Topic 1 - Introduction Flashcards
What is a Hazard?
A naturally occurring or human induced process, or event, with the potential to create loss.
Ex.) Wildfire
What is Risk?
The probability of a hazard occurring and creating loss
Ex.) Probability of a wildfire occurring and creating loss
What is a Disaster?
When large numbers of people are killed, injured or affected in some way by a hazard event.
Ex.) Actual wildfire that causes significant losses
UNISDR definition of Disaster
“A serious disruption of the functioning of a community or a society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources”
A Disaster occurs when: (Canadian disaster database)
o 10 or more people are killed
o 100 or more people affected/injured/infected/evacuated or homeless
o An appeal for national/international assistance
o Historical significance
o Significant damage/interruption of normal processes such that the community affected cannot recover on its own.
Magnitude: Richter Scale
o Logarithmic scale
o Describes the total amount of energy released
• Energy released by the earthquake in the form of seismic waves
o Increase in number by 1 = increase in energy release by 32
• Measured at the epicentre
Magnitude: Moment Magnitude Scale
o Rigidity of the rocks near the focus of the earquake;
o Movement or slippage along the fault; and
o Estimate of the Area ruptured along a fault line.
• Most commonly used scale nowadays
• The moment magnitude scale (abbreviated as MMS; denoted as MW or M) is used by seismologists to measure the size of earthquakes in terms of the energy released.
3 - very minor
8+ - happens once a year
Modified Mercalli Intensity Scale
- The Modified Mercalli Intensity value assigned to a specific site after an earthquake has a more meaningful measure of severity to the nonscientist than the magnitude because intensity refers to the effects actually experienced at that place.
- Based on observed factors, not measuring
- Higher Roman Numeral is worse up to XII
Intensity and Shake Maps
- Did you feel the earthquake - fill out questionaire
- Allows to get information more quickly, but still takes time.
- Shows on a map, how felt the magnitude of the earthquake
Enhanced Fujita Tornado Scale
- Old Scale used to measure severity of tornadoes
- Based off of wind speeds
- 0 is lower, and 5 is highest speeds
U.S. Saffir Simpson Hurricane Wind Scale
- Newer scale to measure tornadoes
- Based on windspeeds, but also tells you the qualitative information as well
- Category 3,4, and 5 are major
Why are scales important?
- How concerned should people be? Should they donate?
- What information comes to emergency services
- Predictions can help people make deicisions in advance, and prepare for such a disaster
What is a 1 in 100 Year Flood?
A one-hundred-year flood is a flood event that has a 1% probability of occurring in any given year
Misconception because people interpret this as once every 100 years
1/50 year flood = 2% chance every year
- 1 in 100 year levels can change
How long does a Hazard event exist for? (Duration)
- can range from several minutes, to days, to years
- Earthquakes, tornadoes, avalanches, land slides tend to be shorter duration.
- Wildfire, in land floodings, hot and cold flashes, have longer durations
- Droughts have very long durations (years)
Rate (or speed) of Onset
- How does the hazard turn out with time?
Ex.) Hurricane Catrina, over the course of 6 days
