Terminology and basic concepts for a GE-level course in natural disasters.

1. Introduction to Natural Disasters

2. Hazard
A condition that threatens human life or property
Photo by W. W.
Little

3. Disaster
An event that results in loss of
property or life that exceeds the
capacity of the community to
respond.

4. Catastrophe
A large-scale disaster that results in massive loss of life and property
that has long-term societal (economic, political) impacts.

5. Natural
A process, condition, event, or item not controlled or influenced by
human activity.

6. Common Natural Disasters
Earthquakes Volcanoes Tsunamis Landslides
Hurricanes Tornadoes Blizzards Dust Storms
Floods Droughts Wildfires Sink Holes

7. Linked Events
Rock avalanche caused by
earthquake (Yungay, Peru).
Lahar caused by volcanic
eruption (Mt. St. Helens).
One type of event can trigger a different type of event.

8. Magnitude (Energy)
Richter Scale for earthquakes Volcanic Explosivity Index
Enhanced Saffir-Simpson Scale for hurricanes Fujita Scale for tornadoes
Refers to the size of an event as measured by a defined scale.

9. Frequency (Recurrence Interval)
Refers to how often a type and size of event is repeated. Varies
greatly by nature of event and by local conditions; therefore,
determined on a local and regional basis using broad averages.

10. Magnitude vs. Frequency
There is an inversely proportional relationship between disaster
magnitude (released energy) and frequency.

11. Is the Number of Natural
Hazards/Disasters/Catastrophies
Increasing?
“The many eruptions, earthquakes and tidal waves which have
occurred...are signs which the Savior declared would foreshadow
his second coming... The wise and prudent will heed the warning
and prepare themselves that they be not taken unawares.”
Joseph F. Smith (Messages of the First Presidency, 4:132)

12. News Scientist, 16 January 2012
Depends on Time Frame

13. Population Impact
Global Population Change
Global Population Distribution
Global Flood Hazard Map

14. Population Impact: Nevado del Ruiz
• 1845: Volcanic eruption triggers a lahar killing ~1,000 people.
• 1845 – 1985: Population increases due to fertile volcanic farm land.
• 1985: Volcanic eruption triggers a lahar killing ~21,000 people.

15. Urbanization Impact
Manmade features can both exacerbate and mitigate the impact
of natural hazards.

16. Mitigation
Efforts to reduce consequences of natural processes or events.

17. Prior History
Most natural processes have a somewhat regular recurrence
interval, allowing a very general predictability based mostly on
a statistical probability of occurrence over a broad span of time.

18. Recognition of Precursors
Conditions or occurrences that precede a disaster, providing
warning that an event is likely. Not all events have precursors.

19. Warning Systems
Sirens for flash floods, tornadoes,
and mass wasting.
Buoys for tsunamis.
First-motion dectectors for earthquakes.
News media for hurricanes, blizzards,
and regional flooding.

20. Risk Analysis (Hazard) Maps
Based on past history of a locality and comparison with similar
localities, maps can be produced that show the potential risk for
specific types and magnitudes of geological and hydrological events.

21. Generalized Hazard Maps for the U.S.
Earthquakes Volcanism Mass Wasting
Hurricane
s
Floods

22. Engineering Advances
Kashmir, Pakistan 2005, Mw 7.6
Vina del Mar, Chili 2010, Mw 8.8

23. Retrofitting Structures
Some historical structures are retrofitted to mitigate earthquake
damage while maintaining original character.

24. Federal Relief Spending
What is the role of the federal, state, and local governments, of
insurance companies, and of personal responsibility?

25. Best Advice: Be Prepared
The prudent see danger and take refuge, but the
simple keep going and suffer for it.
Proverbs 27:12
“Too often we bask in our comfortable complacency and rationalize that the ravages of war, economic
disaster, famine, and earthquake cannot happen here. Those who believe this are either not acquainted
with the revelations of the Lord, or they do not believe them. Those who smugly think these calamities
will not happen, that they somehow will be set aside because of the righteousness of the Saints, are
deceived and will rue the day they harbored such a delusion.”
Ezra Taft Benson, “Prepare for the Days of Tribulation,”
Ensign, Nov 1980, 32
‘’In mercy the Lord warns and forewarns. He sees the coming storm, knows the forces operating to produce
it, and calls aloud through His prophets, advises, counsels, exhorts, even commands— that we prepare for
what is about to befall and take shelter while yet there is time. But we go our several ways, feasting and
making merry, consoling conscience with the easy fancy of ‘time enough’ and in idle hope that the tempest
will pass us by, or that, when it begins to gather thick and black about us we can turn back and find
shelter.’’
James E Talmage, The Parables of James E. Talmage, p. 50

26. Mitigation Impact
Though the number of people affected and the cost of natural
disasters has increased in recent decades, the number of
deaths have decreased.

27. Most Costly Events: 1980-2011

28. Most Deadly Events: 1980-2011

29. All-time Most Deadly Events