Tectonic Landforms and Earthquake Flashcards
An earthquake is not a landform
Define volcano
A volcano is where liquid rock (magma) erupts through the ground. Above ground, the liquid rock is called lava.
Define earthquake
An earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements of the earth’s crust or volcanic action.
Where can hot spots be found
Hawaii is above a hotspot
Hawaii is an arc of volcanic islands
Label a conservative plate margin/structure of an earthquake
Seismic waves
Plate movement, fault
Epicentre (above focus)
Focus (underground)
(look in book)
Define seismic energy
Seismic energy are the shock waves created by an earthquake
Epicentre: The point on the surface directly above an earthquake
Fault: A crack in the Earth’s crust along which plates move
Magnitude: the strength or energy of an earthquake
Focus: The point underground where the rock snaps and the earthquake starts
Define epicentre
The epicentre is the point on the surface directly above an earthquake
Define fault
A fault is a crack in the Earth’s crust along which plates move
Define magnitude
Magnitude is the strength or energy of an earthquake
Define focus
The focus is the point underground where the rock snaps and the earthquake starts
State some physical processes that can lead to earthquakes and volcanoes
Constructive plate margin
Destructive plate margin
Conservative Plate Margin
Where do most earthquakes and volcanoes occur
Most earthquakes and volcanoes occur at plate boundaries
Explain why earthquakes occur at plate margins.
[4 marks]
A destructive plate boundary is when oceanic crust moves towards continental crust. As the oceanic crust is heavier, it is subducted (forced downwards). This force and pressure can trigger earthquakes.
At conservative plate boundaries, two plates try to slide slowly past one another. When the two plates stick, pressure builds up. This pressure is then released as an earthquake.
A constructive margin is where two plates move apart. As a ‘gap’ appears between the two plates, lava can easily escape either in the form of a gentle eruption (volcano) or as a lava flow. The lava creates new oceanic crust and forms a mid-ocean ridge. Earthquakes and volcanoes can be found at constructive plate boundaries.
Earthquakes can occur at collision margins. The force and pressure from the two continental plates being pushed upwards or buckled under can trigger earthquakes.
What causes Earthquakes
Earthquakes are the sudden violent shaking of the ground. This happens because the Earth’s plates are constantly moving. Sometimes, because of friction, plates try to move and become stuck. Pressure builds up because the plates are still trying to move. When the pressure is released, it sends out huge amounts of energy in the form of seismic waves causing the Earth’s surface to shake violently.
What equipment are earthquakes measured on
A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions.
What is a seismograph
Seismometers are usually combined with a timing device and a recording device to form a seismograph.
What is the scale used to measure the intensity of an earthquake
The Richter magnitude scale is a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs.
It is numbered 1-10
How can effects be categorised
Primary Effects
Secondary Effects
What is a primary effect
PRIMARY EFFECTS Are impacts that are caused directly by the shaking of the Earth
What is a secondary effect
SECONDARY EFFECTS - Are the result of the primary effect
Give examples of primary effects
Examples of primary effects:
Death
Injury
Damage to roads
Burst pipes
Collapse of buildings
Landslides
Give examples of secondary effects
Examples of secondary effects:
Homelessness due to initial destruction of buildings
Increased crime
Death
Injury
Food shortages
Spread of disease
Fires
Tsunamis
What factors may cause the effects of an earthquake to be more severe?
Location of epicentre
Depth of focus
Time of day/week
Geology
Population density
Level of development
Prediction
Building standards
How does the depth of the cause the effects of an earthquake to be more severe
The closer the focus is to the surface (where the epicentre is located), the more severe the effects of an earthquake will be. This is because, if the distance between the focus and the epicentre is greater, the seismic waves have to travel a further distance, causing an earthquake to lose it’s intensity
How can responses by categorised
Responses can be categorised as immediate responses and long-term responses
Define immediate response
IMMEDIATE RESPONSES are emergency help (often known as disaster relief) shortly after the disaster such as food and clean water supplies.
Define long-term responses
LONG-TERM RESPONSES are a longer-term approach to helping rebuild a country after a disaster, such as rebuilding the economy and infrastructure.
How can earthquakes be predicted
Earthquakes can not be predicted. Instead experts use patterns from a seismometer to predict if they are likely to have a great effect. Moreover, increased amounts of tectonic activity measured on a seismometer could lead to an earthquake
How does the depth of the cause the effects of an earthquake to be more severe
The closer the focus is to the surface (where the epicentre is located), the more severe the effects of an earthquake will be. This is because, if the distance between the focus and the epicentre is greater, the seismic waves have to travel a further distance, causing an earthquake to lose it’s intensity
Give examples of Non-Governmental Organisations (NGO’s)
(like charities)
British Red Cross
Oxfam
Give examples of immediate responses
Rescue people trapped and treat injured people
Put out fires
Reconnect broken electricity, water and gas connections
Recover dead bodies to prevent spread of disease
Provide temporary supplies of water, food, electricity and gas.
Foreign governments or charities (NGOs) may send aid workers, supplies, equipment or financial donations.
Setup temporary shelters for people whose homes have been destroyed
Tech companies may set up disaster response tools, allowing people to confirm their safety (e.g. a user pressing a button which sends a notification to others to say that you are ok, or not. There is an increased chance of someone coming to help you, if you say that you are not ok)
Give examples of Long-term responses
Rehouse people who lost their homes
Repair or rebuild damaged buildings, roads, railways
Set up initiatives to help economic recovery e.g. promoting tourism (Long term as you wouldn’t be promoting tourism a week after a natural disaster)
Improve building regulations so that buildings are less prone to damage from tectonic hazards
