This document provides an overview of volcanism and volcanic processes. It discusses the types of volcanoes such as shield volcanoes, composite volcanoes, cinder cones and lava domes. It also describes volcanic deposits including lava, tephra and lava tubes. Additionally, it covers the distribution of volcanoes along plate boundaries and volcanic belts. The document outlines methods for predicting volcanic eruptions in both the long-term by examining geological records, and short-term by monitoring changes in gas emissions, earthquakes and ground deformation near active volcanoes. Finally, it discusses volcanic hazards such as lava flows, pyroclastic flows, lahars and toxic gases.

2. NED University of Engineering & Technology
Department Of Urban & Infrastructure Engineering

4.  Volcanism
 Types Of Volcanoes
 Types Of Deposits
 Formation and Behaviour
 Distribution Of Volcanoes
 Prediction Of Volcanic Eruptions
 Volcanic Hazards
 Valcano Advantages
 Conclusion
Contents

5. Volcanism
Volcanism is the phenomenon of eruption of molten
rock (magma) onto the surface of the Earth

6. Volcanic Process

7. Aspects Of Volcanism
1. Earthquake
2. Volcano
1.Earthquake
An earthquake (also known as a quake, tremor or
temblor) is the result of a sudden release of energy
in the earth's crust that creates seismic waves. The
seismicity, seismism or seismic activity of an area
refers to the frequency, type and size of
earthquakes experienced over a period of time .

8. Naturally occurring earthquakes
Earthquake fault type
Size and frequency of occurrence

9. Effects Of Earthquakes
 Shaking and ground rupture
 Landslides
 Soil liquefaction
 Tsunami
 Floods

10. State Of Volcanoes
• Volcanoes can be active, dormant or extinct.
• Volcano is active or alive if at the present time it is
expected to erupt
• Volcano is dormant or sleeping that is not erupting or
predicted to erupt in the near future
• A volcano is extinct or dead that no one expects will
ever have another eruption
http://www.basicplanet.com/classification-volcanoes/

11. Active Volcano
• the best examples of this classification of volcanoes
would be Kilauea which has been erupting since 1983.
http://www.basicplanet.com/classification-volcanoes/
Kīlauea is a currently
hyperactive shield volcano in
the Hawaiian Islands, and the
most active of the five
volcanoes that together form
the island of Hawaiʻi

12. Dormant Volcano
• Mauna Kea is a volcano which is located on Big Island
and its last eruption took place 3,500-4,000 years
ago. However scientists believe that it will erupt again
Mauna Kea is a
dormant volcano on
the island of Hawaii.
Standing 4,205 m
above sea level

13. Extinct Volcano
• One such volcano is also located on Hawaii’s Big Island
and its name is Kohala. The last time that Kohala
erupted was close to 60,000 years ago. As of now
scientists do not believe that volcano will ever be
active again
Kohala is the oldest of five
volcanoes that make up the
island of Hawaii. Kohala is an
estimated million years old

14. Types Of Volcanoes
• Classification of volcanoes is done on the basis of
shapes, magnitude, structure and materials of
different volcanoes also the way these volcanoes
erupt.
• There are four different types volcanoes:
1. shield volcanoes
2. composite volcanoes
3. cinder cones
4. lava domes
http://www.livescience.com/27295-volcanoes.html

15. Shield Volcanoes
• Shield volcanoes are very very big in size
• Shield volcanoes are shaped like a bowl with long
gentle slopes made by the lava flows.
• If the magma is runny, the gas can escape easily and
there will not be an explosion. The magma just comes
out of the mountain and flows down the sides that is
why they are not so much dangerous.

16. Muana Loa Volcano – the world’s largest
volcano
Mauna Loa is about 55,770 feet from its base,
which is 13,681 feet above sea level. It is also one
of the Earth’s most active volcanoes and is
carefully monitored. The most recent eruption was
in 1984.
• Fluid Flow, high
temperature, low silica
• shield volcanoes is less
viscous, so it flows much
more easily. For this
reason, the eruptions of
shield volcanoes are non-
explosive
• They are flat mount

17. Composite Volcanoes
• Composite Volcanoes (lava and pyroclastic deposits).
• They are known as ‘Strato Volcanoes’.
• If the magma is thick and sticky (like honey), the gas
cannot escape, so it builds up and up until it explodes
sending out huge clouds of burning rock and gas.
• composite volcanoes eruption is dangerous and explosive
in nature. With a lot of layers of lava and pyroclastic
materials involved.

18. • Stratovolcanoes erupt with great violence.
• Composite volcanoes are big, they can range from 1 –
10 km in diameter
Stratovolcanoes are considered the
most violent eruptions. Mount St.
Helens, in Washington state, erupted
on May 18, 1980. Approximately 230
square miles of forest was completely
Destroyed and 57 people were killed.
Ash was blown up into the atmosphere
and fell over 11 states.

