volcanic hazards

simply, where may volcanoes occur

• on plate boundaries where plates melt and magma erupts through a plate

• on hotspots

list some hazards associated with volcanoes

lava flows, lahars, glacial floods, tephra, toxic gases, acid rain, nuees ardentes/ pyroclastic flows

what can lava flow depend on

• lava can flow quickly depending on its viscosity

• silica makes lave viscous and slow, which is common in explosive eruptions

what are lahars and what are they caused by

• mudflows (like a muddy river)

• caused by a number of reasons, usually by melting ice at high altitudes

what are glacial floods

• when temperatures are high from magma, glaciers or ice sheets at high temperatures quickly melt and a large amount of water is discharged

what is tephra

any type of rock that is ejected by a volcano

what are toxic gases

gases released during some reactions, even CO2, can be toxic as it can replace oxygen as it is heavier

what is acid rain caused by

when gases such as sulphur dioxide are released into the atmosphere an react with rainwater

what are nuees ardentes/ pyroclastic flows

clouds of burning hot ash and gas that collapses down a volcano at high speeds.

average speeds of around 60 mph but can reach 430 mph

what is a famous area of volcanoes called

• the ring of fire

• an area of high volcanic and earthquake activity located in the Pacific, and the majority of large volcanoes occur within this 25,000 mile belt

how is vulcanicity measured

• measures using the Volcanic Explosively Index (VEI)

• the more powerful, the more explosive

what factors are included when calculating the VEI

• how much tephra is erupted

• how long it lasts

• how high the tephra is ejected

what is the opposite of an explosive reaction

an effusive reaction (calmer and lower magnitude)

depending on the frequency a volcano erupts, how can volcanoes be classified

• active, dormant, extinct

usually, what do higher frequency eruptions tell us about the eruptions

they are effusive, whereas low frequency eruptions are explosive

why can volcanic reactions be described as being regular

because the eruptions on each type of boundary are similar (e.g. eruptions on destructive boundaries will regularly be explosive)

what could signs of an imminent reaction be

• seismic activity, gases releasing, elevation

• but, there is no definite predictions to a volcanic eruption

give some primary effects of a volcanic hazard

• ecosystems damaged through various volcanic hazards, wildlife killed

• businesses and industries destroyed or disrupted

• people killed

• homes destroyed from lava/ pyroclastic flows

• government buildings and other important areas destroyed or disrupted

give some secondary effects of a volcanic hazard

• water acidified by acid rain

• volcanic gases contribute to greenhouse effect (global warming)

• jobs lost

• profit from tourism industry

• fires can start which puts lives at risk

• mudflows or floods

• trauma

• homelessness

• conflicts concerning government response, food shortages, insurance etc.

what are ways in which hazards can be responded to

• preventing them directly

• being prepared for the next hazard

• mitigating the effects

• adapting your lifestyle to limit the hazards effects

how could volcanic hazards be prevented

• they cannot be prevented.

• only the risk to people can be prevented: by not allowing people near volcanic hazards (e.g. preventing building around volcanoes)

how can you prepare for a volcanic hazard

• monitoring increases the notice of volcanic eruptions, meaning warnings can be given out

• education on volcanoes in areas of risk so people know what to do if there is a volcanic eruption

• education procedures planned

• training response teams

how can volcanic hazards be mitigated

• direct intervention to the volcano e.g. concrete blocks to steer lava away from areas at risk

• strengthening buildings that are at risk of mudflows or ash pileup

• education and exclusion zones

• mitigating effects on health by having emergency aid and rescue

how can you adapt to living with volcanic hazards

• move away from the area at risk

• capitalise on opportunities, such as encouraging tourism

• change profession so it is less likely to be affected by volcanic hazards