A pleasant morning to everyone.

Today is another good day to Extinct

start and listen to our presentation. We are The Group 1 and
we will discuss about the Volcanoes. An extinct volcano is one which has erupted thousands of
years ago, but it will probably never erupt again.
Of course we need to know Where Does the Word ‘Volcano’
Come From? Why Do Volcanoes Erupt?

Have you ever thought about why volcanoes are actually We know that the earth's crust is made up of huge slabs
called 'volcanoes'? Can you think of a reason why? called tectonic plates. These fit together like a jigsaw puzzle
and they sometimes move.
The word 'volcano' comes from the island ‘Vulcano’, which is
a volcanic island in Italy.The island actually gets its name from The movement causes friction which causes earthquakes and
the Roman god of fire – Vulcan volcanic eruptions near the edges of the plates. The theory
that explains this process is called ‘plate tectonics’ – this
The Roman God of Fire means the plates are moving in different directions and at
different speeds. Sometimes they collide or brush past each
Roman mythology says that Vulcan lived in a volcano. As well
other and cause these earthquakes and volcanic eruptions.
as being the god of fire, he made many weapons and forged
them using metal and fire. He was a very skilled blacksmith. A volcano is a vent, or opening, in the Earths's crust from
which hot rock has been ejected sometime in its history. It is
Romans believed that if Vulcan was made angry, the volcano
fueled by magma (molten rock found deep in the Earth) that
would erupt. So they tried their best to please him and not
flows upwards in fissures in the Earth’s crust. Most volcanoes
anger him.
are the size of mountains. Materials ejected by them during
Where Are Most Volcanoes Located? eruptions include lava (molten rock), ash, steam and a variety
of gases. Some eruptions are quite large, with thousands,
The ‘Ring of Fire’ is an area of the Pacific Ocean that is shaped even millions, of tons of material being ejected. There are
like a horseshoe. It is home to 90% of the world's earthquakes three main types of volcanoes: Shield Volcanoes, Cinder Cone
and 75% of the world's volcanoes Volcanoes, Composite Volcanoes
It contains a string of 452 volcanoes, which stretches from the Volcanic Landforms- on Earth, there are many different types
southern tip of South America, up along the coast of North of volcanic landforms, ranging in size and shape from
America, down through Japan, and into New Zealand. microscopic scoria cones to massive flood basalt or ignimbrite
How Are Volcanoes Formed? plateaux. The volume and composition of the magma, the
tectonic setting, the characteristics of the crust, and post-
Deep in the earth, it is extremely hot. It is so hot, in fact, that eruption erosion are all factors that affect the final volcanic
rocks actually melt and form magma, which makes up the landform. There are two types of primary volcanic landforms
mantle of the earth (pre-erosion): polygenetic volcanoes and monogenetic
volcanoes. Composite, shield, and caldera volcanoes are
The upper mantle mixes and moves, which creates pressure
examples of the former; tuff rings and cones, maars, and
underneath the crust. This pressure can sometimes cause the
kimberlites are examples of the latter; and lava domes and
mantle to leak out onto the surface of the earth
coulées are examples of the former. At the planetary scale,
geographically, chronologically, and magmatically related
Over time, as this magma leaks out, the volcano will get volcanic provinces, such as volcanic fields, volcanic arcs, and
bigger and bigger. vast igneous provinces, are the most visible volcanic
landforms. They might contain every single polygenetic and
The Three Stages of Volcanoes monogenetic volcanic landform, independent of the tectonic
setting, offering compelling evidence for main universal
Active
influences on the nature of volcanic landforms on Earth.
An active volcano is one that has erupted recently, and there
is the possibility that it may erupt again.

Dormant

A dormant volcano is one that has not erupted for a long

time, however, it may still erupt in the future.
Cinder Cone Volcanoes Now that we are done discussing about Volcanoes, here
some few questions that we prepared for you
There are the simplest type of volcano. Cinder Cone
Volcanoes have a narrow base and steep sides since they are 1. An opening on the earth surface where magma
made of cinders and other rock particles that are blown into reaches the surface
the air. The hardened pieces of lava are called cinders. Most
A. volcano
cinder cones have a bowl-shaped crater at the summit and
rarely rise more than a thousand feet or so above their
B. ring of fire
surroundings. Cinder cones are often found on the flanks of C. composite
large summit crater.
2. Where are the most active volcanoes located?
Shield Volcano
A. Roman God of fire
is a type of volcano named for its low profile,
B. Ring of fire
resembling a warrior's shield lying on the ground. It is
formed by the eruption of highly fluid C. Landforms
(low viscosity) lava, which travels farther and forms
3. What is molten rock that has formed deep within the
thinner flows than the more viscous lava erupted from
Earth?
a stratovolcano. Repeated eruptions result in the steady
accumulation of broad sheets of lava, building up the A. Lava
shield volcano's distinctive form. There are found
B. Magma
wherever fluid low-silica lava reaches the surface of a
rocky planet. However, they are most characteristic of C. Volcano
ocean island volcanism associated with hot spots or
with continental rift volcanism 4. Volcanoes are usually steep sided. They are formed
from layers of ash and lava?
Composite Volcano
A) Shield
Can be the most picturesque of all volcanoes. A classic
composite volcano is conical with a concave shape that B) Composite
is steeper near the top. These mountains commonly C) Cone
have snow-covered peaks standing high above the
surrounding mountainous terrain. Composite cones are 5. What is molten rock that has reached the Earth's
large volcanoes (many thousands of feet or meters tall) surface?
generally composed of lava flows, pyroclastic deposits, A) Magma
and mudflow (lahar) deposits, as well as lava domes.
Composite volcanoes are active over long periods (tens B) Lava
to hundreds of thousands of years), and erupt
C) Rocks
periodically. Composite volcanoes are also called
stratovolcanoes. Some geologists avoid the use of the 6. These are volcanoes that erupt and enter the period
term “stratovolcano” because these volcanoes typically of inactivity
are not stratified and do not consist of orderly layers of
A. Active
lava flows and pyroclastic deposits
B Extinct

C Dormant