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

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. A-LEVEL GEOGRAPHY TEACHING AND LEARNING RESOURCES

Key terms Vulnerability A high risk combined with an inability of individuals and communities to cope. A-LEVEL GEOGRAPHY TEACHING AND LEARNING RESOURCES

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. A-LEVEL GEOGRAPHY TEACHING AND LEARNING RESOURCES

Key terms Storm surge A short-term change in sea level caused by low air pressure. A-LEVEL GEOGRAPHY TEACHING AND LEARNING RESOURCES

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