Goegrsojy Flashcards
What is a natural hazard?
Natural hazards are extreme natural events that can cause loss of life, extreme damage to property and disrupt human activities.
How does magnitude of a hazard affect the risk to people?
The greater the force of the hazard the more likely it is the hazard will have a greater impact on people. This is how often the hazard occurs. Larger, more devastating earthquakes are rare whereas floods can occur annually.
What is the difference between a primary and secondary effect?
Primary effects are things that happen immediately as a result of a hazard.
Secondary effects are things that happen in the hours, days and weeks after the initial hazard.
Give one immediate and one long term response to a natural hazard.
Short-term responses mainly involve evacuation, search and rescue and providing aid to those affected.
Long-term responses go on for months and years after a disaster. It involves constructing destroyed houses, schools, hospitals, etc. It also involves taking steps to boost the local economy.
Describe the structure of the earth.
The structure of the Earth
The three layers, starting from the outside, are: the crust – the rocky outer layer. the mantle – the semi-solid middle layer. the core - the innermost layer which is divided into an inner core and outer core.
What is a plate margin?
Earth’s tectonic plates are moving. The place where two tectonic plates meet is known as a plate margin (or boundary).
How does the crust move?
1.Collision.
2.Subduction.
3.Spreading.
4.Transform faulting.
What happens at a destructive plate margin?
Destructive plate margins
The oceanic crust is forced to sink back into the mantle, whilst the continental crust rises above. Volcanoes and earthquakes are found here. usually involves an oceanic plate and a continental plate. The plates move towards one another and this movement can cause earthquakes.
What happens at a constructive plate margin?
At a constructive plate margin. the plates move apart from one another. When this happens the magma from the mantle rises up to make (or construct) new land in the form of a shield volcano. The movement of the plates over the mantle can cause earthquakes.
What happens at a conservative plate margin?
At a conservative plate margin the plates are moving past each other or move side by side at different speeds, like cars on a road. As the plates move, friction occurs and they become stuck. The plates are still trying to move so pressures and stresses build up in the crust.
At which type of plate margin can earthquakes occur at?
Earthquakes can be found at all three plate margins. Volcanoes only form at destructive and constructive margins - they don’t form at conservative margins as there is no rising magma. You can find earthquakes and volcanoes on the land and in the sea.
Give an example of an earthquake in a HIC.
Chile.
Describe two effects and two responses to this earthquake.
Primary-500 deaths.
Secondary-Landslides blocked roads.
Immediate-Repair highway in 24hours.
Long-term-Managed to rebuild in a few months.
Give an example of an earthquake in an LIC.
Nepal.
Describe two effects and two responses to this earthquake.
Primary-Over 8,000 deaths.
Secondary-
Immediate-
Long-term-
Why do people live in areas prone to tectonic hazards?
How can tectonic hazards be managed?
