Exam Revision - Natural hazards Flashcards
(42 cards)
What is a natural hazard?
A physical process of event which has the potential to cause loss of life and damage to property
What is a climatic hazard?
Hazards caused by weather
What is tectonic hazards?
Hazards caused by tectonic plates eg volcanoes earthquakes
What is the theory of plate tectonics?
The earths crust is not complete like the skin of an orange. It is broken into several individual pieces called tectonic plates. These plates can be thought of as floating on the semi-liquid mantle below.
Where are volcanoes found / earthquakes occur?
On or near plate boundaries.
What are geomorphological hazards?
Hazards caused by the ground.
What is a constructive plate margin?
Plates that are moving away from each other.
What is a destructive plate margin?
Plates that move towards each other.
+The oceanic crust subducts underneath the continental crust - called the subduction zone.
+When two continental plates meet, ground is folded and forced upwards to create mountains.
What is a conservative plate margin?
Plates that slide past each other [or in the same direction at different speeds]
+Crust isn’t created nor destroyed.
What are the causes of earthquakes?
+Convection currents in mantle cause plates to move
+Plates are jagged - plates lock
+ Pressure builds up - a sudden release of energy occurs.
+Seismic waves released - earthquake occurs.
How is a composite volcano made?
+By destructive plate margins
How is a shield volcano made?
+By constructive plate margins
What are the primary effects of earthquakes/volcanoes
+Buildings collapse
+People are injured or killed by falling masonry.
+Roads, railways, ports are damaged.
+Electricity cables, gas and water pipes are damaged, cutting of supplies.
Why do people live in areas of risk from earthquakes/volcanoes?
+Fertile soils - volcanic ash is rich in nutrients.
+Geothermal energy - good for increasing renewable energy use - economical & efficient
+Tourism - attracts people who enjoy dramatic scenery
What are the secondary impacts of earthquakes/volcanoes.
+They can trigger landslides and tsunamis - which can destroy more buildings.
+People left homeless - could die from hypothermia
+Shortage of clean water and sanitation - diseases cold spread.
+Blocked/destroyed roads - leads to blocking emergency vehicles
+Businesses destroyed - leads to lack of income and unemployment.
+Repairs can be expensive - weakens a country’s economy.
What are the immediate responses to earthquakes/volcanoes?
+Rescue people
+Recover dead bodies to prevent spread of disease
+Set up temporary shelters
+Provide temporary supplies - water, food first aid.
+NGOs could assist in helping or foreign governments.
What are the long-term responses to earthquakes/volcanoes?
+Rehousing
+Repair damaged buildings, roads, railways, bridges etc.
+Improve building regulations - so they can be more earthquake resistant to damage,
+Reconnect broken pipes, electricity etc.
How did the Haiti earthquake affect the people?
3 million people affected. Over 220,000 deaths. 300,000 injured. 1.3 million made homeless. Several hospitals collapsed. 7 on the Richter scale [9] on mercalli
What was the cause of the Christchurch earthquake?
The 6.3 magnitude earthquake struck New Zealand at 12:51 on 22 February 2011. The epicentre was 6 miles South East of Christchurch and the focus was very shallow at 3.1 miles. The earthquake occurred on a conservative plate margin where the Pacific Plate slid past the Australian Plate in the opposite direction. It was technically an aftershock from a larger earthquake in 2010 but the impacts were more severe.
How did the Christchurch earthquake affect the people?
181 people were killed and around 2,000 people were injured.
Hundreds of kilometres of water and sewage pipes were damaged
80% of the city was without electricity
6.3 on Richter scale
How did Christchurch respond to the earthquakes?
They were well equipped
+Their emergency services were well trained
+They put stricter building codes in place - eg deeper foundations, flexible materials
+made earthquake proof buildings and roads.
+proven to be very effective
How did Haiti respond to the earthquakes?
Neighbouring Dominican Republic provided emergency water and medical supplies as well as heavy machinery to help with search and rescue underneath the rubble, but most people were left to dig through the rubble by hand.
Medical teams began treating the injured – temporary field hospitals were set up by organisations like the International Committee of the Red Cross.
What are three types of natural hazards?
+Climatic hazards
+Tectonic hazards
+Geomorphological hazards
What is a natural disaster?
A natural hazard that has already happened
