Page 29 - Super Earth Encyclopedia
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CALDERAS
A volcano that does not erupt for centuries often has a
blocked crater. It builds up pressure below the blockage until
it blows it into the sky in a massive eruption. This empties the
magma chamber inside the volcano, so its unsupported peak
collapses into the empty space. The result is a broad caldera
that is much wider than the original crater.
MOUNT ST HELENS
This stratovolcano in the USA used to have a cone-shaped peak. But in
May 1980 a catastrophic eruption made the top of the volcano cave
in, forming a caldera. A new volcanic cone is growing inside the caldera.
SUPERVOLCANOES
The biggest, most dangerous volcanoes erupt with such
shattering force that all the debris is blown far away. This
means that there is no cone, and the only clear evidence
may be a huge caldera that forms a water-filled lake,
Fissure volcano often dotted with hot springs. The eruptions of such
In rift zones, liquid lava may well up Flood basalt supervolcanoes in the past have devastated life on Earth.
from a fissure in the crust and flow Erupting lava
away in a flood of molten rock.
When the lava hardens, it forms
a flat sheet called a flood basalt.
HOLUHRAUN
The ribbon of fiery lava erupting from
this Icelandic fissure created a lava Fissure
field covering 33 sq miles (85 sq km). in crust
UNIQUE EARTH
TOBA SUPERVOLCANO
Lake Toba in Indonesia is a gigantic caldera created by the biggest
known volcanic eruption in the last 2 million years. Its central
island has been pushed up by magma pressure.
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