Volcanic hazards - 3.1.5.3 Flashcards
Exclusion Zone
An area around a volcano established by the government to keep people safe.
Hazard Risk Mapping
A map which identifies places which will be adversely affected by a hazard
Volcano
An opening in Earth’s crust that allows molten rock from beneath the crust to reach the surface
Magma Chamber
A reservoir of magma within the earth’s crust beneath a volcano.
Composite volcano
Composite volcano
Volcanoes with steep-sided flanks due to the thick sticky lava not travelling far from the vent. Made up of layers of lava and ash. Normally very explosive due to build-up of pressure.
Shield volcano
A large volcano with shallow sides due to the runniness (low viscosity) of the lava. Not very explosive.
Basaltic lava
Lava which has low viscosity and is very runny. It has a low silica content and allows gasses to escape easily.
Rhyolitic lava
Lava has a high viscosity and is very thick. It has a high silica content and does not allow gases to escape.
Volcanic Explosive Index
The name of the scale measures how powerful a volcanic eruption is by the volume of material erupted and the eruption cloud height.
Nuee Ardent (Pyroclastic flow)
Fast-moving currents of hot gas and rock, travel away from the volcano. Very deadly.
Ash fallout
Small bits of pulverized rock called tephra cover crops, pollute water supplies, collapse houses and affect planes in flight.
Larhar
Mudflows occur when volcanic material mixes with large amounts of water
Volcanic bombs
Solidified pieces of magma and rock were thrown from the volcano.
Volcanic Gases
Volcanoes release sulphur dioxide, which when mixed with water vapour can create sulphuric acid
Acid Rain
Volcanic gases (sulphuric dioxide) can react with water vapour in the atmosphere, which then falls as sulphuric acid.
Volcanic global cooling
Volcanic ash and gases (sulphuric acid) high in the atmosphere are very effective at reflecting back sunlight and reducing solar insulation.
Geothermal Energy
Heat from the earth is used to turn water into steam to turn a turbine and create electricity.
Seismometer
An instrument that detects the vibrations caused by an earthquake (when the magma chamber is growing).
Tiltmeter
A piece of equipment is used to detect if a volcano is growing bigger by measuring the tilt of its slopes. If it gets bigger an eruption is likely.
Spectrometer
A device which measures the amount of sulphur dioxide in the gases released by a volcano. The more SOx there is, the more likely an eruption (because the magma must be near the surface).
Thermal imaging
Satellites take heat images of the volcano which record how hot the volcano is beneath the surface. The hotter it is, the closer the magma is to the surface and the more likely it will erupt.
Eyjafjallajokull
Icelandic volcano
Meltwater floods
Jakulhlaup - water released from a glacier/ice cap by the heat of a volcano.
Volcanic Ash Advisory channel
A research company tasked with determining the density of ash a plane can safely fly through.
Subglacial volcano
A volcano lies underneath an ice cap which affects the eruption intensity and the type of ash produced.
Pinatubo
Philippine volcano
Subsistence farmers
Inhabitants of LICs who grow food to eat and sell.
Asphyxiation
Ash clogs up the lungs of cattle which eventually leads to their death (1 million in the Philippines).
Shanty Town
An area of poor-quality housing lacking basic amenities. Displaced people in the Philippines lived in these.
Exclusion Zone
An area around a volcano established by the government to keep people safe.
Hazard Risk Mapping
A map which identifies places which will be adversely affected by a hazard.
Frequency
The rate at which something occurs over a particular period
Regularity
Recurring at uniform intervals
Predictability
making it possible to know in advance what to expect
Primary effect
Impacts caused directly by the hazard (the immediate damage
Secondary effect
Impacts caused by the primary effects (indirectly by the hazard) and happen after the event (the after-effects
Social
The effect of an event on people i.e. injury, disease, death etc…
Economic
The effect of an event on the economy in an area i.e. loss of income, jobs, and insurance costs etc…
Environmental
The effect of an event on the economy in an area i.e. loss of income, jobs, and insurance costs etc…
Political
The effects on the local and national government and its ability to make decisions that improve people’s quality of life i.e. spending, planning, regulations etc…
Mitigation
Reduce the severity of an event and lessen its impact. This can be done pre- and post-hazard.
Prevention
Actions aimed at stopping the natural hazard from starting.
Adaption
How people change their behaviour or surroundings to minimise the risks and maximise the benefits.
Preparedness
What happens before the natural hazard to minimise risk and vulnerability
