NATURAL HAZARDS Flashcards
What is a natural hazard?
Extreme natural events that can cause loss to life , extreme damage to property and disrupt human activities
What are climate condition?
The usual type of weather that occurs in an area
What is tectonic activity?
Movements of the earth’s crust such as an earthquake or volcano
What is a tectonic hazard?
A hazard created when the earth’s crust moves
What is a climate hazard?
Hazards concerning the weather for example : heavy rainfall can lead to flooding
Name some tectonic hazards
Landslides
Volcano eruptions
Earthquakes
Tsunami
Avalanches
Name a few climate hazards
Flooding
Tornado
Tropical storms (Hurricane)
Drought
What is a natural disaster
A natural hazard that has actually happened
What is an extreme natural event?
Extreme events which do not pose a threat to human activity
What are the 2 types of natural hazards?
Geological
Meteororological
What is a geological hazard
Caused by land and tectonic processes
What is a meteorological hazard?
Caused by weather and climate
What are primary effects of natural disaster?
Immediate impacts
E.g:
Buildings and roads collapsing
People injured or killed
Crops damaged
Water supply affected
Electricity and pipe lines damaged
What are secondary effects of natural disasters?
Later impacts, as a result of the primary effects
E.g:
Earthquakes can trigger tsunamis
Aid can’t get through to help people due to blocked roads
Shortage of clean water
Food shortages
Unemployment
Name some immediate responses to natural disasters
Evacuate people
Treat and rescue injured
Recover dead bodies
Provide generators for temporary source of electricity
Provide food, drink and shelter
Charities may send aid workers, supplies or money donations
Name some long term responses
Repairing buildings, roads, houses, bridges, railways
Rehouse people
Reconnect Brocken electricity lines, water and gas
Improve evacuation plans
Improve building regulations
How many tectonic plates are there?
7
What does the crust float on
Mantle
Name two types of crust
Oceanic
Continental
Describe the mantle
Thick hot layer with the consistency of Jam
about 5000°C Near the coal
About 1300°C just below the cost
Lava
Describe the outer core
Liquid layer
Made of liquid iron
Describe the inner core
Solid layer
Made from iron
Temperature of 5500°C
How thick is oceanic crust
5 km thick
How thick is continental crust
35 to 75 km thick
Describe continental crust
older
Lighter
Permanent, cannot be destroyed
Describe oceanic crust
Younger
Heavier
Constantly been destroyed and replaced
How many houses were destroyed After the Nepal earthquake
500,000 homes destroyed
When was the Nepal earthquake
25th of April 2015
How long did the Nepal earthquake last
Two minutes
How did the Nepal earthquake affect Everest
Huge avalanche, like an ice tsunami
How did the Nepal earthquake affect long tang Valley
Landslides destroy everything, like a tsunami of rocks boulders and mud
Buildings flattened, villages are varied
Why did the Nepal earthquake happen
Nepal is on the edge of a plate boundary
The plates got stuck
The pressure built up to 7 times as much force as a nuclear bomb,
When the plates slipped, it caused an earthquake

Why do tectonic plates move
Convection currents in the mantle
How does convection currents in the mantle work
The rising limb = heated rock rises as it is less dense
At the top = Semi molten rock spreads out and carries the above plate with it
Falling Limb = Cools and sinks back down to be reheated
The heat source =. The core is radioactive decay in it causes heat
What do you get at destructive plate boundaries
Violent earthquakes
Violent volcanoes
What do you get at collision Plate boundaries
Violent earthquakes
No volcanoes
What do you get at constructive plate boundaries
Less violent earthquakes
Gentle volcanos
What do you get at Conservative plate boundaries
Violent earthquakes
No volcanoes
Describe a destructive plate Boundry
Oceanic crust meets continental crust, heavier oceanic crust sinks into mantle and is destroyed
Describe a constructive plate boundary
Two oceanic plates move apart
A gap in the mantle is created and lava escapes creating new crust
Describe collision plate boundaries
Two continental plates meet
Neither can sink and be destroyed, so they buckle upwards and form fold mountains
Describe Conservative plate boundaries
Two plates slide past each other
They get stuck and pressure is built
When released this causes an earthquake
What plate boundaries are volcanoes made
Destructive
Constructive
What plate boundaries are earthquakes Caused
All
Destructive, collision and Conservative all have a violent earthquakes
Constructive have less less violent earthquakes
What magnitude was the Nepal earthquake
7.8
What type of plate boundary is Nepal on
Destructive
How many people didn’t have access to clean water or sanitation after the Nepal earthquake
2 million people
How many people died in an avalanche from Mount Everest caused by an earthquake from the Nepal
18
What disease out broke due to lack of clean water caused by the netball earthquake
Typhus, killing at least 13 people
What is the epicentre. Of an earthquake
The point on the earths surface directly above the focus, this is where the maximum damage is caused
What is the focus of an earthquake
The start of the earthquake
What is damage decrease ( earthquake)
Damage decreases with distance from the epicentre
What are earthquake seismic waves
Spread outwards, the strength decreases with the distance from the focus, waves caused by earthquakes
Vibrations
How do we measure earthquakes nowadays
Richter scale, a 12 point scale that describes the magnitude or power of an earthquake as measured by a seismometer
If a seismometer records levels of five and over, it is classed as an earthquake
What is a seismometer
An instrument that responds to ground noises and shaking, caused by earthquakes and volcanic eruptions and explosions
A suspended pen wobbles with the movement of the ground drawing a seismograph onto a piece of paper that’s revolving, if it’s an earthquake we will see mountain shaped lines
What does a seismometer create
A seismograph
What are the 3P’s That help people to live with earthquakes
Predict
Protect
Prepare
How do we predict earthquakes
Observing animal behaviour
Observing seismographs – they pick up minor tremors before the main event
TiltMeter – checks for any movement in the rocks
How do we protect against earthquakes in HICs
Steel frames which can sway
Automatic window shutters which prevent falling glass
Foundations sunk into bedrock, avoiding Clay
Rubber shock absorbers to absorb earth tremors
Birdcage interlocking steel frame around buildings
How can we protect against earthquakes in LICs
Walls made of mud and straw pact between wooden slats
Lightweight thatched roof
Crossed brass wood or bamboo frame
Concrete ring ties the walls to the foundations
Simple steel rod foundations
How can you Preoare for earthquakes?
Education, know what to look for
Plan evacuation routes
Emergency supplies
Practised drills
