knowledge test Flashcards
what is a natural hazard?
a naturally occuring event that poses risk to people and property.
state one factor which affects hazard risk
time of day
what is the fatalistic approach?
if it happens, it happens. live with it.
how thick is the oceanic crust?
6-10km
what type of rock is continental crust predominantly made from?
granite
give an example of a constructive plate margin
mid atlantic ridge
what type of volcanoes are formed at constructive margins
shield volcanoes
at a destructive plate margin what does the term “subduction” refer to?
when the denser oceanic plate sinks under the continental plate and into the mantle
state two tectonic features found at a destructive plate margin
ocean trench, composite volcanoes
give an example of a conservative plate margin
san andreas fault
what is the focus of an earthquake?
the point underneath the earths surface where pressure builds up and is released
what is the epicentre of an earthquake?
the point directly above the focus, on the earth’s surface
which seismic waves cause sideways movement
secondary waves
how many times larger is a magnitude 7 earthquake compared to a magnitude 5?
100 times larger
how does the Mercalli scale measure earthquakes?
it measures the visual damage
