Geography 2152: Midterm (Full set)

Hazards

Hazards affect millions of people around the world each year. Within North America, every location is at risk from at least one hazard process. Some hazards pose a risk to both humans and the environment. Examples; Nuclear meltdowns, Toxic gas release, Oil spills, Ozone depletion, Acid rain, Infrastructure failure, Shipwrecks, Airplane crash

Areas in North American Impacted by Hazards

1. West coast: earthquakes, landslides

2. East coast: hurricanes, tropical storms

3. Mid-continent: tornadoes, blizzards

4. All areas: drought

Natural hazards can arise from 3 main processes

1. Internal forces within the Earth (crust, mantle). Driven by the internal energy of the earth. Ex; plate tectonics

2. External forces on Earth's surface. Driven by the sun's energy. Ex; atmospheric effects

3. Gravitational attraction. Driven by the force of gravity. Ex; downslope movement

Hazard definition

A process that possesses a potential threat to people or the environment

Risk definition

The probability of an event occurring multiplied by the impact on people or the environment

Disaster definition

A brief event that causes great property damage or loss of life

Catastrophe definition

A massive disaster

Examples of recent catastrophes

1. Hurricane Katrina 2005

2. Indian ocean tsunami (Thailand 2004)

3. Japan earthquake which caused a nuclear meltdown and a tsunami in 2011

4. Earthquake in Haiti in 2010

5. Oil Spill in Gulf of Mexico in 2010

Hazards as potential catastrophes

1. More likely to be catastrophic: tsunamis, earthquakes, volcanoes, hurricanes, floods

2. Less likely to be catastrophic: landslides, tornadoes, avalanches, wildfires

Magnitude and frequency

The impact of a hazard is a function of both its magnitude (i.e. energy released) and frequency. It can also be affected by other factors (geology, land use, population density etc)

Magnitude frequency concept

There is an inverse relationship between magnitude and frequency; as one variable goes up, the other goes down

The geologic cycle

1. Tectonic cycle

2. Rock cycle

3. Water cycle (hydrologic)

Tectonic cycle

This cycle involves the creation, movement, and destruction of tectonic plates. The process is driven by Earth's internal energy

Tectonic plates

Large blocks of the earth's crust that form its outer shell; there are 14 plates (7 big ones and 7 small ones). New land is formed at mid-ocean ridges and land is destroyed at subduction zones

Earth's internal structure

1. Lithosphere; thin brittle crust

2. Asthenosphere; (upper mantle) is composed of hot magma with some flow

Plate tectonics

The crust forms the upper part of the lithosphere and is broken into fragments (plates). Movement of the plates is caused by convection currents within the mantle.

Oceanic vs Continental plates

If the continental plate and oceanic plate collided, which one would sink? The answer is the oceanic plate would sink because it is more dense. When the plate sinks, the rock is melting and the currents are carrying the melted rock up through the continental crust which can cause volcanoes. Vancouver is prone to earthquakes and volcanoes because these plates are colliding

1. Oceanic: dense, thin (averages 7 km thickness)

2. Continental: relatively buoyant, thick (averages 30km thickness)

Plate boundaries

Plate boundaries do not tend to match up with the boundaries of continents or oceans. The movement of plates causes dynamic events on earth's surface, especially at plate boundaries

Types of plate boundaries

1. Divergent

2. Convergent

3. Transform

Pangaea and plate tectonics

The continents of today were clustered into the supercontinent of Pangaea 250 million years ago. Evidence for this includes current mountain ranges

Divergent plate boundaries

At these boundaries, plates move away from each other. New land is created at these locations. Divergence results in seafloor spreading and causes oceanic ridges to form (ex; mid-atlantic ridge). The Atlantic Ocean is getting wider by a few cm every year

Convergent plate boundaries

At these boundaries, plates move toward each other. Subduction zones and collision boundaries

Subduction zones

Collisions involving oceanic and continental crust result in this. Dence ocean plates sink and melt (oceanic plate). The melted magma rises to form volcanoes

Collision boundaries

Collisions involving two continental plates result in this. Neither plate sinks. Tall mountains tend to form (ex; Himalayas). Ex; India and Continental Asia (mount Everest)

Transform boundaries

At these boundaries, plates slide horizontally past each other. The zone along which the movement occurs is called a transform fault. Most of these faults are located beneath oceans, but some occur on continents. Ex: San Andreas

Hot spots

These areas are found away from plate boundaries. They are spots where magma rises up from the mantle. Magma erupting at the surface results in the formation of volcanoes. Strings of islands are usually indicative of a hot spot. Ex: Hawaiian islands

The rock cycle

A rock is an aggregate of one or more minerals. The rock cycle refers to a group of interrelated processes that produce the three different rock types: igneous, sedimentary, metamorphic. In a given location, the types of rock gives clues to geological events of the past

The hydrologic cycle

The movement and exchange of water among the land, atmosphere and oceans by changes in state. It is also referred to as the water cycle. Solar energy drives the movement of water among the atmosphere, oceans, and continents.

