contains 5x the magam
needed to make a
supervolcano = 5,000cubic
km of magma
What?
cataclismic eruption
1000+ cubic km material
(magma and pyroclastic
material)
immensely violent VEI 8
100m thick ash and tephra
less violent basaltic flood
Caldera - flat and sunken crater
When?
every 600,000 yrs
last one c.640,000 yrs ago
Where?
Yelowstone Park,
Norris Geyser Basin
2003 - increase in ground temps to 100C
/ more frequent geyser eruptions / more
gases from vents / 5 bison died of
hydrogen sulphide & carbon dioxide
poisoning / trees died / closed to public
uplift due to magma
rising or gas levels
increasing
So what?
immediate effects
extinguish all life forms withing 200km radius
further afield: transport, livestock power
lines and water affected
40-50 km high cloud of ash
equivalent to 1000 hiroshima bombs a second
more rainfall - lahars. could cause
50,000 deaths
15cm ash within 1,000km: loss of homes
/ roof colapse and 1 in 3 people die.
Ash reaches Europe in 5 days
longer term effects
onset of glaciation - winter temps drop by 1-2.5 C
fall in agricultural yield -
increase in food prices
famine
conflict
sulphurous cloak around world in 3 wks.
drop of 12C in high latitudes - permanent snow.
Tropics - drop of 15C / failure of monsoon. 40% world pop
facing starvation