Tectonic Hazards Flashcards
What is a natural hazard?
Any natural events that have the potential to endanger human life, the economy and property. They are major risks and result in death and destruction.
What is a hazard risk?
The chance of being affected by a natural hazard
How many classes for natural hazards are there?
4
What is an atmospheric Hazard?
They are created in the atmosphere, caused by the movement of air and water. Eg forest fires, hurricanes tornadoes and floods
What is a terrestrial Hazard?
Made by the movement of the earth tectonic plates or surfaced rock (soil). Eg volcanoes, earthquakes and tsunamis
What is a water-based Hazard?
Created by rivers seas or oceans. e.g coastal flooding and floods
What is a biological Hazard?
Any biological substances that pose a threat to the health of people. Eg diseases such as ebola and covid-19
What are the factors that increase the risk of a hazard occurring?
1 urbanisation: densely populated urban areas concentrate those at risk
2 poverty: expense of housing leads to building on risky ground
3 farming: the attraction of nutrient rich floodplains put people at risk
4 climate change: global warming raises sea levels and generates more extreme weather
Where do earthquakes in volcanos occur?
At the margins of slow moving tectonic plates and plate boundaries
What are the different types of crust on the earth?
- Dense, thin oceanic crust
- Less dense, thicker continental crust
Why do earthquakes and volcanic eruptions occur?
They are the result of physical processes.
Friction and sticking between plates creates enormous pressure and stress which builds to a breaking point.
Plates move driven by confection currents within the mantle and undergravity.
Where do volcanoes occur?
Volcanoes occur in belts a long plate margins, for example Pacific ring of fire and the mid Atlantic ridge. But some occur at ‘hotspots’ thin crust breaks and magma breaks through the surface, eg Hawaiian Islands
How many plate margins are there?
4
What is a constructive margin? (tensional, divergent)
When two plates move apart from each other and magma forces its way to the surface (continental crust). Volcanoes are formed. For example: Volcanic Islands, Mid Atlantic Ridge, Iceland. South America, North America, African and Eurasian plate
What is a conservative margin? (transform)
When two plates move past each other at different rates. They slide past each other in the opposite or same direction at different speeds. There are no volcanoes because there is no magma. They trigger earthquakes when they slip. For example: San Andreas Fault,California. North America.
