earthquake-proof designs?
Steel frames - sway during movements
Rubber shock absorbers in foundations
Open areas - easy evacuation
Safety glass- reduces injury
