1. Understanding Volcanoes

2. What is a volcano?
Volcano is an opening
in the earth’s crust
where lava, pyroclasts
and gasses are ejected
onto the surface
during eruptions.
Mt. Mayon
Mt. Kilauea
Mt. Vesuvius

3. Parts of a Volcano
 Cone- the most
prominent part of a
volcano
-formed by
the mountainous
accumulation of
volcanic materials
Mt. Mayon

4. Parts of a Volcano
 Crater- a steeped-wall
*Caldera-a very large
depression at the peak of crater that can
the volcano and the
exceed for about 1
volcanic vent.
km in diameter; they
are formed when the
summit of the
volcano collapses
during violent or
explosive eruptions.

5. Lava vs. Magma
Magma are molten rocks found
beneath the earth’s surface.
Lava are molten rocks that flowed
out of the earth’s surface.

6. Kinds of Volcano according to
Shape and Composition
 Cinder cone volcano- made up of
loose fragments called cinders
(pyroclasts and tephra)
-it is formed from
explosive eruption.
-it has a narrow base
and a steep slope
Examples: Sunset Crater in
Arizona, Mt. Pelee’ in the East
Indies

7. Kinds of Volcano according to
Shape and Composition
 Shield cone volcano- has a
wide base with gently
sloping sides. It is made
up purely of solidified
lava.
Examples: Mauna Kea
and Kilauea Volcano in
Hawaii, Olympus Mons in
Mars

8. Kinds of Volcano according to
Shape and Composition
 Composite Volcano- composed
of alternating layers of lava and
cinders. It is formed when
volcanic eruptions vary
between quiet and violent and
explosive.
Examples: Mt. Fuji in Japan, Mt.
Vesuvius and Mt. Stromboli in
Italy and Mt. Mayon in the
Philippines

9. Kinds of Volcano according to Activity
Active
Dormant/Inactive
Extinct

10. Kinds of Volcanic Eruption
 Violent or Plinian Eruption

11. Kinds of Volcanic Eruption
 Non-explosive or Quiet Eruption

12. Benefits of Volcanic Eruption
agricultural benefits
 energy benefits
industrial benefits
tourism and recreational
benefits

13. Dangers of Volcanic Eruption
volcanic gasses
 lava flows
 lahar
 global warming

14. Before a Volcanic Eruption

15. During a Volcanic Eruption

16. After a Volcanic Eruption