Page 91 - (DK) I Can’t Believe It! 2

STRANGE BUT TRUE! 89

Close relations of hot springs and
gushing geysers, fumaroles require FAST FACTS
heat and a gas or water source to burst
forth. Volcanic magma (molten rock) These steaming vents in Earth’s
under Earth’s surface provides the heat surface always occur in regions with
and gases. When magma comes into active volcanism. They work in a similar
contact with groundwater, the water way to geysers: Underground water
boils and is released as steam. meets magma and is heated until it
boils and bursts through cracks in the
rock, making its way to the surface.
A fumarole has a smaller reserve
of water so emits only steam.

Volcanic
eruption Fumarole
Gas can be
released for
centuries or just
a few weeks,
depending on Heated
the heat groundwater
source.
Crack
Magma

In Arctic areas, the
exiting steam freezes,
forming vast snow
chimneys around the
volcanic opening.

US_088-089_309600_Snow_chimneys.indd 89 19/12/17 12:56 pm