Hazardous Environments

Introduction

Curriculum

3.1 Hazardous Environments resulting from Crustal (tectonic) Movement

• Global distribution and the relationship of hazards to plate tectonics (convergent, divergent, conservative plate margins, hot spots); • earthquakes and resultant hazards (shaking, landslides, tsunami); • volcanic hazards; types of eruption and their products (nuées ardentés, lava flows, mudflows, pyroclastic and ash fallout); • prediction and monitoring of hazard; perception of risk. • Effects on lives and property.

3.2 Hazardous Environments resulting from Mass Movements

• Nature and causes of mass movements on slopes leading to hazards that result from slope instability, level of impact; • the nature and causes of avalanches and the hazards produced; • prediction and monitoring of the hazard and the perception of risk. • Effects on lives and property.

3.3 Hazard resulting from Atmospheric Disturbances

• Distribution of areas most at risk from tropical storms and tornadoes; • processes causing the development of tropical storms and tornadoes; • related hazards (Coastal flooding, severe river floods, landslides, storm surges, high winds, pressure imbalances). • Prediction, monitoring of hazards and perception of risk. • Effects on lives and property.

3.4 Sustainable Management in Hazardous Environments

• A case study illustrating some of the problems of sustainable management of a hazardous environment and an evaluation of attempted or possible solutions.

What Is a Hazard?

• A Hazard is an event that threatens life and/or property.

Extreme Natural or Cultural Events H A Z A R D People and/or their property

Natural Hazards

• Extreme natural events that originate in the lithosphere, the atmosphere or hydrosphere (tectonic/geologic, surface or atmospheric) that risk damage to people and/or property.

Cultural Hazards

• Events caused by humans; technological (explosions, contamination etc) and social (riots, crime, terrorism) that risk damage to people and/or property.

Disaster

• John Whittow in his book ‘Disasters: The Anatomy of Environmental Hazards’ suggested that:

“a hazard is a perceived natural event which threatens both life and property – a disaster is the realisation of this hazard”

• Disasters are therefore extreme events that normally cause great loss of life and/or damage to the built environment and create severe disruption to human activities.

Risk Assessment

• The process of establishing the probability that a hazard event of a particular magnitude will occur within a given period.

Integrated Risk Management

• The process of considering the social, economic and political factors involved in risk analysis; determining the acceptability of damage/disruption; deciding on actions to be taken to minimise damage/disruption.

Vulnerability

• Is the potential for losses or other adverse impacts. People, buildings, ecosystems and human activities threatened with disaster are vulnerable.

IDNDR

• (International Decade for Natural Disaster Reduction) • Set up by United Nations in 1989 with a multisectoral framework of action with the aim

‘to reduce the loss of life, property damage and socio-economic disruption caused by natural, technological and environmental disasters’

• IDNDR conclusions: – Recent hazards impacts have dramatically increased (however frequency of extreme natural events has not).

– Risk has increased due to increasing cultural exposure to extreme natural events.

Population Growth Urbanisation Economic Growth Pressure to develop marginal land Increased Impacts of ENE’s Government inability to cope Failure to recognise potential hazards

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Common Characteristics of Natural Hazards

Natural hazards and their effects on people tend to have common characteristics: The origin of the hazard is clear and produces characteristic effects.

Warning time is normally short (except for drought) i.e. they are rapid-onset unscheduled events.

Most loss of life and property are suffered during or soon after the event.

The risk is involuntary (although this applies mainly to LEDC’s as most people in MEDC’s are aware of risks and choose to minimise or ignore them) The impact on the human population has an intensity and scale to justify an emergency response.

Risk levels: LEDC’s vs MEDC’s

LEDC

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Large / poor populations

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Inadequate infrastructure

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Ineffectual governments

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Extreme climate MEDC

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Large built environment (greater risk of damage)

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Larger investment risk

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Highly urbanised

Hazard Classification

Hazards have been classified using a wide range of criteria and approaches, and for a variety of purposes and user groups.

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Assessing risk Understanding spatial patterns Understanding how hazards impact on people Aiding our understanding of processes and how they are inter-related Helping to manage responses to hazards Classification groups include: – Spatial distribution e.g. MEDC/LEDC, Continents or climate region – – Origin/causal process e.g. tectonic, atmospheric Impact on people e.g. levels of damage

Hazard Frequency & Magnitude(Scale)

• Hazards are commonly classified using their frequency and magnitude.

Magnitude: (size) – most commonly seen with earthquakes (Richter and Mercalli scales) or tropical cyclones (Beaufort scale for wind speed & Saffir-Simpson scale) Frequency: (how often they occur) – Storms and floods are often classified using a ‘recurrence interval’ e.g. 100 year flood. This is a probability statement not a temporal staement. • There is a statistical relationship between magnitude and frequency: “as magnitude increases frequency decreases.”

Saffir – Simpson Scale

Effects, Risk & Perception

Effects • Effects can be split into ‘environmental & cultural’ or ‘primary & secondary’ • Risk

People put themselves at risk because:

– Hazards are essentially unpredictable – Lack of alternatives (due to social, political, economic or cultural factors) – Changing levels of risk – Cost/benefit (benefits outweigh the risk/cost) – Perception Perception – Fatalism (acceptance of hazard – God’s will) – Adaptation (modify lifestyle to minimise effects) – Fear (forces people to relocate away from risk)

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Management of Hazards

Response to hazards has shifted from just coping to a sophisticated ‘integrated risk management approach.

This approach supported by the UN & IDNDR combines ‘Prediction, Prevention & Protection’.

Britton (1998) defined ‘Integrated Risk Management’ as

“the process of considering the social, economic and political factors involved in risk analysis; determining the acceptability of damage/disruption; deciding on the actions to be taken to minimise damage/disruption”

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This approach thus has 2 essential elements: Risk Assessment Risk Communication (between all concerned)