2. Learning Objectives
Explain the difference between a disaster and a catastrophe.
Discuss the role of history in the understanding of natural hazards.
Discuss the components and processes of the geologic cycle.
Apply the scientific method to a natural hazard of your choice.

3. Learning Objectives, cont.
Synthesize the basics of risk assessment.
Explain how much of the damage caused by natural hazards is often related to decisions people make before, during, and after a hazardous event.
Explain why the magnitude of a hazardous event is inversely related to its frequency.

4. Learning Objectives, cont.
Summarize how natural hazards are linked to one another and to the physical environment.
Give reasons why increasing population and poor land-use practices compound the effects of natural hazards and can turn disasters into catastrophes.
Explain how events we view as hazards provide natural service.
Summarize links between climate change and natural hazards.

5. Earthquake in Haiti, 2010: A Human-Caused Catastrophe?
Haiti recognized as an environmental catastrophe waiting to happen
What were once disasters are now catastrophes due to increasing population and poor land-use choices
Haiti’s population increased dramatically in recent decades
About 90 percent of country deforested
Island venerable to hurricanes and other high-intensity storms as well as earthquakes
Four hurricanes and tropical storms hit the island within a month’s time two years before the earthquake

6. Deforestation in Haiti

7. Earthquake in Haiti, 2010: A Human-Caused Catastrophe?
Earthquake became a catastrophe
Eighty-five percent of people in Port-au-Prince lived in slum conditions
Poor conditions lead to 190,000 destroyed or damaged
Killed a quarter million people
Two million homeless with poor sanitation and water quality
Reason for catastrophe was clear: heavy human footprint
Large number of poorly constructed buildings
Population grew so fast

8. Collapsed Buildings in Haiti

9. 1.1 Why Studying Natural Hazards Is Important
Have experienced large, costly, and deadly natural hazards since 1995
Deadliest tsunami caused by earthquake in Indian Ocean
Tsunami in Japan caused by largest and costliest earthquake in recorded history
Catastrophic flooding in different areas of the world
Volcanic eruptions that shut down international airports
Worst tornado outbreak in U.S. history
Etc.

10. Processes: Internal and External
Physical, chemical, and biological ways in which events affect Earth’s surface
Internal processes come from forces within Earth
Plate tectonics
Result of internal energy of Earth
External processes come from forces on Earth’s surface
Atmospheric effects
Energy from the Sun

11. Hazard, Disaster, or Catastrophe
Natural process or event that is a potential threat to human life or property
Disaster
Hazardous event that occurs over a limited time in a defined area
Criteria:
Ten or more people killed
100 or more people affected
State of emergency is declared
International assistance is requested
Catastrophe
Massive disaster that requires significant amount of money or time to recover

12. Major Hazards in the United States

13. Hazard, Disaster, or Catastrophe, cont.
During past half century, there has been a dramatic increase in natural disasters (Figure 1.6a):
Examples: Haitian earthquake, Indonesian tsunami, Hurricane Katrina
United Nation: 1990’s “International Decade for Natural Hazards Reduction”
Mitigation
Reduce the effects of something
Natural disaster preparation

14. Numbers, Effects, and Causes of Worldwide Natural Disasters

15. Death and Damage Caused by Natural Hazards
Effects of hazards can differ and change with time because of changes of patterns of human land use
Natural hazards that cause the greatest loss on human life may not cause the most property damage
Hazards vary greatly in their ability to cause catastrophe

16. Potential for Humans to Influence Selected Natural Hazards in the United States

17. 1.2 Role of History in Understanding Hazards
Natural hazards are repetitive
History of an area gives clues to potential hazards
Maps, historical accounts, climate and weather data
Rock types, faults, folds, soil composition

18. 1.3 The Geologic Cycle
Geologic conditions govern the type, location, and intensity of natural processes
Collectively, processes are called geologic cycle
Subcycles:
Tectonic cycle
Rock cycle
Hydrologic cycle
Biogeochemical cycle

