Earthquakes
 An _________ is the rapid __________of the __________
These movements are caused by waves of
____________moving through the crust.
 Scientists measure seismic activity using instruments called
___________.
 The ____________ or _____________ of an earthquake can be
calculated in several different ways, but usually it is measured
using the ___________________.
Where are they found?
What causes them?
What is this and what does it do ?