VOLCANOES
May 18, 2015
VOLCANOES
What is it a volcano?
A volcano is like a chimney in the Earth’s crust
(surface) where magma flows out.
Eruption
In 1883, in Indonesia, a volcano called Krakatoa erupted at first.
Krakatoa
The inside of the Earth is very hot, and some of the solid rock melts to form hot, liquid rock called magma.
The hole of the volcano is called vent.
When magma leaves the vent it becomes lava.
The life of a volcano
Inside a volcano
Vent
Hard lava
Magma chamber
Magma
The Earth
The theory called plate tectonics explains
how volcanoes form.
Some volcanoes form above a hot spot, which is
a very hot place in the mantle.
A volcanic eruption
Contents: gas, dust, water vapour, lava and ash
Gas, dust and water vapour
Vent
Lava
Magma
Magma chamber
Layers of lava and ash
Types of volcano
Scientists put volcanoes into three groups:
1. An Active volcano is one that is erupting or will soon erupt.
2. A Dormant volcano is one that has not erupted for a long time.
3. An Extinct volcano is one that has not erupted for more than 10.000 years.
Are in many places in the world, in many
different shapes and sizes.
TYPES OF VOLCANOES:Fissure volcano, Shield volcano, Dome volcano, Ash-cinder volcano, Composite volcano and Caldera volcano.
Volcanic landforms
Rocks and lava
Volcanoes produce lava and rocks we find
on the Earth’s Surface. Magma forms igneous
rocks. These fragments are called tephra.
Bomb Lapilli
Types of tephra
Ash Dust
Liquid lava flows fast and form smooth folds that
look like rope this is called pahoehoe.When slow, sticky lava gets hard, it forms
rocks with sharp edges; it’s called aa.Sometimes lava forms long, thing strings like
human hair this are called Pele’s hair.
Underwater volcanoes
The floor of the ocean is similar to dry land.
There are flat plains, mountain ridges, canyons and trenches in the ocean
floor.There are more volcanoes under the
ocean than on the land.
Living with volcanoes
The minerals and chemicals in the lava and ash make
soil fertile so it’s good for farming.Volcanoes also produce electricity. This electricity is called geothermal energy and the people use it.
VolcanologistsSpecial scientists are called
volcanologists. They study volcanoes in different
ways. This helps to learn about the volcano’s
history and to know what it is going to do.
Volcanologist’s suit
Laura GARRIGA SAGALÉS
Laia GONZÀLEZ TORNER
2on C.C.S.E.P.
CURS: 2008-2009