Natural Hazards Flashcards
List the three energy sources for natural phenomena and what they lead to.
Earth’s internal heat: convection in mantle; leads to earthquakes, volcanic eruptions.
Solar energy: sun warms earth, circulation of atmosphere, oceans, evaporation determine climate; related to violent storms, floods, wildfires.
Gravitational attraction: attraction of materials towards centre of earth, rocks/soil/snow/water move downslope; attracts objects from space.
Define a natural hazard and how it relates to probabilities.
Any natural process that threatens human life or property.
Probability that a specific damaging event will happen in a given time period.
True/false: the hazard is the process itself.
False.
What is a natural disaster?
Extreme events triggered by destructive forces occurring in nature, cause significant disruption to society.
Natural disasters are usually rapid (seconds to weeks) and have limited _____ extent.
Areal.
This event is considered to be more massive and affects a larger number of people or more infrastructure than a natural disaster. What is it?
Catastrophe.
According to the Geologic Survey of Canada, there are two types of hazard. Define both.
Catastrophic Hazards: sudden onset, occur without much warning, loss of life and damage to property.
Hazardous Conditions: occur slowly, property damage and long term health issues.
List the four hazardous conditions posed by climate change.
Sea level rise: flooding (3mm/year).
Geochemical: radiation, elements.
Permafrost thawing: increased methane.
Natural gas hydrates: frozen methane.
List the four types of catastrophic hazards in Canada.
Geological: volcanoes, earthquakes, tsunamis, geomagnetism.
Climatological: hurricanes, tornadoes, blizzards, avalanches.
Multiple conditions: floods, landslides.
Extraterrestrial: impacts, solar storms.
What is risk? How is it calculated?
Function of the hazard plus exposure.
Risk = Hazard Probability x Vulnerability.
What is acceptable risk?
Level of risk tolerated before action is needed to reduce exposure to the process.
What is a hazard assessment? What does it NOT do?
Evaluation of possibility and/or probability that threatening process can or will occur.
Does not quantify risk.
What is risk analysis?
Evaluation of the probability of a hazardous process and its possible consequences.
What are the three deadliest hazards?
Flooding.
Earthquake-tsunami.
Hurricanes.
With disasters, what can you expect in more developed areas with regard to damage?
More costs.
Canada has a relatively low risk for a developed country. What are four reasons that explain this?
Low frequency of earthquakes.
Low population density.
Less vulnerable infrastructure, good building codes.
Some emergency management.
What are natural processes?
The ways in which events affect the Earth’s surface.
What is mitigation?
Efforts to prepare for disasters, minimize harmful affects. Actions taken to reduce or eliminate long-term risk to human life and property from natural hazards.
Magnitude is the amount of energy increased. How is it calculated?
M = 1/frequency
What is a recurrence interval and what is important to note about them?
Average time between the occurrence of two events of given magnitude, historical record.
Individual events inherently unpredictable.
The impact of an event is a function of what?
Magnitude and frequency.
What is a prediction?
Statement of probability that an event will occur, based on scientific observation.
What is a forecast? How does it relate to weather and earthquakes?
Public announcement that a hazardous event likely to occur during specific period, commonly with statement of probability.
Weather-related: specific short-term predictions.
Earthquake: less precise, long-term probability and not specific.
Forecasts are based on what two things?
Data and models.
What is the difference between a prediction and a forecast?
Prediction specifies whether disaster will/won’t occur at a given place, during a given time, with a given magnitude range. Forecast pertains to probability.
What is a hindcast? What does it help define?
Means of testing models and evaluation uncertainty using data from past events.
Helps define magnitude limits, boundary conditions.
In hindcasts, the longer a record is, the better. How long should weather hazard records be? Seismic hazard records?
Weather hazards: 40+ years.
Seismic: hundreds of thousands of years.
Forecasting and warning can be attempted if what three elements are met?
Location of hazard.
Probability that an event of a given magnitude will occur.
Identifying any precursor event.
