This document provides an overview of the course content for a class on geological hazards. The course will cover various natural hazards including earthquakes, tsunamis, volcanoes, landslides, storms, wildfires, and floods. It will examine the causes and impacts of these hazards as well as mitigation strategies. Case studies of specific geological hazard events will also be discussed. The course aims to provide an understanding of natural processes and how to assess and reduce risks from natural hazards.

1. Geological
Prof. Javed N. Malik
Department of Earth Sciences
Email: javed@iitk.ac.in
Hazards
Processes
Natural

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Course content
◼ Natural Hazard related impact on environment;
Predicting Catastrophe
◼ Plate Tectonics and related Hazards:
◼ Earthquakes and their causes, mitigation
◼ Active Faults and related hazard in India
◼ Ground Motion and Ground Failures
◼ Tsunami: Gaint Tsunamis
◼ Generation and movement
◼ Tsunami Hazard Assessment & mitigation
◼ Volcanic Eruption and Hazard:
◼ Eruption-Type of Volcanoes and Tectonic environment
◼ Landslides:
◼ Cause, classification, zonation and protection; Land subsidence

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Course content
◼ Storms: Tropical Cyclone
◼ Hurricane, Tornado, Storm damage and safety
◼ Wildfires:
◼ Fire Process and Secondary effects
◼ Floods:
◼ Streams and rivers-hydrology; types of floods, nature and
extent of flood hazard, flood hazard zoning - flood control and
protection
◼ Case studies: Geological hazards

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Text Books:
◼ Bell, F. G. Environmental Geology
◼ Keller, E.A. Environmental Geology
◼ Horn & Scott, Geological Hazards
◼ Monroe, J. S., Wicander, R., and Hazlett, R. Physical
Geology: Exploring the Earth.
◼ Strahler, A. Introduction to Physical Geology.
◼ Hyndman, D., and Hyndman, D. Natural Hazards and
Disasters.
◼ Keller, E. D. Introduction to Environmental Geology

5. ◼ Natural hazards – a growing threat (Stewart and
Donovan, 2007)
“In a time of extraordinary human effort to live
harmoniously in the natural world, the global death toll
from extreme events of nature is increasing. Loss in
property from natural hazards is rising in most regions of
the earth, and loss of life is continuing or increasing
among many of the poor nations of this world”
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NATURAL HAZARDS:
◼ Natural Hazards are the naturally occurring processes which are
dangerous to human life and property
◼ Earth surface is susceptible to a variety of natural/geological
hazards
◼ These events can happen anywhere
❑ Atmospheric hazards
➢ Climate Change
➢ Fog
➢ Tropical Cyclone/
Hurricane/Storms
➢ Snow and ice
➢ Tornado
➢ Thunderstorm
➢ Wild land fire
❑ Geologic hazards
➢ Earthquakes
➢ Slope failures
➢ Floods
➢ Droughts
➢ Volcano
➢ Tsunamis

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The term natural hazard implies the occurrence of a natural condition or
phenomenon, which threatens or acts hazardously in a defined space and time
Hazards
Endogenic process
• Volcanism
• Earthquakes
Exogenic process
• Floods
• Karst Collapse
• Snow Avalanche
• Mass Movement
• Tsunami
• Coastal Erosion
Climate and
Land Use change
• Desertification
• Permafrost
• Degradation
• Floods
• Salinity
Natural Hazards

9. ◼ Plate movements
◼ Geothermal energy
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Earth system

10. External processes
◼ Hydrological cycle

11. The System Concept

12. The System Concept
• A system in any portion of the
universe that can be isolated
from the rest of the universe
for observing and measuring
change.
• The simplest kind to understand
is an isolated system.
• The boundary completely
prevents the exchange of either
matter or energy.

13. The System Concept (2)
• The nearest thing to an
isolated system in the real
world is a closed system:
• i.e., such system has a
boundary that permits the
exchange of energy with
its surroundings, but not
the matter.

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1. Electromagnetic Radiation
The wavelength (λ) is given in μm (10-6 m) or nm (10-9 m).

15. • Incoming radiation from the sun: Shortwave radiation
(Visible and UV radiation)
• Outgoing radiation from the Earth: Long wave radiation

17. The Earth System (1)
• Earth is only approximately a
closed system because:
• Because meteorites coming
from space and fall on Earth,
causes slight escape of gases
into space
• Moreover, Earth is comprised
of four open systems.

18. The Earth System (1)
• The Earth system is composed of:
• The geosphere (rocks)
• The atmosphere (air)
• The hydrosphere (water)
• The biosphere (life in all its forms)
• Energy and materials (like water,
carbon, and minerals) are
transferred from one system to
another.
• To a close approximation, Earth is
a closed system.

19. An open system can exchange
both energy and matter across
its boundary.
open system

20. An open system can exchange
both energy (sunlight) and
matter across its boundary,
e.g., Drainage Basins are
internal Open Systems

21. Open system
• The geosphere (rocks)
• The atmosphere (air)
• The hydrosphere (water)
• The biosphere (life in all
its forms)

27. Earth’s environmental systems
◼ The Earth’s environment has a complex
networks of systems interlinked with one
another...

