Natural hazards Flashcards
What are some concerns that geographers face with natural hazards
How, where occur plus what causes it. Loss of life. Human geographers study white people live at places with hazards
What are not natural hazards unless it affects people
Fire is natural and ecosystems and earthquakes happen
What are the different types of natural hazards
Tectonic hazard, gravitational hazard, climatic hazard.
What is tectonic hazard
Shifting movement of oceanic and continental plates which makes it into earthquake, volcanos and tsunami’s
What is gravitational hazard
Rock, snow, ice, debris flow down a slope, rockslides, landslides, mudslides avalanches, debris slides and debris torrents; tsunami
What is climatic hazard
Unusual and extreme weather conditions – droughts, fire, floods, lightning, hail, ice storms, wind (hurricanes, typhoons, tornadoes); storm surge (high winds and tides)
Reasons why people stay in places with natural hazards
Flat lands and availability of water, mountain regions help with forestry, mining and fishing & transportation. Sense of place. People know how to control harmful effects of natural hazards. People adapt and have connection to place they live. Government laws that make people feel safe. Earthquake proofing the house or building.
Risk= probability of occurrence x magnitude of impact (consequence)
The equation
What do human responses to living with natural hazards Include
Institutional – laws and regulations to restrict people from building in certain areas like steep slopes, floodplains etc. they earthquake proof, flood proof, fire proofing houses. Emergency response plans
physical works Dash Dyking, scaling of rock slopes, contaminate barriers etc.
Resettlement Dash if hazardous people have to permanently move
Behavior/psychological – personal decisions. How much hazard can you handle until it affects your mental health
What are five ways of measuring extreme Geophysical effects
Magnitude, frequency, speed of onset, duration and spatial pattern
What is magnitude
Measures intensity of the event. Measuring intensity or size of an earthquake
What is frequency
Measures how often an event occurs in any location. Related to season Dash fires in summer, flooding in spring, flash floods in winter.
What is speed of onset
Refers to how rapidly the event occurs and how much warning is likely. Earthquakes and avalanches have until the last warning whereas floods usually have more warning
Duration
How long events last
What is spatial pattern
Repeated events or patterns over time that can be made and used as a basis for prediction and assessment of risk
What are two floods
Snowmelt floods & flash flood
How are snowmelt floods caused
Prolong high temperature causing fairly rapid snowmelt
How are flash floods caused
High rainfall events over fairly short period of time
When did the large flood happen
1894 in Mission
What’s the worst natural disaster
Avalanches because they caused greatest loss of life in British Columbia
Factors Contributing to avalanches
Type of snow Dash hard pellets do not bind together
Rate of snowfall - accumulates fast can lead to unstable conditions. Snow is loose hasn’t had time to pat down
Terrain slope - danger zone is 30 to 60°. Steeper more snow coming down
Temperature change – of 6°C or greater per hour can create unstable condition
When do debris flows and Torrents occur
In coastal locations in steep mountain streams or valleys. They result from intense or prolonged rainfall events.
How to wildfires occur
Natural forest and grassland wildfires usually caused by lightning.
Are wildfires important for the ecosystem and why
Yes and they put carbon in soil and enable new growth of trees and shrubs. Some trees require heat to release their seeds.
