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Presented by
Rana Faizan Saleem
Roll.No (10)
VOLCANOES AND ITS
LANDFORMS
THIS PRESENTATION EXPLAINS
YOU
Volcanoes
 Structure of a Volcano
 Volcanism and its Types
 Types of Volcanoes
 Landforms from Lava
 Landforms from Magma
 Benefits of Volcanoes

VOLCANOES
Introduction:
Word Volcano taken from: Roman god of fire,
Vulcan
What is a Volcano?

Volcano – a weak spot in the earth’s crust
where molten material (magma), comes to
the surface.
How do Volcanoes formed?

When rock from the mantle melts, moves to the
surface through the crust, and releases pent-up
gases, volcanoes erupt.

Extremely high temperature and pressure cause
the rock to melt and become liquid rock or magma.
When a large body of magma has formed, it rises
through the denser rock layers toward Earth's
surface.
WHAT HAPPENS AS A
VOLCANO ERUPTS?

As magma rises toward the surface, the pressure
decreases allowing the dissolved gases to separate out
forming bubbles

These materials erupts:
i.
ii.
iii.
Lava:(Liquid)
Volcanic Ash:(The Solid)
Volcanic Bomb: (Like Ash but large)
STRUCTURE OF A VOLCANO

Magma:
Molten mixture of rock-forming substances, gases, and water
from the mantle.

Lava:
When magma reaches the surface it is called Lava.

Magma Chamber:
The pocket beneath a volcano where magma collects

Conduit Pipe:
A long tube through which magma moves from the magma
chamber to the Earth’s surface

Vent:
An opening where magma and gas leave the volcano

Crater:
Mouth of a volcano - surrounds a volcanic vent.

Throat:
Entrance of a volcano. The part of the conduit that ejects lava and
volcanic ash.

Flank:
The side of a Volcano

Lava flow:
A lava flow is basically a stream of lava on the surface.

Summit:
Highest point

Ash:
Fragments of lava or rock smaller than 2 mm in size that are blasted
into the air by volcanic explosions.

Ash Cloud:

A cloud of ash formed by volcanic explosions.
Parasitic Cone:
A small cone-shaped volcano formed by an accumulation of volcanic
debris.
VOLCANISM AND ITS TYPES
Volcanism:
When hot molten magma escapes from the Earth’s core
becoming cooler, and forming hard rocks, we refer to this process
as volcanism. Volcanism takes place both above the surface of
Earth, as well as beneath its surface.

Extrusive Volcanism
When molten lava escapes the Earth and reaches the surface
geologists say that it is extrusive volcanism.

Intrusive Volcanism
When molten magma cools and hardens beneath the surface of
the Earth, we say that it is intrusive volcanism.
VOLCANIC LANDFORMS
TYPES ON THE BASIS OF ERUPTION

Active Volcano:
An active volcano is a volcano that erupts regularly.
about 1510 active volcanoes in the world.
(Pacific Ring of Fire):- The ring of fire is a circle around the edges
of the pacific ocean where half the worlds valcanoes are located
.


Dormant Volcano:
A dormant volcano is a volcano that is not erupting, but
supposed to erupt again.
Extinct Volcano:
An extinct volcano has not had an eruption and is not expected
to erupt again.
TYPES ON THE BASIS OF SHAPES
Following types on Shape basis:
Sheild Volcano
 Composite (or Stratovolcano)
 Cinder Cones
 Lava Dome

Sheild Volcano:

A bowl or sheild shaped Volcano in the
middle with long-gentle slopes made by
basaltic lava flows,called flood basalt.

Shield volcanoes created the Hawaiian
Islands
HAWAIIAN ISLAND
Composite Volcano:


A composite volcano is built up from
alternate layers of ash, high viscosity lava
and
rock debris.
It has steep sides because when it erupts it
lava is thick and viscous meaning that it
does not travel great distances and stays on
the side of the volcano.
MOUNT FUJI
Cinder Cones:

Erupts violently

Cinder cones form around a volcanic vent.
Lava explodes into the air and cools very
quickly forming accumulating a ring of
volcanic fragments.
Lava Dome:




A dome volcano is a round shaped mountain
made of viscous lava.
The lava has a high silica content that
prevents the lava from flowing very far from
its vent.
Most domes are formed by dacite and
rhyolite lavas.
Mount Myoko Japan is example.
LANDFORMS FROM LAVA

Lava Plateau:
A lava plateau is a plateau formed by low-viscous
lava through numerous vents, during quiet
eruptions.

Caldera:
The main volcano vent dries out and the top of
the volcano collapses into it.

Volcanic Neck:
A volcanic neck forms when the magma inside a
volcano turns into rock and the outside of a volcano
wears away, leaving the spiky-shaped rock magma
LAVA PLATEAU
CALDERA
LANDFORMS FROM MAGMA

Dike:
Magma hardens in a vertical crack

Sill:
Magma hardens in a horizontal crack

Batholith:
A large deposit of magma that cools
underground.
BENEFITS OF VOLCANOES
Benefits of volcanoes

Soils

Energy from heat

Rock (Pumice)

Gases for industry