19. Cinder cones Volcanoes
• Cinder cones are the most common type of volcano
and also the smallest
• Cinder cones are circular or oval cones built from
erupting lava that breaks into small pieces As small
pieces fall back to the ground, they cool and form
cinders around the vent.
http://ete.cet.edu/gcc/?/volcanoes_types/

20. Paricutin in Mexico
• Parícutin is a cinder cone volcano in the
Mexican state of Michoacán
• The volcano is unique in the fact that
its evolution from creation to
extinction was witnessed
• Last Eruption: 1952
single opening. The opening of
a cinder cone is a cone-shaped
structure, while the steeps
are formed of the erupted,
fragmented cinders that fall
close to the chimney/vent.

21. Lava Domes
Volcanoes
• Lava domes are formed when erupting lava is too
thick to flow and makes a steep-sided mound as the
lava piles up near the volcanic vent.

22. Kelud Volcano-Indonesia
Kelud is a volcano located in
East Java on Java in Indonesia.
Like many Indonesian volcanoes
and others on the Pacific Ring
of Fire, Kelud is known for
large explosive eruptions
throughout its history
• lava domes are formed when the lava is too
viscous to flow to a distance so it
continues to pile within. As the lava dome
keeps growing, the outer surface starts to
cool and become hardened. When a lava
dome is grown to a significant extent, it
shatters the outer surface, which results
in spilling loose fragments.

23. Volcanic Deposits
 Result of materials like rock and gases emitted from
a volcanic eruption.
 Result of magma to break through to the surface.
Types Of Deposits
1. Lava:
 Hot (up to 1200 degrees C) ,
fluid, molten rock that
flows along the land surface.

24. 2.Pahoehoe
Basaltic lava that has a
smooth, hummocky, or ropy
surface
2.1: Ropy Pahoehoe
ropy pahoehoe form when
the thin, partially solidified
crust of a flow is slowed or
halted
2.2:Coil Pahoehoe
Lava coils are spiral or
scroll-shaped features that
are formed along slow-moving
shear zones in a flow.

25. 2.3:Aa
 Blocky, rough lava solid flow. Due to high viscosity
lava that flowed pushing chunks of and semi-solid
blocks.

26. 3:Lava tube:
 A tube formed by cooling
and solidifying of the lava
walls while fluid lava
continued to flow inside.
3.1:Pillows:
 A form of closed lava tube
(with a bulbous end) that
when a lava flows into
water (e.g., a lake or
ocean) and cools very
rapidly

27. 4:Tephra
 The general term for all pyroclastic material.
 Different terms apply according to the size of the
tephra.
4.1.1: Lapilli:
from 2 mm to 64 mm
in diameter
4.1.2:Ash
tephra that is finer than 2 mm in diameter
4.1:Types of tephra

28. 1.Magma Formation
Magma is a mixture of molten or semi-molten rock,
volatiles and solids that is found beneath the surface of
the Earth, and is expected to exist on other planets.
2.Magma Viscosity
 Composition
 Temperature
 Silicon Content
 H2O Content

29. 3- Gases Evolved During Eruption
1- Water Vapour
2- Carbon dioxide
3- Sulphur Dioxide
4- Hydrogen Fluoride
5- Hydrogen Chloride

30. Sites where magma is erupted
Places where magma is erupted are known as Vent or Crater.
In Pakistan recents volcanic erruption took place in

31. Distribution Of Volcanoes

32. 1: Plate Boundries

33. 2: Volcanic Belts
2.1: Circum Pacific Belt
 Ring of fire
 South America ,Central
America , Maxico,
Mountains of United
States , Japan ,
Philipines , New zealand

34. 2.2: Mid-Continental Belt
 Mediterranean sea ,
Hindu kush
 Emit steam and other
gases
 Extinct volcanoes

35. 2.3: MidAtlantic Belt

36. Prediction Of Volcanic
Eruptions
1:Long Term Prediction
• Identify volcanoes and the frequency and style of
their eruptions.
• Establish probabilities of eruption, style and location
for individual volcanoes.
• Establish the level of risk based on historic and
geologic record.
• E.g., for individual volcanoes: determine most likely
routes for lahars, lava flows, etc., and avoid
construction in those areas.

37. Hazard zones have been distinguished around Mt.
Shasta based on topography and past experience with
eruptions.
 Zone 1: areas likely to be
affected most frequently.
Most future flows from
summit eruptions probably
would stay within this zone.

38.  Zone 2: areas likely to be
affected by lava flows
erupted from vents on the
flank of the volcano or that
move into zone 2 from zone 1.
Zone 3: areas likely to
be affected infrequently
and then only by long lava
flows that originate at
vents in zones 1 and 2
.

