Natural Hazards Flashcards
(289 cards)
what is a natural hazard
a natural hazard is a natural event that threatens people or has the potential to cause damage destruction and death
what is an atmospheric hazard
this is created in the atmosphere by the movement of air and water weather
what is a geological hazard
this is created by the movement of the earths tectonic plates or surface rocks and soil tectonics
what is a hydro logical hazard
this is created by rivers seas or oceans
what is a risk
this is the chance of probability of being affected by natural event. People who chose to live close to a river may be at risk
what is vulnerability
how susceptible a population to the damage
what factors increase the risk from a natural hazards
in poor parts of the world poverty may force people to live in risky areas
when a river floods it deposits fertile sits on its floodplain
over 50 percent of the worlds population now live in city’s
in a warmer world the atmosphere will have more energy leading yo more intense storms
what is the structure of the earth
its made of four layers the inner core, outer core, mantle, crust
what is the inner core
the inner core is solid made of iron + nickle it is 1260 km thick and 6000 degrees
what are the characteristics of the outer core
2220 k + 4400 degrees
what are the characteristics of the mantle
2900 km and 500-900 degrees
what are the characteristics of the crust
the crust is 8-56 km thick made of hard rock
what are the two types of crust
oceanic and continental
what are the characteristics of the oceanic crust
5-10 km
more dense than the continental
subbducts and destroyed when made by continental crust
less than 200 million years old
what are the characteristics of the continental crust
20-70 km thick
less dense than the oceanic
cannot be destroyed
up to 3.8 billion years old
what is the plate tectonic theory
in 1912 Alfred Wagner proposed the theory of continental drift. he stated that the continental were slowly drifting apart around the earth
how do the continents fit together
the continents fit together like a jigsaw to form a super continent called Pangaea. this slowly split up over 250 million into 2 continents Gondwanaland and Laurasia and family’s it is today
how did Alfred Wigner prove his theory of continental drift
he did this by tarveling across the world to find similarities in the fossils he found
how is the molten magma heated
it is heated by convection currents which occur inside the mantle this is caused by the rising heat from the core. as the currents move the magma it cools on the crust and drags it causing movement of tectonic plates
what are the names of all of the tectonic plates
north american
south american
pacific plate
Nazca plate
African plate
Eurasian plate
indo Australian plate
what is an earthquake
a sudden or violent movement within the earth crust
what is a plate margin
the border between tectonic plates
where are earthquakes and volcanoes usually distributed
they are found on plate margins specifically the right hand side of the Eurasian going down the indo Australian
what is the moment magnitude scale
The Moment Magnitude Scale measures the amount of energy released by an earthquake event. It is calculated using a formula that includes the rigidity of the rock affected, the distance moved and the size of the area where movement takes place.it is measured on a scale from 1-8 being a bad earthquake