19. The Tectonic Cycle
Refers to large-scale processes that deform Earth’s crust and produce landforms
Driven by forces within Earth
Involves the creation, destruction, and movement of tectonic plates

20. The Rock Cycle Rocks are aggregates of one or more minerals
Recycling of earth materials and linked to all other cycles
Tectonic cycle: heat and energy
Biogeochemical cycle: materials
Hydrologic cycle: water for erosion and weathering
Rocks classified according to how they were formed in the rock cycle

21. The Rock Cycle, cont. Igneous rocks Sedimentary rocks
Form from crystallization of magma
Sedimentary rocks
Rocks are weathered into sediment by wind and water
Deposited sediment undergoes lithification
Metamorphic rocks
Rocks are changed through extreme heat, pressure, or chemically active fluids

22. The Rock Cycle

23. The Hydrologic Cycle
Movement of water between atmosphere and oceans and continents driven by solar energy
Processes include: evaporation, precipitation, surface runoff, and subsurface flow
Water is stored in compartments such as oceans, atmosphere, rivers, stream, etc.
Residence time is estimated average time that a drop of water spends in any compartment
Only a small amount of water is active at any given time

24. Hydrologic Cycle

25. The World’s Water Supply (Selected Examples)

26. Biogeochemical Cycles
Transfer of chemical elements through a series of reservoirs
Related to the three previous cycles
Tectonic cycle: water from volcanic processes; heat and energy required
Rock and hydrological cycles: involved in transfer and storing of chemical elements
Rates of transfer of important chemical elements are only approximate
Carbon, Nitrogen, Phosphorus

27. 1.4 Fundamental Concepts for Understanding Natural Processes as Hazards
Science helps us predict hazards.
Knowing hazard risks can help people make decisions.
Linkages exist between natural hazards.
Humans can turn disastrous events into catastrophes.
Consequences of hazards can be minimized.

28. 1. Science Helps Us Predict Hazards: Science and Natural Hazards
Science is body of knowledge that has resulted from investigations and experiments
Scientific Method
Formulation of a question
Hypothesis is a possible answer to a question and is testable
Data is taken to test the hypothesis
Scientific investigation has improved understanding of natural disasters

29. 1. Science Helps Us Predict Hazards: Hazards Are Natural Processes
They are a result of natural forces
Become hazardous when people live or work near the process and land-use changes amplify their effects
It is possible to control some of these processes to some degree
Most are NOT within our control
Best approach to reduction is to identify the processes and delineate the geographic areas

30. 1. Science Helps Us Predict Hazards: Forecast, Prediction, and Warning of Hazardous Events
Uniformitarianism
“The present is the key to the past”
Human interaction has an effect on geologic processes
“The present is the key to the future”
Environmental Unity
One action causes others in a chain of actions and events

31. 1. Science Helps Us Predict Hazards: Forecast, Prediction, and Warning of Hazardous Events, cont.
Specific date, time, and magnitude of event
Forecast
Range of probability for event
Some hazards can be predicted; most can be forecasted

32. 1. Science Helps Us Predict Hazards: Forecast, Prediction, and Warning of Hazardous Events, cont.
Identify the location of probable event
Most hazardous areas can be mapped
Example: volcanoes and earthquake events are located
Determine probability of event
Estimated based on past events and current conditions

33. 1. Science Helps Us Predict Hazards: Forecast, Prediction, and Warning, cont.
Observe precursor events
Events that precede a hazardous event
Example: earthquakes often precede volcanic eruptions
Forecast or predict event
Forecast gives certainty of event
Prediction will give an estimated time for events
Warning the public
Involves statements to media and public at large

34. Hazard Prediction or Warning

35. 2. Knowing Hazards Risks Can Help People Make Decisions
Risk = (probability of event) x (consequences)
Consequences: damages to people, property, economics, etc.
Acceptable Risk is the amount of risk that an individual or society is willing to take
Frequent problem is a lack of reliable data for either the probability or consequences