Residence time

The residence time of a water molecule ranges from days (in the atmosphere) to thousands of years (in the ocean)

Major course themes

1. Hazards can be understood through scientific investigation and analysis.

2. An understanding of hazardous processes is needed to evaluate risk.

3. Hazards are linked to each other and the environment

4. Population growth and socio-economic changes are increasing the risk from hazards.

5. The consequences of hazards can be reduced

Hazards can be understood

Scientists observe a hazardous event and form a possible explanation for the cause. From this explanation, a hypothesis is formed. Data is then collected to test the hypothesis. Knowing the cause allows for the identification of where hazards may occur. Knowledge of past events aids in predicting future events

Many hazards are natural processes

These events are natural forces; they only become hazardous when they disrupt human activity or the environment. These process are not within our control; we cannot prevent them, we can only respond to them and try to reduce the impact. The best solution is to try to mitigate loss

Mitigating loss

Accurate predictions and forecasts are necessary in order to reduce loss. Some hazards can be predicted but most can only be forecasted

1. Prediction: a specific time, date, location, and magnitude of the event

2. Forecast: a range of probability for the event

Understanding hazardous processes to evaluate risk

1. Risk = (probability of event) x (consequences).

2. Consequences: damage to people, property, the environment, the economy

3. Acceptable risk is the amount of risk that an individual or society is willing to take. The frequency of an event plays a role in determining the acceptable risk

Hazards are linked

Hazards are linked to each other. Examples include earthquakes that cause a tsunami or landslide. Hurricanes may cause tornadoes and flooding. Some environments are linked to certain hazards. Examples include some rock types are more prone to landslides

The increasing risk of hazards

Concentration of human population creates greater loss of life in a disaster. Population growth is putting greater demand on earth's resources. Rapid population growth is currently occurring in more developing countries. Many people live in areas that are prone to hazards.

The human footprint

The risks associated with hazards change as human development expands. Examples include Neighbourhoods extend onto hillsides and floodplains. Urbanization alters drainage and slopes. Agriculture, forestry, and mining can increase erosion. In Canada, property damage from hazards is increasing but deaths from hazards are decreasing (because of better planning and warning).

Socio-economic factors

Economic losses from disasters are much higher in developed countries. Deaths from disasters are much higher in developing countries.

Consequences can be reduced

The effects of a disaster may be either direct or indirect. We mainly deal with effects in reactive ways. But a higher level strategy requires a proactive approach

1. Direct effects: deaths, injuries, displacement or people, damage to property

2. Indirect effects: crop failure, starvation, emotional distress, loss of employment

Reactive approaches to hazards

These involve recovery, search and rescue, providing emergency food, water, shelter and rebuilding

Proactive approaches to hazards

Involves adjustment through:

1. Land use planning building codes (ex; japan and California have strict building codes)

2. Insurance (ex; California has fire insurance)

3. Evacuation planning

4. Disaster preparedness

5. Artificial control (ex; concrete flood wall/levis)

Benefits of hazardous events

Some natural events provide important benefits. What are these benefits called? Natural service functions. Examples include;

1. Flooding provides nutrients for soil

2. Landslides form natural dams that create lakes

3. Volcanic eruptions create new land

Climate change and natural hazards

Global climate change is currently the most crucial environmental issue facing the Earth. As climate changes, the frequency of some natural processes will increase. The sea level rise from melting ice sheets will cause more coastal erosion and flooding. Warmer oceans will cause more frequent hurricanes

Documenting disasters

Maintaining databases on disaster events can be difficult. Why? Disasters can co-occur (hurricanes cause floods, earthquakes cause landslides etc). Mortality can be difficult to count (famine, countries). A general lack of census taking (in developing countries)

Defining disasters

10 or more deaths per event OR 100 or more people affected in a serious way (injured, homeless) OR

Governments declaration of disaster OR Plea for international assistance. Developed by the Centre for Research on the Epidemiology of Disasters (CRED)