39. 2: Short-term Prediction
 Based on the recognition of a pattern of events prior
to previous eruptions.
 Gas emissions: rates of emission and type of gas
changes in some volcanoes.
 Important gases include sulfur dioxide (SO2) and
carbon dioxide (CO2)
 Changes in concentration may reflect movement of
the magma up the vent.

40.  Earthquakes: generated as the magma moves up the
feeder conduit to the vent.
 When viscous magma becomes stuck in the conduit
strain energy builds as more magma tries to push out.
 Movement takes place in a series of “jerks” as the
rock material breaks. Each “jerk” produces an
earthquake.
 Magnitudes generally less than 5 m.
 The more earthquakes the further the magma has
moved.

41.  The more earthquakes the further the magma
has moved.

42. Volcanic Hazards
 Volanoes give rise to numerous geologic and
hydrologic hazards.
 The most volcanically active regions of the
nation are in Alaska , Hawaii ,california,
oregon, and washington .
 Large explosive eruptions can endanger
people and property hundreds of miles away
and even affect global climate .

43. Volcanic gases
 volcanic emit gases during
eruptions.
 Even when a valcano is not
erupting cracks in the ground allow
gases to reach the surface through
small opening fumaroles .
 Carbon dioxide is heavier than air
and can be trapped in low areas in
concentrations are deadly to people
and animals .

44. Earthquake Due To Volcano
 It occur due volcanic activity.
 Produced by stress change in
solid rock due to withdrawal of
magma
 When magma suddenly forced
into surrounding rocks .

45. Eruption columns and clouds
 Explosive eruption blast solid and
molten rocks fragments .
 The largest rocks fragments
usually fall back to ground within
two miles of vent
 Small fragments of volcanic glass,
minerals and rock rise high into the
air

46. Pyroclastic flows
 High speed avalanches of hotash
, rock fragments and gases can
move down the slide of volcano
 These flows can be hot and
move at speed 100 to 150 miles
per hour
 Such flows tend to follow valley
and capable of knocking down
and burning every thing in their
path .

47. Advantages Of Volcanism
Geothermal Energy
 Geothermal energy means heat energy from the
earth.
 The heat from underground steam is used to drive
turbines and produce electricity, or to heat water
supplies that are then used to provide household
heating and hot water.
 Where steam doesn't naturally occur it is possible to
drill several deep holes into very hot rocks, pump cool
water down one hole and extract steam from another
hole

48.  Countries such as Iceland make extensive use of
geothermal power, with approximately two thirds of
Iceland's electricity coming from steam powered
turbines.
 Iceland has over 200 volcanoes and 800 hot springs

49. Minerals
 Magna rising from deep inside the earth contains a
range of minerals.
 This means that minerals such as tin, silver, gold,
copper and even diamonds can be found in volcanic
rocks.
 Hot gasses escaping through
 Vents of active volcanoes also
 Bring minerals to the surface,
 Notably sulphur, which collects
 Around the vents as it
 Condenses and solidifies.

50. Volcanic rocks are often used in construction.
As early as 300 bce, romans made concrete
from volcanic ash and lime.
This material was used to build the colosseum
in rome in 80 ce. The strength of this
material has allowed the colosseum to stand
for nearly two thousand years

51.  Geothermal water can
be used to drive turbines
that generate electricity.
 It can also be used to
heat homes, grow crops,
or keep roads free of ice.

52. Fertile Soils
 Volcanic rocks are rich in minerals, but when the
rocks are fresh the minerals are not available to
plants.
 The rocks need thousands of years to become
weathered and broken down before they form rich
soils.
 When they do become soils though, they form some
of the richest ones on the planet.
 The Naples area, which includes Mount Vesuvius, has
such rich soils thanks to two large eruptions 35,000
and 12000 years ago. Both eruptions produced very
thick deposits of ash and broken rocks which have
weathered to rich soils

53.  Pumice is added to soil to allow air and water to
circulate more easily through the soil.
 Because metals in pumice are not water soluble,
pumice is used alone or with silica sand to filter
drinking water.
 As recently as the 20th century, volcanic ash was used
to make concrete for dams in the United States.
 Today, basalt and pumice are often used in the
construction of roads and bridges, and the production
of concrete.

54. References
 www.bbc.co.uk
 www.preservearticles.com
 www.geologywestcountry.blogspot.com
 www.USGS.com
 http://www.basicplanet.com/classification-volcanoes/
 http://www.livescience.com/27295-volcanoes.html
 http://ete.cet.edu/gcc/?/volcanoes_types/
 en.wikipedia.org/wiki/Earthquake