Volcanic Hazards (AQA A Level Geography)

Volcanoes can be monitored by considering the seismic activity and the amount of gases being released. Infrared cameras can also be used to detect magma movement.

A logarithmic scale where the energy release is proportional to the scale of the event. Each unit of increase on the scale equates to approximately 30 times the increase in energy, mainly felt through vibration.

A qualitative scale which measures the impact of the event. The scale has 12 points. At each point there is a description which increases in severity through to total destruction.

A logarithmic scale which offers an indication of the explosiveness of events. It is a way of classifying events by volume of material produced and frequency of events.

The nuée ardente can be sprayed with sea water. This dramatically reduces the temperature of the gases contained within the cloud, leading to significantly reduced risk.

Lahars can be controlled by geological surveys and drilling to stabilise hillslopes in affected areas. This reduces the likelihood of rockfall.

In certain types of eruptions, lava can be safely channelled away from places of high risk. This can be achieved using explosives and artificially dug channels.

Liquefaction can be managed by geological surveys which can be used to create hazard maps. These maps can then be used by planners to create exclusion zones.