natural hazards and tectonuc plates Flashcards
what is a natural hazard
when a natural event has the possibility of harming human life and/or property
natural disaster
when a natural hazard actually happens and causes significant damage to a vulnerable population
natural event
a naturally occuring physical occurance
what are the two types of hazards
geophysical and hyrdrometeorological
what is a geophysical hazard
a hazard that occurs due to the movement of tectonic plates
What is a hydrometeorological Hazard?
A hazard involving water and weather systems
Give some examples of geophysical hazards
Floods, droughts, heatwaves , tropical storms, such as typhoons hurricanes in cyclones storms and wildfires
What are the factors affecting hazard risk?
Time location, frequency, magnitude type of Hazard, population, government, wealth 
What state are the four layers of the Earth? 
The inner core is solid. The outer core is liquid. The mantle is semi solid and the crust is solid.
What are convection currents?
- Radioactive decay in the cool causes magma in mantle to heat up
- It rises as the density decreases
- When it reaches the crust, it moves away from the heat and spreads out, and then cools down and sinks backed down 
- The convection cycle continues
What is slab pull
Slab pull is when two plates meet, and one sinks under the other, the slab pull causes the rest of the plate to go down
which type of crust is thinner and denser
oceanic is thinner and denser than continental
what happens at a constructive boundary
plates move away from each other and new crust is formed as magma rises
what are the hazards at constructive boundaries
The hazards are shield volcanoes and undersea volcanoes. there are also earthquakes due to the gentle extension, but they are not very severe
what is formed at constructive boundaries
ridges and islands
describe what happens at destructive subduction boundaries
the denser plate subducts under the less dense plate. This is usually the oceanic plate under the continental plate, but subduction also happens when there are two oceanic plates. Subducting plates pulled into the mantle by slab pull. As the plate subducts, it melts due to friction and high temperatures
what are the hazards at destructive boundaries
Composite volcanoes are created at destructive boundaries. The subduction involves collision and friction, so causes very severe earthquakes.
What is created at destructive boundaries?
trenches are created. oceanic plate being forced onto another oceanic plate makes island arcs. when the continental plate buckles upwards mountains are made
describe what happens in a destruction collision boundary
between two continental plates. both move upward and make fold mountains. rift valleys also created
what is a conservative boundary
when two plates slide past each other in opposite directions or differnt speeds. nothing is created or destroyed
hazards at conservative boundaries
moderate earthquakes but close to the surface. no volcanoes