Exceptions to the CRED threshold

For droughts or famines, at least 2000 people affected. For technological disasters, 5 or more deaths per event

Disasters and statistics

Statistical data is reported in absolute terms (number of casualties, billions of dollars in damage, etc). The impact of losses is felt differently from one place to the next. Example: 10 fishers lost in a remote village of 200 people versus 10 factory workers in a city of 200,000. Therefore, statistics must be placed in a community/regional context

Media and disasters

The media tends to concentrate on:

1. human interest

2. visual impact

3. events prioritized according to a North American perspective. In terms of North American media attention, a study found that an event causing the death of one North American was granted the same amount of reporting time to the deaths of: 3 Eastern Europeans, 9 Latin Americans, 11 Middle Easterners, and 12 Asians

Disasters and impacts

Impacts vary greatly by disaster type. Examples include; earthquakes tend to cause more deaths than tornadoes, floods affect more people (homelessness) than most disasters but cause fewer deaths, droughts only cause economic losses (agriculture) in developed countries but they can lead to famine in developing countries, technological disasters are more likely to occur in developed countries

Disaster impact trends

Globally, most impacts from disasters have increased over time:

1. property damage

2. economic losses

3. persons injured

4. deaths

Impacts have not increased in equal proportions. Economic losses have increased at a faster rate than deaths

Haiti Earthquake

Haiti has been the poorest country in the western hemisphere for many years. The M7.0 earthquake occurred on Jan. 12, 2010. It was one of the worst natural disasters in history; the death toll was over 160,000. The epicenter was 25 km from port-au-prince (the capital city). Most buildings were destroyed. The earthquake occurred along a transform fault. The destruction was enhanced by poor construction materials and a lack of building codes. Landslides affected slums in the hillsides surrounding the city. The 2nd floor of the presidential palace collapsed as did the prison allowing 4000 inmates to escape

Reasons for increases in impacts

1. Land pressure

2. Urbanization

Land pressure

Approximately 1 billion people live on degraded land. Poverty and lack of land availability leads to unsustainable farming practices. Examples include; soil erosion, deforestation, clearing mangroves for monoculture

Mangroves vs Monoculture

Mangroves can protect land against storm surges, Monoculture results in a loss of bio diversity

Urbanization

Around the world, people are increasingly moving from rural areas to urban areas. Slums and squatter settlements are rapidly growing in developing countries

Vulnerability to disasters

The vulnerability for a particular location is a function of its resiliency and reliability. Both resiliency and reliability tend to be lower in developing countries

Resiliency

The rate of recovery from the occurrence of an event; how quickly you can bounce back from something

Reliability

The frequency with which protective devices against disasters are able to withstand the disaster

Risk assessment

Involves estimating the likelihood that a particular event will harm human health

1. Hazard identification

2. Probability of risk

3. Consequences of risk

Risk management

Involves deciding whether or how to reduce a particular risk at a cost

1. Comparative risk analysis

2. Risk reduction

3. Risk reduction strategy

4. Financial commitment

Risk

Risk is viewed by individuals as subjective. What we as individuals consider to be risky is based on our own probabilistic risk assessments. Risk assessments are not a modern phenomenon. Example: There are religious examples that aim to assess the risk to the soul based on moral conduct

Risk assessment data issues

1. Event data; It is best to have at least 100 years of data. This amount of data is not available for several hazards (high-magnitude earthquakes, nuclear accidents etc)

2. Economic loss data; This is often less available than event data. There are many currencies worldwide; values must constantly be adjusted for inflation

Statistical analysis

R = P * L

R = risk

P = probability of hazard occurrence

L = loss (economic, health, etc.)

Interpreting Probabilities:

Cumulative probabilities sum to 1 therefore we can read each probability as a percent. Example: if an event has a probability of 0.01, that event has a 1% chance of happening

Risk analysis event trees

These may be used when the event database is inadequate (too small). The chain of events leading to a disaster must be known. Probabilities within the chain must be calculable

Estimating risk

What is the risk associated with a technological system? The overall reliability of a technological system is the product of two factors: System reliability = Technology reliability x Human reliability. Human reliability is usually lower than technology reliability and is difficult to predict. Example; Suppose the technological reliability of a nuclear power plant is 95% and the human reliability is 75%. The overall system reliability is then 71% (0.95 x 0.75 = 0.71)

Risk analysis

The greatest risk factor leading to a reduction in life expectancy is poverty. Poverty is linked to:

