What do we learn in Natural Hazards Course?

Presenter: Dr. Yuri Gorokhovich, Lehman College

1. Concept of multi-hazard approach

2. Geographic Information Systems techniques

3. Making maps and working with digital data

As population continues to grow, hazards, disasters, and catastrophes

become more common.

Why Studying Natural Hazards Is Important?

Definitions of hazards, disasters and

catastrophes:

A natural hazard is any natural process

that poses a threat to human life or

property. Examples.

A disaster occurs when a hazard, such as

a flood or earthquake, inflicts loss of life

and property in over a limited time span in

a defined area. Examples.

A catastrophe is a massive disaster,

typically with many deaths, requiring a

large input of time and money to rectify.

Examples.

Acts of God

Acts of Man

1. Precursors: earthquakes, volcanic eruptions and other natural and

anthropogenic (wars, deforestation, etc.) influences

2. Early warning

3. Preparedness:

• Directed operations, command, control

• Education, scientific research and monitoring, building local capacity

4. Response:

• Management and Planning

• Building resilience, decrease vulnerability

5. Post-disaster recovery

6. Post-disaster analysis and conclusions:

• Mitigation and prevention

Disaster stages and lessons:

Illustrated version:

http://www.youtube.com/watch?v=ya0sO5pxeZk

Global Distribution of Natural Hazards (1993-2002)

Source: WMO,

http://www.uncosa.unvienna.org/docs/iamos/2005/open_session_presentations/WMO_files/frame.htm#slide0138.htm

Role of Internal and External (blue) processes

The rock cycle may be considered a worldwide earth-material recycling

process driven by Earth’s internal heat,

Driven by solar energy, the hydrologic cycle operates by way of evaporation,

precipitation, surface runoff, and subsurface flow.

Biogeochemical cycles can be described as the transfer of chemical elements

through a series of storage compartments or reservoirs, such as air or

vegetation.

Geologic factors of Natural Processes

The Tectonic Cycle

Hazards: Volcanoes, Earthquakes; Long - term: Climate change

Involves the creation, movement, and destruction of tectonic plates through geologic

process driven by forces deep within Earth.

The Hydrologic Cycle

Hazards: Climate change, Hurricanes, Tornadoes, Floods, Droughts, Wildfires

Solar energy

drives

movement of

water

between

atmosphere

and oceans

and

continents.

Biogeochemical Cycles

The major natural biochemical

cycles include the carbon,

nitrogen, and phosphate

cycles

Plants such as trees and

algae undergo the

photosynthesis reaction where

carbon dioxide and water in

the presence of sunlight are

converted to organic materials

and oxygen.

Fish use metabolism where

oxygen and organic materials

- other small fish or algae - as

food is converted to carbon

dioxide, water, and energy.

Bacteria in water, as well as land, also undergo metabolism and use oxygen and decompose organic

wastes as food to convert to carbon dioxide, water, and energy. By products in the decomposition of

organic waste are nitrates and phosphates.

Hazards: Climate change, ecological disbalance

Death and Damage Caused by Natural Hazards

Role of History in Understanding Hazards

1. A better understanding and more accurate prediction of natural processes come by

integrating historic and prehistoric information, present conditions, and recent past

events, including land-use changes.

2. Historical events provide the basis for preparedness

3. Current information collected by monitoring provides the basis for early warning

4. Historical analysis of majority of types of disasters shows that magnitude of a

hazardous event is inversely related to its frequency

Role of History in Understanding Hazards: Santorini

Volcanic Complex in Greece

Population: 13,600 people

Tourism adds 1,000,000 per year

Housing flourishes

Role of History in Understanding Hazards: Santorini Volcanic Complex

Periodicity of destructive events similar to Minoan eruption: 20,000 years

Minoan eruption (1640 BCE): no victims

Now: No emergency plan, no

coordination between emergency

response units. Training? Preparedness?

Possible eruption: similar to any post-

Minoan eruption

Possible outcome: ???? Why???

Climate Change Hazard:

Was Earth an “ice” or “hot house”?

Learning from historical data

http://www.scotese.com/climate.htm

Five fundamental concepts establish a philosophical

framework for studying natural hazards.

1. Hazards are predictable from scientific evaluation. However, this does not

include the prediction of exact time and geographic location.

2. Risk analysis is an important component in our understanding of the effects of

hazardous processes.

3. Linkages exist between various natural hazards as well as between hazards

and the physical environment. Multi-hazard concept.

4. Hazardous events that previously produced disasters are now producing

catastrophes.

5. Consequences of hazards can be minimized

Comparison of natural disaster fatalities in the United States. Cumulative size-frequency

distributions for annual earthquake, flood, hurricane, and tornado fatalities. In addition to

demonstrating linear behavior over 2 to 3 orders of magnitude in loss, these data group into

two families. Earthquakes and tornadoes are associated with relatively flat slopes (D=0.4 -

0.6); while floods and tornadoes have steeper slopes (D=1.3 - 1.4).

Magnitude and Frequency of Hazardous Events

Source: Barton and Nishenko. Natural Disasters—Forecasting Economic and Life Losses. USGS Facts

Sheet. http://pubs.usgs.gov/fs/natural-disasters/index.html

Fatalities per event

Cum

ula

tive n

um

ber

of

events

per

year

Human Population Growth and its relation to Natural Hazards

Population growth has negative and

positive effects:

- Land use change; depletion of

resources; social disparity

- Intellectual development (do we use it

wisely ?)

5. Consequences of Hazards Can Be Minimized

• Move from reactive response: Recovery and restoration

• To an anticipatory response: Avoiding and adjusting to hazards:

– Land-use planning

– Building codes

– Insurance

– Evacuation

– Disaster preparedness

– Artificial control

Benefits of Hazards

• Natural hazards have nature’s service function

• Examples:

– Flooding provides nutrients for soil.

– Landslides form dams to create lakes and habitat.

– Volcanoes create new land and enrich soil.

– Volcanoes contribute gases to the atmosphere and

produced first water on the planet.

– Hurricanes destroy old forest, enrich soil, replenish

aquifers

– Erosional processes (flooding, river erosion, etc.) help

enrich soil, provide mineral resources and sustains life