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types of hazardous enviroments - Coggle Diagram
types of hazardous enviroments
volcanos and earthquakes
earthquakes
earthquakes are vibrations caused by earth movements at tectonic boundaries and at major fault lines (cracks in earth's surface)
Earthquakes occur at all plate margins, as well as along fault lines that spread out from the main fault.
Over time, stress builds up at these plate margins as plates rarely move continually. When this is suddenly overcome the plate moves, causing the rocks to fracture and creating an earthquake.
The longer a fault remains locked, the more stress builds up and
the greater the earthquake
parts of an earthquake
empicenter
the pint directly above of the focus, on top of the earth's crust
seismic waves
waves that are released by the energy of the earthquake, this start at the focus
focus
the point were the rock moves
earthquake waves
body waves
p waves
faster and travle through solids and liquids, they are the first to arrive
s waves
slower and can only travel through solids
https://cdn1.byjus.com/wp-content/uploads/2020/07/P-Wave.png
surface waves
love waves
they produce entirely horizontal motion. The amplitude is largest at the surface and get smaller with greater depth.
rayleigh waves
they move the surface of the earth around in a circle, they move horizontaly and verticly. They cause the most damage
measuring earthquakes
scales to measure earthquakes
richter scale
It is a logarithmic ( 10 to the power of the number it is in the scale) the power is measured in kg of dynamite. It is the most factual scale as it relies on non bias facts. A magnitude 5 earthquake will cause structural damage. The scale has no limit
mercalli scale
The Mercalli scale measures how much damage is caused by the earthquake based on observations. It is subjective and based on people’s opinions. It is measured on a scale between 1 and 12.
eartjquakes are measured useing a seismograph
things that affect the damage an earthquake does
depth of the focus
magnitude
type of rock
distance from the epicenter
time of the day
building design
population
volcanos
A volcano is an opening or vent in the earth’s surface through which molten material erupts and solidifies as lava.
there are 3 types of volcanos
composite volcano
they look like a steep hill with explosive eruptions of lava and rock
cinder cone volcano
This type of volcanos are low, with sloping sides and frequent but gentle eruptions
shield volcano
these volcanos are made out of leyers of lava and ash. They have eruptions of hot steam, lava, ash and rock. This volcanoes are normally flater than other type of volcanos
there are 3 types of volcanos status
extinc
unlike to erupt, volcanic activity finished
dormant
eruptd in the past 2000 years
active
erupted recently and likely tto erupt again
parts of a volcano
crater
secondary vent
bomb
main vent
ash cloud
magma chamber
lava flow
https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1920/https://cdn.savemyexams.com/uploads/2022/10/features-of-a-volcano.png
why would people want to live near them.
volcanic soils are fertil
sulphur and other rare minerals can be mined near volcanoes makeing living near them have a good source of money
the volcano can bring lots of turism
geothermal energy
examples of volcanos
mt st helens
type of volcano eruptions
explosive
Explosive eruptions occur where cooler, more viscous magmas reach the surface. Dissolved gases cannot escape as easily, so pressure may build up until gas explosions blast rock and lava fragments into the air. This will cause clouds of hot debris and ash. An example of this is the eruption of mt st helens.
non explosive
they are the most common eruptions, These eruptions produce relatively calm flows of lava in huge amounts
how do you measure the strength of a volcano
The Volcanic Explosivity Index (VEI) is a measure of the explosiveness of volcanic eruptions.
The index is based on a scale of 1 to 8, 1 being very small, and 8 being hugeand very rare. The level of an eruption is based upon:
Volume of products
Eruption cloud height
Qualitative observations
the VEI is a tenfold scale ( each number it increases it gets multiplied by 10
this are natural hazards caused by tectonic movement
tsunamis
how are they caused
An earthquake or volcanic eruption happens,
the rock is pushed upwards shifting the ocean and causing a massive wave
the waves are small but travle at great speeds
as waves get to shallower waters they slow down
the back of the wave moves faster than the front, so the back rises creating a massive wave
before the tsunami hits the water in the shore retreats a long distance
the wave hits and destroys the shore
effects
Many people dead or missing.
Millions left homeless as their homes destroyed.
Businesses destroyed.
Farmland lost.
Lack of clean water and food.
High chance of catching waterborne diseases.
Water pollution.
Fishing boats destroyed, so fishermen lost income.
Hotels damaged.
Roads and bridges damaged.
Loss of natural habitats.
cyclones, typhoones and hurricanes
cyclones are called different ways in different places
typhoons
on the northwest pacific (japan, papua new ginie and nort east of australia
cyclones
the south of the pacific and the Indian ocean
hurricanes
coast of North America
How do they form?
this events happen between the tropic of cancer and the tropic of capricorn. They normally happen on waters of 27 degrees
The intense heat makes the hot air rise.This air gets filled up by the cold air. As the hot air rises it leaves a gap
2.This gap then gets filled by a spiraling motion (coriolis effect) from surrounding air.
3.The hot air then cools and condensates producing heavy rain.
Then the cold air sinks and gets replaced with more hot air.
When the cyclone leaves the area where the water is hot or reaches land the cyclone stops as it cannot be fed more hot air stopping the cycle
6The rapidly spinning, rising air creates high pressure in the centre of the cyclone, the eye.
Cyclones are large, violent storms that involve very strong winds and rain. They usually cover an area up to 160 square km. Winds of up to 250 km/h
how are they measured
they are measured in the saffin-simpson hurricane wind scale
3
extensive
4
extream
2
moderate
5
catastrophic
1
minimal
characteristics
Tropical cyclones follow the direction of prevailing winds and ocean currents.
The further it travels over the sea, the more energy (heat and moisture) it gathers from contact with warm ocean waters, increasing its strength.
The average duration is 10 days, but the biggest can last for up to four weeks.
damages they cause
torrental rain
inland flooding, landslides, mudslides
storm surges
The wind pick up water and pushes it towards the shore
2.Water gets pushed water inland faster than the waves can be drained off.
the flood causes effects to the costal areas as
deforming the shore line
affecting the ground beneath some buildings collapsing the buildings
floating debris affecting the costal area
strong winds
destroy trees, crops, buildings, transport links, power supplies, communications
stages of a cyclone
4.Wind and rain suddenly cease
eye of the storm, Bright sky and sun appear
3.Winds become very strong as core approaches. Air pressure drops rapidly. Intense thunderstorms; torrential rain
6.Strong winds return, but from a different direction. Thunderstorms resume. Air pressure starts to rise steeply
2.Air pressure drops at an increasing rate. Wind gets stronger; rain showers
7.Air pressure continues to rise. Weather calms down as cyclone moves away
1.Weather is usually clear, warm and wind blows from unusual direction. Sky is overcast with cirrostratus clouds
primary and secondary impacts
primary impact
the direct impacts of the natural hazard
secondary impact
the indirect effects causes by the primary impacts, after the main event - in the coming hours, days and weeks.