1. Key terms Risk The exposure of people to a
hazardous event. More specifically, it is
the probability of a hazard occurring that
leads to the loss of lives and/or livelihood.
A-LEVEL GEOGRAPHY TEACHING AND LEARNING RESOURCES

2. Key terms Hazard ‘A perceived natural/geophysical event that has
the potential to threaten both life and property’ (Whittow).
Yet a geophysical hazard event would not be such without,
for example, people at or near its location. That is to say,
earthquakes would not be hazards if people did not live in
buildings that collapse as a result of ground shaking. Many
hazards occur at the interface between natural and human
systems.
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3. Key terms Vulnerability
A high risk combined with an inability of individuals and communities to cope.
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4. Key terms Volcanic Explosivity Index (VEI)
A relative measure of the explosiveness of a volcanic eruption, which is calculated from the volume of products (ejecta), height of the eruption cloud and qualitative observations. Like the Richter Scale and MMS, the VEI is logarithmic: an increase of one index indicates an eruption that is ten times as powerful.
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5. Key terms
Storm surge
A short-term change in sea level caused by low air pressure.
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6. Key terms Magnitude The magnitude of an earthquake is related
to the amount of movement, or displacement, in the fault,
which is in turn a measure of energy release. The 2004
earthquake in Indonesia was very large (M = 9.3) because
a large vertical displacement (15 m) occurred along a very
long fault distance, approximately 1500 km. (Earthquake
magnitude is measured at the epicentre, the point on the
Earth’s surface directly above the hypocentre.)
A-LEVEL GEOGRAPHY TEACHING AND LEARNING RESOURCES