Japan, 2011 (LA Times)

Learning Objectives In this first chapter, we will learn the basic terminology and approach to natural disasters. Your goals in studying this chapter are to:

• Understand the definitions of disaster, risk, mitigation, and related terms.

• Understand the statistical trends of disasters over time.

• Understand the economic effects of disasters.

Pompeii, Italy (BYUI)

Basics, Definitions, and Statistics

What is a Disaster?

The legal definition of “disaster” is a natural or man-made emergency whose response needs exceed the available resources of the affected

community. Disasters are not just emergencies that make the news! Large-scale disasters are sometimes also called catastrophes.

There were 4,215 traffic-related fatalities in California in 2003, yet this was not called a “disaster” because it did not exceed the affected

communities’ abilities to respond. The deaths are certainly personal tragedies, but they do not meet the requirements of “disaster.”

For comparison, all of the deaths associated with the September 11, 2001 attacks totaled 2,992. In addition, the attacks caused billions of

direct and indirect economic losses. That qualifies this human-caused event as a disaster.

A single homicide is a crime and a tragedy, and an attack on innocent people with political intent is terrorism. But both may not be a disaster.

On the other hand, the San Simeon, California earthquake of December 2003 that resulted in only 2 fatalities, but caused hundreds of millions

in property losses, was a disaster.

As stated above, disaster professionals define a disaster as a natural or man-made emergency whose response needs exceed available resources.

That makes the definition scalable, depending on the size of the affected community. When local government resources are exceeded, the state

Governor’s Office of Emergency Services (State OES) is contacted and the Governor is requested to declare a State Disaster. When State

resources are exceeded, State OES contacts the U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) and

the President is requested to declare a National Disaster. This Presidential Declaration triggers funding resources for the public, the state, and

local governments to use for clean-up, repair, recovery, and mitigation. In another example, the Haiti earthquake of 2010 obviously overwhelmed

that nation’s ability to respond, and so was an international disaster. At a smaller scale, the 2005 landslide at the LaConchita neighborhood in

southern California overwhelmed the neighborhood’s capacity to respond, and so was a local disaster, but was not a state disaster. We must,

therefore, always take the scale of an event into account when we discuss it as a “disaster.”

A hazardous natural condition is called a natural hazard. Types of hazards include earthquakes, volcanic eruptions, and the other things we will

study this semester. They do not become disasters until they affect people.

Exposure

If a river overflows its bank in an uninhabited area with no roads and no buildings, it is a

flood, but not a flood disaster. If a major earthquake occurs in the desert where no one lives,

it is still an earthquake, but not an earthquake disaster. In dealing with hazards, then, we are

concerned about the location of people, buildings, and infrastructure relative to hazards.

The number of these things in harm’s way is our hazard exposure.

Probability

Probability is the likelihood of a specific type of event occurring in a specific place, at a

specific magnitude, and during a specific time frame. Because the natural events that cause disasters are not common, calculating their

probabilities can be complex. Probability is only one component of “risk.”

Risk and Mitigation

Risk is calculated as the product of extent, effects, probability, and importance of the outcome. Notice that if any of these factors is zero, risk

is zero. If any factor has a high value, risk is increased. For example, for a tornado in an uninhabited place the effects and importance are zero,

meaning this tornado poses no risk. On the other hand, the tornado that destroyed the town in the above photo obviously caused serious

effects and its outcome was quite important; therefore, tornado risk for this type of tornado in this location was high.

Mitigation is activities to reduce losses from future disasters, including prevention and protection. There are two ways to deal with disasters. (Modified from http://quake.abag.ca.gov/mitigation/TheRiskMar05.pdf):

1. We can increase emergency response capability. Thus, more damage needs to occur for those capabilities to be exceeded. Large incidents

become manageable emergencies.

2. Projects can be undertaken to prevent or lessen the impacts of future incidents, and thus reduce the need for larger and larger response

capability. Homes can be moved from areas suffering repeated floods. Buildings and infrastructure can be built to reduce expected damage in

earthquakes. Wood shake shingles on homes in fire-prone areas can be replaced with asphalt shingles or tile. These actions are examples of

mitigation.

Mitigation can be defined more specifically as “any sustained action taken to reduce

or eliminate the long-term risk to human life and property from hazards.” As mitigation

activities are undertaken, the effects, extent, or importance associated with disasters can

be decreased.

(From the South Dakota Office of Emergency Management website at

http://oem.sd.gov/mitigation/home.htm): Mitigation Is Not A "Quick Fix." The interest in

initiating change most readily occurs in the immediate post-disaster time period. Public

perception is high and a need for action is most acute. This diminishes rapidly with

the passage of time and the realizations that implementing long-term solutions do not

happen over-night. This, coupled with public concern over the price of such action

(financial, economic, political, and social), often places a damper on completing those

actions in a timely manner or even at all. Nonetheless, the price of inaction outweighs

the cost of corrective action. The expense of reconstruction continues to escalate

annually.