1. malnutrition

2. increased susceptibility to fatal diseases

3. lack of access to health care

4. contaminated water supplies

The effects and indirect benefits of poverty reduction

The reduction of poverty would lead to increased life expectancy and improved human health. Indirect benefits of reducing poverty:

1. stimulates economic development

2. reduces environmental degradation

3. improves human rights

Risk perception

Risks are generally not well perceived by people. Many people are not concerned with high-risk activities that are done voluntarily. Examples include:

1. Smoking (1 premature death per 2 participants)

2. Motorcycling (1 per 60)

3. Driving a car (1 per 4200)

Factors influencing risk perception

Risks from hazards are more accepted by people if the risks are perceived to:

1. Be voluntary vs imposed

2. Be under our control vs controlled by others

3. Have clear benefits vs little or no benefit

4. Be natural vs anthropogenic

5. Be statistical vs catastrophic

6. Be familiar vs exotic

7. Affects adults vs children

Improving our risk perceptions

How can we become better at perceiving risks?

1. Carefully evaluate what the media presents

2. Compare risks (the question is not 'is it safe' but rather 'how risky is it compared to other risks)

3. Concentrate on the most serious risks to your own health and don't worry about risks over which you have no control

The changing nature of risk

There has been a shift in the nature of risks over the last few generations:

1. shift from infectious diseases toward chronic degenerative diseases

2. accidents shift from being more common in the workplace to rare due to improved safety regulations

3. death rates from natural disasters are generally lower than they were in the past in developed countries

4. as technology has advanced, it has introduced new hazard threats (ex; nuclear power plants, chemical spills, pesticides etc)

5. increased involvement of the government and laypeople in risk assessment and management (ex; disaster relief departments, Sierra Club or Greenpeace)

6. as countries transition from developing to developed, there are increased expectations on their government from the public

Tsunamis

Tsunami is Japanese for "harbour wave". They are produced by the sudden displacement of water.

Events that trigger tsunamis

1. Earthquakes that cause uplift of the seafloor

2. Landslides

3. Volcano flank collapse

4. Underwater volcanic eruptions

5. Meteorites

Historic tsunamis

1. Lisbon earthquake 1755 (M 9.0), Portugal, 20,000 casualties

2. Krakatoa Volcanis Eruption 1883, Indonesia, 36,000 casualties

3. Sumatra Earthquake 2004 (M 9.1), Indonesia, 230,000 casualties

4. Tohoku Earthquake 2011 (M 9.0), Japan, 16,000 casualties

Earthquake triggered tsunamis

Earthquakes can cause tsunamis in two ways:

1. by displacement of the seafloor

2. by triggering a landslide that enters water

Generally, an earthquake must be of at least M 7.5 in order to trigger a tsunami. Tsunamis develop in four stages

Four stages of tsunami development

1. Displacement of the seafloor sets waves in motion that transmit energy upward and outward. When the waves reach the surface of the water, they spread outward

2. The waves move rapidly across the open ocean (they can reach speeds of over 500 km/h). The spacing of the wave crests is very large (it can be more than 100 km). The height (amplitude) of the waves is often small (less than 1 m). Passengers on ships in the ocean rarely even notice tsunamis passing beneath them

3. As the tsunami approaches land, the water depth decreases. This results in the water 'piling up' and causes these effects: a decrease in wave speed, a decrease in spacing of the waves, an increase in wave amplitude

4. As the tsunami impacts land, waves can reach heights of dozens of metres. The wave speed at this time can be up to 50 km/h making them impossible to outrun. During some tsunamis, the water first recedes from the shore and exposes the seafloor

Tsunami event

A tsunami event consists of a series of large waves reaching shore that can last for several hours. Run up

Run up

The maximum vertical distance that the largest wave of a tsunami reaches as it travels inland.

Types of tsunamis

1. Distant tsunami

2. Local tsunami

Distant tsunami

A tsunami that travels thousands of kilometres across the open ocean. On remote shorelines across the ocean, reduced energy lessens its impact. They are also called tele-tsunamis

Local tsunami

A tsunami that affects shorelines a few kilometres to about 100km from its source. Because of this short distance, local tsunamis provide little warning

Regions at risk of tsunamis

Coasts located near subduction zones or across oceans from subduction zones are most at risk. Areas at greatest risk are the pacific ocean and the Mediterranean sea

Primary effects of tsunamis

Flooding and erosion destroy beaches, coastal vegetation and infrastructure. After the tsunami retreats to the ocean, scattered debris is left behind. Most tsunami deaths are from drowning. Injuries result from physical impacts with debris

