1GS135 GEOLOGICAL HAZARDS

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• 1GS135 GEOLOGICAL HAZARDS ENGINEERING GEOLOGY

SCHOOL OF EARTH ENVIRONMENTAL
SCIENCES Workshop 1 How do we describe
Geohazards and ground related risks?
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Hazard, Vulnerability Risk

• 1. As a group decide on a formal definition for
  HAZARD

Results 1 - 18 of about 198,000 for hazard
definition.
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Hazard, Vulnerability Risk

• 2. As a group decide on a formal definition for
  VULNERABILITY

Results 1 - 18 of about 29,700 for vulnerability
definition.
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Hazard, Vulnerability Risk

• 3. As a group decide on a formal definition for
  RISK

Results 1 - 18 of about 779,000 for risk
definition.
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Hazard, Vulnerability Risk

• 4. Consider how you think RISK and HAZARD are
  related ?

Results 1 - 18 of about 4,240 for hazard and
risk.
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Hazard, Vulnerability Risk

• Consider how you think RISK, VULNERABILITY and
  HAZARD are related ?

Results 1 - 18 of about 86 for hazard,
vulnerability and risk.
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Hazard, Vulnerability Risk

• 5. Define a DISASTER ?

Results 1 - 18 of about 428,000 for disaster
definition.
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Hazard, Vulnerability Risk

• 6. Define a NATURAL DISATER.

Results 1 - 18 of about 12,500 for natural
disaster.
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Hazard, Vulnerability Risk

• 7. Is the world becoming a more dangerous place ?
  What factors make us more susceptible ?
• 8. In which region of the world would YOU not
  live due to the presence of extreme hazards?

Results 1 - 18 of about 383 for extreme hazard.
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Hazard, Vulnerability Risk
Over to You
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Hazard, Vulnerability Risk

• 1. As a group decide on a formal definition for
  HAZARD
• Hazard
• Potential for adverse consequences
• Potential to cause harm
• In particular circumstances
• Hazardous Situation
• Hazardous Event
• A trigger which exposes a person to harm
• Hazard Analysis

" A condition with the potential for causing
harm.... Poisonous chemicals are an example of
hazard "Engineering Council 1993
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Hazard, Vulnerability Risk

• 2. As a group decide on a formal definition for
  VULNERABILITY

What is vulnerability? Vulnerability is the
susceptibility of resources to negative impacts
from hazard events. It is these negative impacts
that concern most people. While the study of
hazards, risks, and probabilities is an important
component of vulnerability, alone it does not
provide resource managers with the information
necessary to prioritize mitigation alternatives
or measure improvements in mitigation. In order
to make efficient use of your mitigation
resources, it is not enough to know if, when, or
even where a hazard event will strike. You need
to know where your vulnerabilities are so you can
make the most of your pre-disaster planning
efforts.
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Hazard, Vulnerability Risk

• 3. As a group decide on a formal definition for
  RISK
• Chance of a defined hazard occurring
• Combines the probability or frequency of the
  occurrence of the hazardous event with a measure
  of the consequences of that event

" Risk is an objective measure of the likelihood
of a specific undesired event and its unwanted
consequences or loss "Engineering Council 1993
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Hazard, Vulnerability Risk
What is risk? The following formula best defines
risk RISK Hazard Elements at Risk
Vulnerability The concept of risk combines our
understanding of the likelihood of a hazardous
event occurring, with an assessment of its
impact. Hazardous events can either be naturally
occurring, such as earthquakes, tropical cyclones
or coastal erosion or they can be man-made, such
as water pollution, or terrorist attack.
Moreover, events can be sudden, as in the case of
an earthquake or they can occur over a period of
time, as in the case of most environmental
hazards. The impact of a hazardous event depends
on the elements at risk, such as population or
buildings, and their associated vulnerability to
damage or change as a result of the event.
Estimating risk is an uncertain science because
it involves forecasting future events whose time
and location of occurrence may be largely
unknown. We capture this uncertainty
mathematically in terms of probability. The
risk, hazard, exposure, vulnerability
relationship The total risk may be decreased by
reducing the size of any one or more of the three
contributing variables - the hazard, the elements
exposed and/or their vulnerability. This can be
illustrated by assuming the 'dimension' of each
of the three variables represents the side of a
triangle, with risk represented by the area of
the triangle. In the image above the larger
(yellow) triangle portrays each of the variables
as being equal, whilst in the smaller (green
hachure) triangle the total risk has been
mitigated by halving both exposure and
vulnerability. The reduction of any one of the
three factors to zero would consequently
eliminate the risk.
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Hazard, Vulnerability Risk
What is risk? The following formula best defines
risk RISK Hazard Elements at Risk
Vulnerability The risk, hazard, exposure,
vulnerability relationship The total risk may be
decreased by reducing the size of any one or more
of the three contributing variables - the hazard,
the elements exposed and/or their vulnerability.
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Hazard, Vulnerability Risk

• 5. Define a DISASTER ?

Results 1 - 18 of about 428,000 for disaster
definition.
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Hazard, Vulnerability Risk

• 6. Define a NATURAL DISATER.

Results 1 - 18 of about 12,500 for natural
disaster.
18
Hazard, Vulnerability Risk

• 7. Is the world becoming a more dangerous place ?
  What factors make us more susceptible ?
• 8. In which region of the world would YOU not
  live due to the presence of extreme hazards?

Results 1 - 18 of about 383 for extreme hazard.