A community that is well-prepared for disasters through preparation and mitigation is said to be resilient – they endure the disaster better and

recover faster than they would have otherwise. This is also a good lesson for individuals and families! Resilient families and individuals are

well-prepared for disasters.

Mitigation Approaches

Mitigation actions are most often thought of as taking the form of structural or non-structural measures. Implementation of mitigation actions

can take either form or a combination thereof. There are primarily four basic approaches to mitigation:

1. Altering the Hazard -- Modifying the hazard to eliminate or reduce the frequency of its occurrence. Triggering avalanches under controlled

conditions and cloud seeding to force premature precipitation to reduce a storm's energy are typical examples.

2. Averting the Hazard -- Redirecting the impact away from a vulnerable location by using structural devices or land treatment to shield people

and development from harm. Dikes, levees, and dams all represent physical efforts implemented to keep the risk away from the people.

3. Adapting to the Hazard -- Modifying structures and altering design standards of construction. Identified problems area such as high wind,

earthquake, land sliding or subsidence, and heavily forested terrain all require special building standards and construction practices in order to

reduce vulnerability to damage.

4. Avoiding the Hazard -- Keep people away from the hazard area or limiting development and population in a risk area. Enforcement actions

such as zoning regulations, building codes and ordinances are intended to restrict, limit, or deny access to specially identified risk areas.

The risks posed by natural hazards can be determined by scientific study. Some kinds of hazards and disasters can be predicted (tornadoes,

hurricanes, floods, volcanic eruptions, landslides, etc.) while others cannot (earthquakes).

The Statistics of Disasters

The natural disasters we study in this course are the result of mankind’s interactions with the natural systems around us – plate tectonics,

magmatic systems, river systems, coastal systems, slope systems, and the atmosphere. On the one hand, we are concerned with how often

hazardous events occur, and on the other we are concerned with how often these events become disasters.

Consider the following two graphs. The earthquake graph is typical of most kinds of natural hazardous events. Before turning the

page, answer to yourself: What do these graphs tell me about 1) how many earthquakes (events) occur over time – is there any

trend? and 2) how will the population trend affect the number of disasters that occur as a result of those earthquakes? What will

graphs of deaths per year and costs of natural disasters look like? Think about these carefully before continuing.

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1 7 13 19 25 31 37 43 49 55 61 67 73 79 85 91 97 103 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Quakes per year, M7.0 and greater 1900 – 2003 (source: USGS Nat’l. Earthquake Info. Center).

As this graph shows, the number of natural disasters is increasing over time. That should come as no surprise when you consider that global

population is increasing and people are spreading into more areas around the world. That naturally exposes more people to risk as time goes by –

more die, and the costs of disasters increases.

NASA

TheEconomist.com

From the National Earthquake Information Center (NEIC):

“Q: Why are we having so many earthquakes? Has earthquake activity been increasing?

A: Although it may seem that we are having more earthquakes, earthquakes of magnitude 7.0 or greater have remained fairly constant throughout

this century and, according to our records, have actually seemed to decrease in recent years. A partial explanation may lie in the fact that in the

last twenty years, we have definitely had an increase in the number of earthquakes we have been able to locate each year. This is because of the

tremendous increase in the number of seismograph stations in the world and the many improvements in global communications.”

Earthquakes raise some valuable questions and illustrate the roles of public perception, increasing global communications, and increasing

scientific instrumentation in understanding natural disasters.

Tsunami damage, northern Japan (USAID)

Think of it this way: How many big events happen in the world today without showing up almost instantly on the internet? Now consider the

same big events happening in the 1920’s – would you have heard about them soon or at all?

Because of instant global communications, we are aware of more events, including disasters, than any generation before us. Naturally, that

causes us to think that there must be more earthquakes, volcanic eruptions, and hurricanes than ever before. The actual statistics show otherwise.

Not only are we aware of more events, but because of increasing scientific instrumentation, we also record more natural events than ever before.

With earthquakes, for example, there were only a dozen or so seismometers in the world a century ago. Today, there are thousands. How, then,

can we compare the number of earthquakes over that long period of time, when we’re obviously recording quakes today that went unrecorded

decades ago? The answer lies in what can be recorded. Earthquakes of magnitude 7.0 and greater are recorded by all the seismometers on earth;

therefore, if we want to compare the number of earthquakes in recent years to the distant past, we must consider only magnitude 7.0 and greater

earthquakes. (In case you’re wondering, the total number of earthquakes of all magnitudes follows the same trend as the 7 and greater quakes).

That’s why the chart on the previous page looks at only large quakes. Beware: there are books and websites out there that ignore this simple

reality, and show incorrect trends. Always turn to the authorities for accurate information and explanations (USGS.gov, NOAA.gov, NASA.gov,

etc.).

Seismometer locations in eastern Idaho and the

Yellowstone region. Each red dot is a

seismometer. Recording small earthquakes

requires a fairly dense network of instruments.

