Download Hazardous Environments

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
Economic
Growth
Pressure to
develop
marginal land
Urbanisation
Increased
Impacts
of ENE’s
Government
inability to
cope
Failure to
recognise
potential hazards
Common Characteristics of
Natural Hazards
Natural hazards and their effects on people
tend to have common characteristics:
1.
The origin of the hazard is clear and produces
characteristic effects.
2.
Warning time is normally short (except for drought) i.e.
they are rapid-onset unscheduled events.
3.
Most loss of life and property are suffered during or
soon after the event.
4.
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)
5.
The impact on the human population has an intensity
and scale to justify an emergency response.
Risk levels: LEDC’s vs MEDC’s
LEDC
MEDC
•Large / poor populations
•Large built environment
•Inadequate infrastructure
(greater risk of damage)
•Ineffectual governments
•Larger investment risk
•Extreme climate
•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.
Purposes of classification:
1.
Assessing risk
2.
Understanding spatial patterns
3.
Understanding how hazards impact on people
4.
Aiding our understanding of processes and how
they are inter-related
5.
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)
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”
•
This approach thus has 2 essential elements:
1.
2.
Risk Assessment
Risk Communication (between all concerned)