Tectonic Hazards Flashcards
What is a natural hazard?
A physics event that threatens people or has the potential to cause damage, destruction or death.
What is hazard risk?
The chance or probability of being affected by a natural event.
What does TEA stand for in terms of distribution questions?
Trend
Evidence
Anomaly
What are the two types of tectonic plates?
Continental and oceanic.
What is heavier, oceanic or continental?
Oceanic is dense and thin, where as continental is light and thick.
What evidence is there for continental drift?
Jigsaw theory - coastlines of continents fit together.
Fossil correlation between far apart continents
Rock and mountain correlation.
Where do constructive plate margins occur? Give an example.
Occur between two similar plate boundaries. They pull apart.
Two oceanic - Between North American and Eurasian plates.
What is formed at constructive plate boundaries?
In ocean - oceanic ridge forms where the magma is forced through the gap due to the pressure. E.g. Mid-Atlantic Ridge.
In land - rift valley.
What type of volcano is formed at a constructive plate margin?
Shield volcano - flat volcanoes with runny lava.
Where do destructive plate margins occur?
Occur between a oceanic plate and a continental plate.
What happens at a destructive plate margin?
The oceanic and constructive plates converge and the oceanic subducts under the continental because it is more dense.
How do earthquakes occur at destructive plate margins? Answer in terms of the ‘stick and slip’ process.
As the oceanic crust subducts under the continental crust, the oceanic crust gets stuck due to the friction between the plates. When this pressure is eventually released, a large earthquake can occur.
What landforms form at destructive plate margins?
Fold mountains
Deep ocean trenches
Composite cone volcanoes where magma is forced up due to the pressure.
Give an example of a destructive plate margin in the world.
Between the Nazca plates and South American plate. The Andes are an example of fold mountains and
What is a conservative plate margin?
Two plates move parallel to each other, either at different speeds or in different directions.
The friction of these plates causes seismic activity to build up and earthquakes occur here.
An example is San Andreas Fault line
When did L’Aquila occur?
6th April 2009
What was the magnitude of L’Aquila?
6.3 on the Richter scale
What were the primary effects of L’Aquila?
10,000 -15,000 buildings collapsed
308 people died
1,500 injured
Several buildings in the university were destroyed.
Many historical buildings and churches were destroyed.
What were the secondary effects of L’Aquila?
House prices and rents increased due to lack of housing
Much of the CBD was cordoned off reducing business and income
Aftershocks triggered landslides and rockfalls causing damage
Cost of repairs estimated at 4 billion euros
Landslide and mudflow caused by a burst main water supply pipeline.
What were the secondary effects of L’Aquila?
House prices and rents increased due to lack of housing
Much of the CBD was cordoned off reducing business and income
Aftershocks triggered landslides and rockfalls causing damage
Cost of repairs estimated at 4 billion euros
Landslide and mudflow caused by a burst main water supply pipeline.
What were the short term responses to L’Aquila?
Train carriages and some of the president’s homes used as temporary shelter
£171,000 raised by British Red Cross
Italian Red Cross searching for survivors within an hour
Hotels provided shelter for 10,000 and 40,000 tents given out.
7 dog units
Declared a state of emergency which sped up international aid from US and EU.
What were the long term responses to L’Aquila?
Free services - mobile, post, TV, mortgages, electricity and gas
University students exempt from taxes and university fees for 3 years.
552 million Euros granted from EU to begin rebuilding
When and where did the Ghorka earthquake occur?
April 2015 - near Kathmandu, Nepal
What magnitude was the earthquake at Ghorka?
7.8
What were the immediate effects of the earthquake at Ghorka?
Over 8,500 deaths and over a million people made homeless
352 aftershocks
Over 500,000 homes destroyed
Reduced supply of food, water and electricity.
What were the long term responses to L’Aquila?
Mortgages, TV bills, electricity, gas bills were suspended
Free public transport, and tax and university fee exemption for students
Free mobile calls
$552 million granted by EU for the rebuilding
When and where was the Ghorka earthquake? What magnitude was it?
Kathmandu, Nepal in April 2015
7.8 magnitude
What were the primary effects of the Ghorka earthquake?
Historic sites and temples destroyed eg. Dharahara tower
Over 8500 deaths and 500,000 homes destroyed
1 million people made homeless
Reduced supply of water, food and electricity
352 aftershocks
What were the secondary effects of Ghorka?
Avalanche struck Mount Everest base camp killing 19 people
Landslides in Langtang valley destroying the village
Loss of tourism harming by the economy
3% more of population pushed into poverty
Food shortages due to rice being destroyed in homes
Helicopter crash killing 6 US Marines
What were the immediate responses to Ghorka?
Hospitals were overwhelmed
Army called to help
Free phone calls
Helicopter rescue teams on Mount Everest
180 climbers rescued
What were the long term responses to Ghorka?
$274 million aid committed to recovery in Nepal
Climbing permits extended so more tourism benefitting the economy
Historical sites reopened
What are the 4 main reasons people live in areas prone to tectonic hazards
Agriculture - soil is naturally fertile and naturally irrigated (good at retaining soil)near volcanoes and rocks are rich in minerals
Mining - rising magma contains lots of minerals such as tin, silver, gold and diamonds can be found near volcanoes
Geothermal energy - heat energy can be harnessed from earth and used to provide energy to homes - Iceland uses 65% geothermal energy
Tourism - places such as Yellowstone National Park and Naples attract millions of tourists per year benefitting the economy
What are the three Ps used for reducing the risk of tectonic hazards?
Prediction - tiltmeter which measures bulge in a volcano, seismograph lane monitoring sulphur dioxide activities
Preparation- furniture and objects fastened down, earthquake drills, awareness
Protection - retro fitting homes with fire resistant materials, buildings have rolling weights on top, shatter resistant glass
