What are the characteristics of the inner core of the Earth?
Enjoying Flashcards?
Tell us what you think
What are the characteristics of the inner core of the Earth?
The characteristics of the inner core are:
It is a solid and dense layer.
About 1400 km in diameter.
Composed of iron and nickel.
Has a temperature of about 5500 °C.
True or False?
The oceanic crust is older than the continental crust.
False.
The continental crust is older than the oceanic crust, as the oceanic crust is continually being created and destroyed.
Where do most of the world's earthquakes occur?
Most earthquakes (approx. 90%) occur along the Pacific 'Ring of Fire'.
Define the term hotspot.
A hotspot is a plume or column of magma that escapes through the Earth's crust away from plate boundaries, forming volcanoes.
True or False?
Volcanic eruptions mainly happen at conservative and destructive boundaries.
False.
Volcanoes mainly occur at constructive and destructive plate boundaries.
Define the term pyroclastic flow.
A pyroclastic flow is a dense, destructive mass of very hot ash, rock fragments and gases that flows rapidly down slopes during a volcanic eruption.
True or False?
Volcanic bombs are a secondary hazard of volcanic eruptions.
False.
Volcanic bombs are a primary hazard emitted directly from the volcano.
State the meaning of the slab pull theory.
Slab pull theory suggests plate movement is caused by the weight of denser oceanic plates subducting and dragging the rest of the plate.
Define the term plate boundary.
A plate boundary or margin is where two plates meet
The Mid Atlantic Ridge is an example of what type of plate boundary?
The Mid Atlantic Ridge is an example of a constructive plate boundary
What is the difference between a primary and secondary effect of a tectonic hazard?
Primary effects occur directly from the hazard itself, while secondary effects result from the primary effects.
Give an example of a primary effect of an earthquake.
Examples of a primary earthquake effect are:
Buildings and homes are destroyed or damaged.
People are injured or killed.
Transport routes are destroyed or damaged.
Water, gas and electricity supplies are cut.
True or False?
A lack of clean water leading to disease is a primary effect of a volcanic eruption.
False.
A lack of clean water is a secondary effect, caused by the primary volcanic hazards contaminating water supplies.
Give one long-term response to a tectonic hazard?
Examples of long-term responses include:
Rebuilding homes.
Improving building regulations.
Repairing utilities (water and gas).
Improved drills, evacuation plans and warning systems.
Data used to predict future eruptions.
Transport routes are rebuilt.
Define the term immediate response.
An immediate response refers to actions taken:
Before a predicted hazardous event occurs.
In the days and weeks immediately after a tectonic event.
Give one example of an immediate response to an earthquake.
Examples of an immediate earthquake response include:
Search and rescue teams searching for survivors.
Medical assistance.
Providing food, water and shelter.
Recovery and burial of bodies.
Evacuation.
Define evacuation in the context of hazard responses.
Evacuation refers to moving people out of areas at risk from an impending hazard.
True or False?
One of the immediate responses after the 2015 Nepal earthquake was the introduction of earthquake drills.
False.
The introduction of earthquake drills was a long-term response after the 2015 Nepal earthquake.
What were the long-term responses in Italy after the 2016 earthquake?
Long-term responses to after the 2016 Italian earthquake included:
The €42 million 'Home Italy' initiative to rebuild homes in the same style.
Relocation of those people who were made homeless.
Children were able to attend school in nearby towns.
Building of a temporary school in Amatrice.
True or False?
One secondary effect of tectonic hazards is that food prices may increase.
True.
As a result of a tectonic hazard food prices may increase due to the decrease in supply when crops are destroyed or it is not possible to deliver food supplies to an area due to damage/destruction of the infrastructure.
By 2025, how many people are estimated to live in tectonically active areas?
It is estimated 600 million people will live in tectonically active areas by 2025.
Give two economic advantages of living near volcanoes.
Economic advantages include:
Fertile soils.
Tourism.
Mining minerals and precious stones.
Geothermal energy.
Define geothermal energy.
Geothermal energy refers to heat extracted from beneath the Earth's surface, often near volcanic areas, and used to generate power.
State a social reason why people live in hazard-prone areas.
A social reason is that people don't want to leave their family, friends and communities they have always lived in.
What does hazard mapping refer to?
Hazard mapping is using maps to identify areas at greater risk from hazards.
True or False?
It is possible to predict the timing of volcanic eruptions accurately.
False.
While monitoring allows the prediction of eruptions, accurate timings are not possible.
Give one example of how volcanoes are monitored.
Volcanoes are monitored using several methods, including:
Seismometers.
Lasers/tiltmeters.
Remote sensing.
Gas sensors.
What is the definition of an exclusion zone?
An exclusion zone is an area evacuated and which people are restricted from entering due to an impending hazard.
State an example of earthquake protection methods.
Examples of earthquake protection strategies include:
Earthquake drills.
Earthquake-resistant building design.
Sea walls to protect against tsunamis.
What is involved in hazard planning for tectonic events?
Hazard planning involves:
Evacuation plans.
Education/drills.
Stockpiling supplies.
Training emergency services.