Module One: Introduction to Natural Hazards

Endogenic Processes

Driven by Earth’s Internal heat, portions of the rock cycle, tectonics, earthquakes, atmospheric and oceanic circulation, volcanism, and tsunamis

Exogenic Processes

driven by the insolation of incoming solar radiation: portions of the rock cycle, hydrologic cycle, atmospheric and oceanic circulation, severe storms, river floods, coastal erosion.

Processes driven by gravity

landslides, snow avalanches, river flow.

Principle of environmental unity

one process is always associated with another. Hazards are commonly linked to each other as well as the environment in which they occur.

Hazard

A natural process that poses a potential threat to people and property.

Risk

derives from the combination of hazards, exposure, vulnerability, coping capacity

Exposure

Overlap of hazardous process with human population and ore infrastructure. People put themselves in harms way often.

Vulnerability

Susceptibility of human populations and property to a hazardous event.

Coping Capacity

Ability of populations to respond to and or reduce negative impacts of a hazardous event. How Quickly can we recover? how easily?

Mitigation

Preplanning for an event.

Reoccurrence Interval

Estimate of the interval of time, in years, between events of certain magnitude. (they can still happen back to back)

Likelihood

An estimate based on previous events, referring to the chance of a hazard in a specific amount of time ( magnitude, timing, place)

Cost

Refers to the impact of a particular hazard. Damage to property and infrastructure and people.

Natural Disaster

A hazard that kills 10 or more people, 100 people are affected, appeal of national or international assistance, historically significant, damage/interruption of normal processes such that the community affected cannot recover on its own. (Emergency Management Framework for Canada)

Catastrophes

Associated with large numbers of casualties, and destruction of infrastructure along with affecting areas well beyond the directly affected region and recovery will demand large and long-term expenditures of time, human effort, and money.

Magnitude

Refers to the strength/intensity of the hazard and the energy associated with it. Scales like the Richter or Mercalli intensity for earthquakes and the Volcanic explosivity index.

Frequency

Refers to how often an event is likely to occur

Relationship between Magnitude and Frequency

Generally inverse. the larger the magnitude the less frequent the event.

Duration

refers to the length of time the events lasts

extent

refers to the size of the region affected by the event.

Spatial Predictability

Refers to where hazards are located or centered and to some extent whether or not the hazard can be predicted (we know how tornados work so we can forecast them relatively accurately)

Speed of Onset

refers to the speed at which the peak of the hazard arises; may be rapid, moderate or low. Related to how much warning can be given to a population.

Geologic History of a Region. Why Important?

It helps in evaluating risk, examine maps, aerial photographs, satellite images, and geologic record can all help in determining if an area is at risk.

Event Profiles

A way to compare different natural hazards and the physical processes or attributes that they share. Based on Magnitude, Speed of onset, duration, areal extent, spatial predictability, and frequency.

Primary effects

Occur as a result of the natural process itself (building collapse due to an earthquake)

Secondary effects

Occur only because a primary effect has caused them (fire ignited due to house collapsing after earthquake)

Tertiary Effects

Long-term effects caused by an event (Cholera Epidemic due to poor water quality weeks after an earthquake)

Types of Vulnerability

Physical, Social, structural, Economic, cultural, Institutional

Physical Vulnerability

People who live in close proximity to hazard-prone regions are more exposed.

Social Vulnerability

Varying experiences in recovery from disaster due to differences in available resources and access to aid.

Structural Vulnerability

Integrity of the Built environment (in particular critical Infrastructure)

Economic Vulnerability

Variation in ability to respond to hazards based on differing economic systems. Capacity to respond/prepare for emergency (warning systems, first aid, emergency housing)

cultural vulnerability

Examines the roles that customs, beliefs, values, social organization, and knowledge play in societies policies and behaviour.

Institutional Vulnerability

refers to the capacity of the governing system to protect society from hazards

Disaster Management

Includes public policies, strategies, and practices with the aim of preventing, managing and reducing the impact of a disaster, including preparedness and response.

preparedness

planning and facilitating an effective response to a hazard event (warning systems, emergency preparedness)

Response

Actions taken immediately before, during and after a hazard event to protect people and property ( search and rescue, emergency relief)

Anticipatory Mitigation

Pre-event planning like land use, insurance, evacuation, personal preparedness, artificial control of natural processes, and building codes.

reactive mitigation

post-event reaction, like homeless shelters, emergency supplies, search and rescue efforts, firefighting, clean-up, and building code improvements.

What does most of the world focus on in the case of hazards

Post-event response and recovery methods. Though a shift is being made to focus on pro-active responses. Like in the case of the red river flooding in Canada, with floodways being built before flooding occurs in winnipeg.

Phases of recovery from a disaster

Emergency, restoration, Reconstruction I (meaning rebuilding) and reconstruction II ( major construction, leading to improvement and development). The last two extend to multiple years after the initial event.

Prediction

A statement of probability, that a precise event will occur based on scientific observation

Forecasting

Identifying the conditions by which a particular event may occur ( range of probability for an event)

Warning

A statement of high probability that a hazardous event will occur