Natural Hazards Flashcards
What is a natural hazard?
An unexpected or uncontrollable natural event that threatens people
What are the four types of natural hazards?
Tectonic, Atmospheric, Geomorphological, Biological
Give the three types of tectonic hazards
Earthquakes, Tsunamis, Volcanoes
Give the two types of atmospheric hazards
Droughts and Tropical Storms
Give the five types of geomorphological hazards
Avalanches, Sinkholes, Sandstorms, Floods, Landslides
Give one type of biological hazard
Forest Fires
What is the structure of the earth?
Inner core, Outer core, Mantle, Crust
What are the two types of crust?
Oceanic and Continental crust, oceanic crust is thinner, more dense and made of basalt whereas continental crust is thicker, less dense and made of granite.
Plate margin
Where two tectonic plates meet, also called a plate boundary
What is the name of the current in the mantle?
Convection currents
Where are volcanoes located?
Volcanoes are mostly located linearly along tectonic plate boundaries
Why do tectonic plates move?
Slab pull and convection currents
What is the name for one plate sinking under another
Subduction
Name the three types of plate margins
Constructive, Destructive, Conservative
Active volcano
Has erupted within the past 2000 years
Dormant volcano
Not erupted for at least 2000 years but has the potential to erupt again
Extinct volcano
Will not erupt again
What type of volcano forms at a constructive plate boundary?
A shield volcano
What type of volcano forms at a destructive plate boundary?
A composite volcano
What is an earthquake
The shaking of the earth’s surface
How are earthquakes measured?
Using the Richter Scale, it is logarithmic meaning each point is 10 times more destructive than the previous point
What is the focus?
The point inside the earth where the earthquake started
What is the epicentre?
The location directly above the focus
What four things reduce the risk of natural hazards?
Monitoring, prediction, protection and planning
Monitoring
Using scientific equipment to detect warning signs of events. Not so useful for earthquakes. There may be some signs an earthquake is imminent like tremors or foreshocks but often there are tremors but no earthquake.
Prediction
Using historical evidence and monitoring, scientists can make predictions about where and when a tectonic hazard may happen but it is impossible to predict an earthquake.
Protection
Designing buildings that will withstand tectonic hazards.
Planning
Identifying and avoiding places most at risk, making sure people are prepared for a tectonic hazard.
Tropical storms
Large areas of low pressure or extreme depressions that bring high winds and torrential rain, as they move they rotate, they have winds above 74mph
Low pressure
A point of rising air and rainfall
High pressure
A point of falling air and dry weather
Where do tropical storms occur?
Over 27 degree seas, between 5 and 30 degrees north or south of the equator in the tropics of Cancer and Capricorn.
Low wind shear
Winds at all levels of the atmosphere blowing in the same direction
Give three names for a tropical storm
Hurricane, Cyclone, Typhoon
What are towering bands of cloud called?
Cumulonimbus clouds
What is the name given to the wind that rushes in from areas of high pressure?
Trade winds
What is in the middle of a storm?
The eye
Why do tropical storms spin?
The Coriolis effect
How does climate change impact tropical storms?
Frequency, Intensity and Distribution
What was the name of the typhoon that struck the Philippines?
Typhoon Haiyan