36. 3. Linkages Exist Between Natural Hazards
Hazards are linked to each other
Some events may cause others
Example: Hurricanes and flooding
Hazards linked to earth materials
Example: Some rock types are prone to landslides

37. 4. Humans Can Turn Disastrous Events into Catastrophes: Examples of Disasters in Densely Populated Areas
Increases number of people at risk
More loss of life compared to hazardous event in a less dense area
Examples
Mexico City: 10,000 killed in earthquake
Izmit, Turkey: more than 17,000 killed from 1999 earthquakes

38. 4. Humans Can Turn Disastrous Events into Catastrophes: Population Growth as a Factor in Hazards
World’s population has more than tripled in the past 70 years
Population grows exponentially
Increases exposure to hazards, increased pollution, reduced availability of food and clean drinking water, and a greater need for waste disposal and energy resources

39. The Twentieth-Century Rapid Rise in Human Population

40. 4. Humans Can Turn Disastrous Events into Catastrophes: Magnitude and Frequency of Hazardous Events
Impact of hazards depend on
Magnitude: Amount of energy released
Frequency: Interval between occurrences
Other factors: climate, geology, vegetation, population, and land use
Magnitude-frequency concept
Frequency of an event inversely related to magnitude
Land use affects magnitude and frequency of events

41. 5. Consequences of Hazards Can Be Minimized
Primarily reactive in dealing with hazards
Search and rescue
Firefighting
Providing emergency food, water, and shelter
Need to increase efforts to anticipate disasters and their effects
Land-use planning limitations
Hazard-resistant construction
Hazard modification or control
Total losses are direct losses and losses related to human actions

42. 5. Consequences of Hazards Can Be Minimized: Reactive Response
Effects from a disaster can be
Direct (felt by fewer individuals): people killed or dislocated, buildings damaged, etc.
Indirect (affect many more people): emotional distress, donation of money or goods, taxes for recovery, etc.
Recovery from disaster
Emergency work
Restoration of services and communication lines
Reconstruction

43. Recovery from Disaster

44. 5. Consequences of Hazards Can Be Minimized: Anticipatory Response
Options for avoiding and minimizing effects of disasters depends on
Perception of hazards
Attitudes of people to be affected
Awareness
Anticipatory options include
Land-use planning
Insurance
Evacuation
Disaster preparedness
Artificial control

45. 1.5 Many Hazards Provide a Natural Service Function
There are some benefits to hazards
Examples:
Flooding provides nutrients for soil
Landslides form dams to create lakes
Volcanoes create new land

46. 1.6 Global Climate Change and Hazards
Global climate change is likely to change the incidence of some natural hazards
Sea-level rise increases coastal erosion
Deserts and semiarid regions are likely to expand
Warmer ocean water is likely to increase storm activity

47. Chapter 1 Summary Hazards involve repetitive events.
Geological conditions and materials largely govern the type, location, and intensity of natural processes.
Subcycles of the geological cycle are the tectonic cycle, rock cycle, hydrological cycle, and various biogeochemical cycles.

48. Chapter 1 Summary, cont.
Five fundamental concepts establish a philosophical framework for studying natural hazards:
Science helps us predict hazards.
Risk analysis is an important component in our understanding of the effects of hazardous processes.
Linkages exist between different natural hazards as well as between hazards and the physical environment.
Hazardous events that previously produced disasters are now producing catastrophes.
Consequences of hazards can be minimized.

49. Chapter 1 Summary, cont.
Environmental unity states that one action often leads to others in a sequence.
Human population growth and poor land-use decisions are turning former disasters into catastrophes.
The magnitude-frequency concept states that the larger the magnitude of a natural process, the less frequently it occurs.

50. Chapter 1 Summary, cont.
Consequences of a natural hazard event can produce loss of life and property.
Natural service functions refer to benefits provided by a particular process.
Global climate change will likely affect the frequency and intensity of natural hazards.