🌋 Natural Hazards Flashcards
Natural hazard
A natural event that threatens people or has the potential to cause damage, destruction and death
Tectonic hazards
Earths crust + plate boundaries
Earthquake
Tsunami
Volcanic eruption
Atmospheric hazards
Air
Tropical storms
Tornado
Global warming
Fog
Frost
Wind
Rain
Hail
Snow
Thunder and lightening
Freezing rain
Geomorphological hazards
On land
Erosion
El Niño
Coastal/river flooding
Mass movement
Salinisation
Sea ice and ice burgs
Forest and bush fires
Glacier surge/advance
Biological hazards
Living things
Animal and plant invasions eg. Locust swarms
Server disease epidemic in humans/plants
Forest and bush fires
Why are some hazards difficult to categorise?
Fall into more than one category
Tectonic hazards around the world ..
are:
unevenly distributed
found at plate boundaries
4 layers of the earth
Crust
Mantle
Inner core
Outer core
Crust
Outer layer
Up to 75km thick
Solid
Continental and oceanic
Split into plates
Mantle
Middle layer
Up to 2800km thick
Upper part = lithosphere and is rigid
Lower part is largest layer = asthenosphere and semi molten rock half liquid half solid and it moves
Inner core
Innermost part
Composed of iron and nickel
Solid
5000oC
Hottest part of the earth
Pressure
Outer core
Central part of the earth
Outer part of core has liquid properties
Liquid at 3000oC
Oceanic crust
Basalt
6-10km relatively thin
Underneath oceans
>200 million years old (relatively new)
Very dense
Renewable
Destroyable
Continental crust
Various eg. Granite
70km very thick
On the land
1500 million years old
Less dense
Non renewable
Cannot be destroyed
Plate boundary / margin
Places where 2 plates meet
What cause the tectonic plates to move
Convection currents
Describe convection current (5)
Heat source radioactive decay in earths core
Heated rock in mantle rises as it is less dense
Semi molten rock spreads our carrying the plate above with it
Direction of plate move,ent = direction of convection current (constructively, destructively…etc)
Cools down and sinks to be reheated as it had lost its heat energy
4 plate boundary types
Collision (—><—)
Destructive (—><—)
Constructive (<——>)
Conservative (<===>)
Constructive
Moving away from
Gap for magma to rise, and cools down to form solid rock
Volcanos form but don’t erupt with force as it can escape easily
Earth quakes
Mid Atlantic ridge
Destructive
Dense oceanic plate subducts below less densest continental plate
As plate sinks it is destroyed due to pressure and it melts closer to the mantle
Stores magma in subduction zone
Erupts into a volcano as magma is forced o rise to the surface
Ocean trench
Conservative
Two plates slide past each other along a fault line
Sna address fault
Friction causes Often stuck which builds pressure and erupts into an earthquake
No volcanoes
Same or different direction but differ g speeds
Collision
32 plates of similar density move together
Cause material between them to fold and buckle and rise up for in fold mountains
Himalayas
No volcanoes
Earthquakes are caused by …
Caused by earth movements at plate margins
Earthquakes at
All plate margins
Focus
Point where the waves started in the crust
Epicentre
Point directly above the focus on the earths surface
Seismic waves
The shockwaves are seismic waves generated by an earthquake that pass through the earths crust
Richter scale measured
Amount of energy released (magnitude) using a seismometer
Richter scale measured
Amount of energy released (magnitude) using a seismometer
Richter scale is from
1-10 each levels 10 times stronger
Mercalli scale measures
Effects of an earthquake
Damage done
Subjective
Mercalli scale from
1-12
Frequency
How often an earthquake occurs
Risks of living in a hazardous area
Death
Property damage
Loss of job
Loss of belongings
Injuries
Unemployment
Rewards of living in a hazardous area
Volcano:
Minerals form soil
Geothermal energy
Fertile soils
Tourism
Coast:
Flat land
Time to evacuate due to successful procedure
Good climate
Good transport links
All:
Family
Jobs
Resources
Livelihoods
Why do people live in hazardous areas?
Lack of knowledge
Lack of funds to move
Language barrier
Confidence in defences
Can’t predict it
Predict
Making an educated guess about a future event
Allows time to prepare an protect
Eg, animal senses, tilt meters, foreshock metres
Protect
Safe and secure
Earthquake houses springy foundations, good exits, sliding foundations, steel frames, rubber shock absorbers
Prepare
Plan in place, earthquake = emergency plan
Drop, cover hold on
Building codes
Emergency kits
Construct shelters
Turn off gas immediately
Earthquake practices
What is atmospheric circulation?
The general movements of air around the Earth due to pressure and temperature
Adaptation
Is responding to climate change by coming up with ways to live and cope with the effects of
What is Carbon Capture and Storage?
The process of capturing carbon dioxide that would normally be emitted into the atmosphere and storing it underground in reservoirs