28. Human Influences
◼ We human are influencing Earth’s
external geologic processes.
◼ More than 7 billion people.

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30. Human Influences (2)
❑ Our daily activities are having measurable
effects on:
❑ Rainfall
❑ Climate
❑ Air
❑ Water quality
❑ Erosion

31. • To have proper understanding of the
earth processes it is essential to know
various natural process related to the
Earth and its Environment:
• Internal processes
• External processes

32. Cyclone Vardah

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• A tropical cyclone is an intense low
pressure area in the atmosphere
over tropical or sub-tropical waters.
• The direction of circulation is
anti-clockwise in Northern
Hemisphere and clockwise in
Southern Hemisphere due to
Coriolis effect...
• IMD - India Meteorological
Department classifies the low
pressure systems in the Bay of
Bengal and in the Arabian Sea into
7 classes
Type of
Disturbances
Wind Speed in
Km/h
Wind Speed in
Knots
Low Pressure Less than 31 Less than 17
Depression 31-49 17-27
Deep Depression 49-61 27-33
Cyclonic Storm 61-88 33-47
Severe Cyclonic
Storm
88-117 47-63
Super Cyclone More than 221 More than 120
Cyclones

34. Cyclone Vardah
• Developed over SE Bay of Bengal
(BOB), in the afternoon 6th Dec. 2016
• Moved westward
• Crossed Tamil Nadu coast near
Chennai on 12th December 2016.
• After the landfall, it moved SW and
weakened
• 18 killed in Tamil Nadu

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47. Cyclone Vardah
Peak Intensity
130 km/h

48. The Kaikoura, New Zealand earthquake occurred
on 14 Nov. 2016
(Magnitude 7.8); depth of 22 km; 70 km ruputre (36km on
land and 34km under the sea)

49. Background

50. A M 7.8 earthquake occurred
on 13 November 2016

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Paptea Fault

53. Kekerengu Fault
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Geological hazards
➢ Earthquakes
➢ Tsunamis
➢ Cyclones/storms
➢ Slope failures
(Landslides)
➢ Floods

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General Background of Natural
Hazards
◼ Many developing countries of the Asia and
Pacific are situated in the world’s hazard
belts and are subjected to floods, cyclones,
earthquakes, windstorms, tidal
waves/tsunamis, landslides, etc.
◼ The major natural disasters that occur
periodically in this region are largely due to
climatic and seismic factors. The region has
suffered 50% of the world’s major natural
disasters
◼ Vulnerability to disasters has increased due
to the increased aggregation of people in
urban centers, environmental degradation,
and a lack of planning and preparedness.
◼ Vulnerability to natural hazards has
increased in many coastal areas due to the
loss of coastal habitats such as mangroves
and coral reefs that provide natural
protection from marine flooding and even
tsunamis.

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Why Natural Processes are hazardous ??
If there is change in Landuse pattern
Urbanization Deforestation
Landslides in Hilly
terrain and flooding
in plains
Increase in
Population
Growth
Utilization
of
Agricultural
fields
Disturbing climate due
to pollution and
eco-system human
activity

57. Human Impact of Natural Disasters
◼ A natural process when poses a threat to human life or property,
- it is termed as a natural hazard.
◼ Whereas, a natural event that kills or injures large numbers of
people or causes extensive damage to the property, it is called a
catastrophe
◼ Many geologic processes are potentially hazardous, e.g., floods,
earthquakes, tsunamis, cyclones etc.
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12 Jan 2010
Haiti earthquake
Mw7.0

58. Human Impact of Natural Disasters
◼ We need to understand the impact of the natural disaster – which does not depend on the size
of the event but on number of people getting affected and the area vulnerable to such events.
◼ e.g., An event in a thinly populated area can hardly pose a major hazard.
◼ For instant, earthquake in New Zealand on July 15, 2009 with M7.6 was severe but posed little
threat because it happened in a region with few people or buildings.
◼ Whereas, October 8, 2005 Muzzaffarabad earthquake with M7.6 occurred in heavily populated
valleys of the southern Himalayas killed more than 80,000 people, and a much smaller January
12, 2010, M7.0 earthquake in Haiti killed more than 222,000.
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59. Natural Disasters Impact on Human
◼ Similarly, May 2, 2008, cyclone in
Myanmar killed about 138,000 in a
mostly rural area.
◼ Whereas, the Super typhoon Choi-
Wan, of category 5 storm that passed
directly over the Northern Marianas
Islands south of Japan on September
15, 2009, resulted in no deaths
because few people live there.
◼ The eruption of Mount St. Helens in
1980 caused few fatalities and
remarkably little property damage
simply because the area surrounding
the mountain is sparsely populated.
◼ On the other hand, a similar eruption
of Vesuvius, on the outskirts of
Naples, Italy, could kill hundreds of
thousands of people and cause huge
property damage.
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Flooding during Hurricane Ike in 2008 on the barrier island
east of Galveston, Texas, toppling them into the surf.

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◼ The study of natural hazards is a part of Environmental Geology
◼ Because natural hazards are Catastrophic events, which have
direct impact of human lives and cause deaths and damage.
◼ If such event occur, then it takes long time for recovery and
rehabilitation.
◼ One can study the processes and identify the potentiality of the
particular hazard in particular area.
◼ Make information available to the users – to avoid or to reduce
the risk
Why one needs to understand the natural hazards?
How to study? What one should do?

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62. Natural Disasters in India
◼ India is vulnerable to a large number
of disasters.
◼ More than 58.6 per cent of the
landmass is prone to earthquakes of
moderate to very high intensity
◼ Over 40 million hectares (12%) of its
land is prone to floods and river
erosion
◼ About 5,700 km, out of the 7,516 km
long coastline is prone to cyclones and
tsunamis
◼ About 68% of its cultivable area is
vulnerable to droughts
◼ Its hilly areas are at risk from
landslides and avalanches.
◼ Moreover, India is also vulnerable to
Chemical, Biological, Radiological and
Nuclear (CBRN) emergencies and
other man-made disasters.
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Source NDMA, New Delhi