Secondary effects of tsunamis

These are effects that generally occur after the event is over. Fires may develop due to ruptured gas lines or from ignition of flammable chemicals. Water supplies may become contaminated and water-borne diseases (cholera) may spread

Indian Ocean tsunami 2004 (Sumatra earthquake)

This catastrophic event occurred on Dec. 26th. The source was a M 9.1 earthquake off the west coast of Sumatra (an island in Indonesia). It was the third strongest earthquake in world history. The earthquake occurred in a subduction zone between the Burma and Indian-Australian plates. These plates had been locked for over 150 years thus allowing strain to build. The rupture caused some land areas along the coastline to subside below sea level. The tsunami reached nearby Indonesian islands within minutes of the earthquake. Many coastal communities in Indonesia and surrounding countries were heavily damaged during the event. Countries bordering the Indian Ocean did not have a tsunami warning system like those bordering the Pacific Ocean. People were caught by surprise and over 230,000 died. Many were unfamiliar with tsunamis and some were intrigued by the approaching waves. Most people in the area were ignorant of an early warning sign (the receding sea)

Lessons from the 2004 tsunami

Effective tsunami warning systems are needed around all oceans where tsunamis can occur. In 2006, a new warning system became operational in the Indian Ocean. A warning system by itself is not enough. Why? Because emergency officials must have an organized plan for evacuating residents during a warning and earthquake and tsunami education is necessary for people who live along or visit coastlines

Detecting tsunamis

The Pacific Ocean warning system uses a network of seismographs to estimate earthquake magnitude. Sensors electronically connected to buoys verify that a tsunami was produced. They rest on the seafloor and measure changes in water pressure passing over them. These sensors are called tsunameter

Structural control

Damage can be minimized through regulations on buildings and structures. Some cities in Hawaii require flood proofing measures such as basement window sealing and bolting homes to their foundation. Concrete levees are other preventative measures but can be very expensive. Offshore barriers are only feasible outside cities with very large populations

Inundation maps

Maps showing the geographic area that can be potentially impacted by tsunamis are created to help plan for future events. Historical records, geologic data, and aerial photography aid in making the maps. Many north American cities on the pacific coast have such maps and development restrictions may exist there in areas at high risk of tsunamis

Land use

Vegetation plays a role in determining tsunami damage.In areas impacted by smaller waves, trees and dense vegetation protect areas farther inland

Japan tsunami of 2011

This catastrophic event occurred on March 11th.

The source was a M 9.0 earthquake 70km off the east coast of Japan. A tsunami warning was issued nearly an hour before its arrival. Over 15,000 people died and damage to Japan's infrastructure was extensive

Categories of adjustment

1. Modify the Loss Burden; loss sharing, spread the burden well beyond immediate victims (ex; relief aid, insurance)

2. Modify Design; loss reduction, requires a knowledge base of the hazard (ex; retrofitting buildings)

3. Modify Human Vulnerability; adjust the population to the possible events (ex; warning systems, preparedness programs)

Factors affecting adjustment choices

Hazards are not typically a priority of governments (compared to unemployment, inflation, health care, crime, poverty, etc.). Radical vulnerability adjustments are unrealistic (e.g. moving entire communities). A cost-benefit assessment is typically required

Two scenarios of losses

1. Accepting loss

2. Sharing loss

Accepting loss

This is the 'free' choice. It is a no-action response. People choose to live how they want regardless of the hazard risk but aid may not be provided after a disaster. Example: floodplain housing can be attractive because it may be inexpensive

Sharing loss

This is the government-action response. There may be laws in place preventing people from living in certain areas. If governments do not intervene after a disaster, there are often political ramifications. Aid can come from external sources (UNICEF), internal sources (government), inter-community sources (local), and insurance

Problems with sharing loss

1. A disaster of sudden onset is likely to draw more money than another similarly serious disaster

2. Donor fatigue can set in if there are many disasters

3. Recovery can take a very long time in some countries

4. Aid and enthusiasm to donate eventually wanes

Factors affecting individual adjustment choices

1. Experience; More experience with a hazard results in more likelihood of adjustment

2. Material wealth; More resources results in more information and more options

3. Personality; Some people are more likely to take risks. Some people have more confidence than others

Prospect theory

Generally, people are more willing to protect against a loss than they are willing to gamble on an equivalent gain

Human responses to hazards

1. Cultural adjustment

2. Purposeful adjustment

3. Incidental adjustment

4. Absorptive capacity