Magnitude Versus Frequency

Large hazardous events (of all kinds) are less frequent than small events, as illustrated by the earthquake chart below. This makes sense from a

practical point of view. A large volcanic eruption, for example, requires accumulation of a large amount of magma, which of course takes a

longer time than a small eruption that involves only a small amount of magma. Similarly, the conditions to form a category 5 hurricane require

specific, rare factors to come together at the same place at the same time, but a smaller hurricane forms more easily.

And so in this course while we study mostly large events, we are personally more likely to experience much smaller versions of them.

USGS/NEIC

http://www.ngdc.noaa.gov/nndc/servlet/ShowDatasets?dataset=102557&search_look=50&display_look=50.

Data Example: Volcanic Eruptions 1900 – 2009

There were 5530 volcanic eruptions worldwide between 1900 and 2009; 238 of those were considered significant by the National Oceanic

and Atmospheric Administration (NOAA). Several of the significant eruptions caused death, injury, loss of homes, and/or economic loss. The

eruptions with the greatest number of deaths, 28000 and 23080, occurred respectively in 1908 and 1985. Data sources: Smithsonian Global

Volcanism Program:

Apply what you have learned so far: Given that this chart only lists known (or recorded) eruptions, what might explain the upward

trend since the 1940’s?

Now consider the following charts. The top one shows events that were large enough to be considered “significant.” The second shows deaths

from “significant” eruptions per year. As expected, the number of events has no trend, but surprisingly the number of deaths does not, either; in

fact, it suggests a slight decrease. This is partly because we have learned how to predict volcanic eruptions and identify volcanic hazards. In

simpler terms, we’re getting better at getting out of the way.

This illustrates another important point: our ability to predict and mitigate hazards of different kinds depends on the type of hazard.

NOAA

NOAA

Before going to the next page, carefully consider this question: From what you have studied so far, what do you think is the trend of

flood disasters over time? Consider the nature of floods, the relationships between cities and rivers, our interactions with river systems

(in ways we do not interact with quakes and eruptions), and population growth. Now go to the next page and see if your prediction was

correct!

St. Mark’s Square, Venice, Italy, 2012 source: the Atlantic.com

(http://www.emdat.be/advanced-search

Data Example: Floods

Hopefully, you’re not surprised by this graph!

Cities and towns have historically been built along rivers for the supply of drinking and farming water and the trade, communications, and fertile

soils they provide. As populations grow, we spread into more and more areas, including flood plains, and we modify river systems. As you will

learn in future chapters, urban development also increases the severity of flooding. And so flood disasters are increasing with time.

The Economic Effects of Disasters It may not seem obvious at first, but the answer to this question is quite up for debate: “Are disasters good for the economy?” As populations

increase and more people move into harm’s way, this question is gaining interest. In this discussion “capital” refers to human, natural, or physical

resources. Human capital is the labor force – the people available to work. Natural capital refers to water, fuels, land, crops, lumber, metals, and

so forth. Physical capital refers to roads, utilities, factories, stores, railroads, and so forth.

Disasters change the mix of human and physical capital, but in different ways depending on the details of the disaster. A plague, for example, can

reduce the number of people available to work while leaving physical facilities and resources untouched. A hurricane, on the other hand, can

destroy physical facilities while leaving the evacuated labor force intact. Earthquakes, large volcanic eruptions, and floods, on the other hand,

tend to destroy both human and physical capital. Below is the summary of arguments on both sides.

Yes, Disasters Are Good for the Economy source

1. Reconstruction stimulates the construction sector.

2. Facilities and infrastructure destroyed in a disaster are usually rebuilt to higher standards and with improved technology, leading to higher

productivity and efficiency. This leads to long-term economic improvement.

3. Reconstruction money (grants) stimulates short-term growth throughout the affected community, not just in the construction sector.

4. Because we are getting better at forecasting atmospheric disasters (tornadoes and hurricanes) and death tolls from those disasters are smaller

than in the past, meaning the human resources toll is smaller, reconstruction and improved infrastructure and facilities result in a net economic

benefit.

5. When a disaster reduces labor capital, there are more physical and natural capital available per person, resulting in increased economic output

and wealth per capita.

No, Disasters Are Bad for the Economy source

1. When a disaster results in large-scale relocation of people and resources, the affected area’s economy shrinks (example: Hurricane Katrina).

2. As a general principle, societies cannot be made wealthier by destroying resources. Otherwise, Beirut would be one of the wealthiest places on

earth.

3. Disasters make resources scarce – labor, capital, physical facilities, and natural resources – thereby reducing economic output.

4. When physical capital is destroyed but labor capital is unaffected, economic output falls and per capita wealth decreases.

Be prepared to discuss this topic as we explore case studies throughout the semester.

We will apply these foundational definitions, concepts, statistics, and ideas to

natural hazards of various kinds throughout the semester.

Next: Plate Tectonics

Tolbachik volcano eruption, Kamchatka, 1975, by Vadim Gippenreiter