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Plate Tectonics (Hazard perception - It is only by the presence of people…
Plate Tectonics
Hazard perception - It is only by the presence of people that a natural hazard becomes a hazard. Due to population and increased demand for land has resulted in building in areas that have increased risk.
human responses - the natural human response to a hazard is to reduce risk to life and equity. This involves saving possessions and safeguarding property. Therefore it globally refers to coordinating rescue and humanitarian aid. However, response times have been reduced by the development of of the Automatic Disaster Analysis and Mapping System (ADAM), this allows immediate access to the scale of the disaster, the supplies available and local infrastructure.
fatalistic approach - This means doing nothing and accepting the fact that natural hazard are a part of life and losses have to be accepted. Interference with the natural processes can have a detrimental effect on the ecosystems. We must let natural processes take their course.
prediction - due to the increase in technology, it has meant there has been an attempt to increase hazard predictions. However, advances in communications and the ability to monitor clues mean that information from all parts of the world can be shared and analysed quickly leading to a decrease in the number of those at risk.
adaptation - once there is acceptance that hazards are part of life, people can adapt their behavior to specific risks so losses are kept to a minimum. This is the most realistic method as it has proven to be effective and cost-effective for governments.
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crusts
oceanic crust - volcanoes produce lava that covers the ocean floor with rock called Basalt. it is thin and dense.
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Theory evidence - the plate tectonic theory suggests movement of the lithosphere due to convection currents and seafloor spreading and is supported by continental drift.
Types of hazards
geophysical - these are hazards driven by the earths internal energy such as volcanoes and seismic activity.
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convection currents - This is the movement of the earths mantle. As the magma in the mantle cools it sinks. It then heats up and becomes less dense. This then makes the mantle rise which forms a heat current as the magma rises towards the athenosphere. This cools the closer it gets to the outer core.
Paleomagnetism - The earths polarity switches every 400,000 years. These are magnets of the earth.
ridge push - This is at constructive boundaries. The oceanic plates are pulled apart which forms a ridge. Gravity causes the ridge to push on the lithosphere.
slab pull - This is the motion of the tectonic plate. 2 overlapping plates form a subduction fault of the lower plate and goes into the mantle. The leading edge is colder and heavier than the upper mantle so there is greater force. This then pulls the rest of the plate down as a continuous movement.
conservative collision - The plates slide past eachother, then they lock and tension builds and when they release, it causes seismic waves.
continental rifting - There is a swelling of magma that forces the crust to split, the land stretches and sinks to form a rift valley and leads to volcanic activity.
What is a hazard? - It is the threat of a substantial loss of life, substantial impact upon life or damage to property that can be caused by an event. These events can be caused by human activity or are mainly natural. However, natural events can be a consequence of human actions.
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