natural hazards Flashcards
what are the three types of tectonic plate?
convergent (destructive/collision)- the move towards each other, where one subducts under the other.
divergent (constructive)-moving apart from each other
conservative- sliding past ne another.
why do plate tectonic move?
plate tectonic move due to convention currents, which is the circulation of heat in the mantle, hotter mantle rises and cooler mantle sinks, this movement is strong enough to move the plates.
why are earthquakes created?
earthquakes are created due to the movement of currents in the mantle that cause the plates to move, as they move pressure is built which is eventually released creating an earthquake.
what proves do we have that the plates move?
- continents where once together. fossil from the same species of animals have been found in various countries that proves this theory, along with the fact that the same rock type can be found in various glaciers around the world which once again proves the theory that continents were once together.
- middle ocean ridges prove it
what has changed since the 1960’s?
- the number of hazards have increased
- number of fatalities have decreases but the number of mega disaster have increased.
- the total cost associated with hazards has increased significantly
- population growth have caused the number of people being affected by hazards to increase.
can you name the four types of seismic waves?
- primary: the fastest, travel through solid and liquid.
- secondary : nearly half of the speed of primary waves and can only travel through solid.
- love: they are closer to the ground.
- Rayleigh: the slowest moving wave.
what factors can make a location vulnerable?
geographical location geology education durability of buildings mitigation
what is the difference between an hazard and a disaster?
The united nation identifies a disaster as being an hazard that affects more than 100 individuals or that kills more than 10 people.
A natural hazard is a natural event that threats human lives.
