VOLCANOS Flashcards
(20 cards)
how many people live within 100km of a active volcano
estimated 800 million
where can active volcanos be found
constructive boundaries - Iceland
destructive boundaries - ring of fire
hot spots - Hawaiian
what scale is used to measure volcanic activity
VEI scale
what are the weakness using the VEI scale
doesn’t account for gas emissions
what is the relationship between magnitude and frequency of volcanic events
when the magnitude of the eruption increases the frequency of eruptions of the volcano decreases
what are the 4 primary effects from volcanic activity
tephra
pyroclastic flows
lava flows
volcanic gases
tephra
soil material of various sizes ranging from volcanic bombs to ash ejecting into the atmosphere
pyroclastic flows
very hot
high velocity flows made up of gas a tephra ash
Causes widespread death and destruction
travel up to 700km per hour
volcanic gases
Released into atmosphere
Can be harmful to humans and animals if breathed in
what are the 5 secondary effect
Lahars
floods
volcanic landslides
acid rain
climatic change
define Lahars - mudflows
melted snow and ice from eruption combined with volcanic ash forms mudflows that move down river valleys at high speeds
define floods after a volcanic eruption
eruptions melt glaciers and ice caps
serious flooding results
define volcanic landslides and tsunamis
sea waves generated by large volcanic eruptions
destructive and deadly
define acid rain
volcanoes emit gas which includes sulphur and then combined with moisture acid rain results
secondary effect
climatic change
ejection of huge amounts of volcanic debris into the atmosphere
can reduce climate change
how can volcanic activity be predicted
gas
ground vibrations
what are 2 ways people can be protected from volcanic events
land use planning
diversion of lava flows
diversion of lava flows in protection from volcanic activity
example
on Mt Etna in Scilly digging trenches and dropping blocks into the lava stream and using explosives has been successful in slowing down the lava flows
sea water is used to solidify lava and slow it down
land use planning in protection from volcanic activity
areas off greater risk can be identified and not built on
hazard risk assessment
responses to volcanic activity
immediate and long term
immediate lava flow- warnings, evacuations, attempts to stop
long term- monitoring research
buildings barriers in anticipation of lava flows
