Unit 11 – Earthquakes and Volcanoes
● Happens in Lithosphere
- Natural hazard → threatens to cause great damage or loss of life
- Natural Disaster → many life loses and threats
● Tonga volcano eruption ~ largest explosive of 21st century
Pangea
● Wegener's theory (1912) - Continental drift
● Argued that millions of years ago the continents were joined together
into one supercontinent - Pangea
● Evidence - similar animal fossils and rock types found on different
continents
● Britannica "Pangea"
Ocean Floor
● Mid-ocean ridges (mountain ridges)
● Ocean trenches (long, narrow, deep depressions near the edges of
continents)
Earth's Structure
● Crust / Lithosphere (50-200 km in thickness)
● Mantle (Magma=molten rock)
● Core: Outer Core (liquid)
● Core: Inner Core (solid, made of iron and nickel)
Earth's core temperature = Sun’s temperature
Tectonic Boundaries - where 2 plate meets
Types of Boundaries: 3
● Destructive (Convergent)
➔ Pulls away from each other
➔ Mostly under the sea
➔ Create volcanoes and Earthquakes (weak)
● Constructive (Divergent) - only with oceanic and continental
➔
Subduction
★
Oceanic plate subducts under the continental plate
★
Create powerful volcanic eruptions due to pressure
➔
Towards each other
➔ Volcanoes and Earthquakes
➔
➔
➔
➔
Collision Boundaries (continental and continental
Towards each other
Create fold mountains
Makes earthquakes
● Conservative (Transform)
➔
Side by Side, in the opposite direction
Why do tectonic plates move?
Theory 1 - Earth's internal heat creates convection currents in the mantle,
transferring heat, which rises and cools back down in a circular motion, moving
plates above.
Theory 2 - The heavy weight of the plate going down pulls the whole plate
along and down, like a coat falling off a table (Slab pull)
Earthquakes start - Focus
Foreshocks (before) --> Mainshock (during) --> Aftershocks (after)
Faults/Fault Lines = Plate Boundaries
Shocks last for weeks.
High-income countries
❖ Strict building codes --> safer buildings
❖ Make earthquake-resistant buildings
❖ Urbanization controlled
Volcanoes
When it erupts - lava, dust, stone, gas came
out
Magma - a mixture or hot, molten rock
Lava - when magma erupt out of the
volcano
An opening in the earth's crust
(lithosphere) where magma and gasses from
inside the Earth escape onto the surface.
Types of Volcanoes
●
●
Composite/Stratovolcano
➔ Steep-sided, cone-shaped, tall volcanoes, formed from layers of
sticky lava that doesn't flow far
Shield Volcanoes
➔ Gentle slopes, wider area, formed from runny lava that spreads far.
Gasses escape easily
Why do people live near volcanoes?
●
Fertile soil good for agriculture
●
Minerals
●
Geothermal energy for electricity
●
Tourism
Prediction - monitor volcanoes. Planning evacuation plans, and warning systems.
Preparation involves educating people.
Volcanologists - predict
Unit 12 – Africa
●
●
●
●
Africa is relatively flatter than other continents or regions.
Sahara desert - the world's largest sand desert
Niles River - longest - through 10 countries
Half of the diamonds are produced in Africa, 22% of gold, and 30% of the
remaining resources
● Rich in oil and gas
● Africa's natural resources are not evenly distributed across the continent concentrated in a few countries.
Africa’s Climate and Biomes
Biomes in Africa - Desert, Grassland, Rainforest, Deciduous woodland, Tropical
Rainforest
Biome = A large geographic area with similar environments, plants, and animals
Savanna Biome - Grassland with scattered trees, wet & dry seasons, wildlife
migration
Desert Biome - driest biome, rarely ever get rainfalls, extreme temperature
Tropical Rainforest Biome(Congo Basin) - hot, moist biome where it rains all year
long, with many tall trees
Deciduous Forest Biome - rich in moisture, grows in one of the suitable seasons
Suggestion to watch - Intertropical Convergence Zone (ITCZ)=A region near the
Equator with high rainfall (low pressure) due to strong sunlight
ITCZ and Trade Winds
The Sahel Region = southern edge of the Sahara Desert
Overgraze = too much grazing by livestock (animals)
Clearing vegetation from lands (deforestation) to farm, to build shelter, to get
firewood, to feed livestock leads to :
Soil exposed to wind and water → Soil Erosion
Desertification forms (Desert Spreading) from → Soil Erosion & Drought
Human Geography of Africa
● French speakers in Africa - Francophone
Triangle trading Route
Between the 1600s to 1800s, 12-15 million Africans were sold into slavery in
exchange for goods
Imperial nations were keen to exploit the rich natural resources of Africa and cheap
labor
The 'Scramble for Africa' in the 1880s - European countries raced to occupy the
continent seeking economic and strategic gains.
Berlin Conference 1884-1885 - creates new borders for Africa, the partition of
Africa confirmed
Video Suggestion: Berlin Conference
King Leopold II of Belgium, took control of the tropical rainforest in the Congo
Basin - 75 times larger than Belgium - the richest part of Africa
industrial Revolution drove up the demand for rubber → lead to the taking over
of rubber tree sap in tropical rainforest
Video Suggestion: History of Scramble for Africa
Estimated 10 million Congolese people died from abuses during King Leopold's
rule in Congo
What colonialism did to Africa
● Little attention was given to the education, health, and training for Africans
during colonial rule
● Territories were used as sources of raw materials for the benefit of the
colonial powers
● No allowance for continental development
Decolonization of Africa
● After World War 2
● Between the 1950s - 1960s (In 1960, 18 colonies became independent Congo, Madagascar, etc)
● By 1966, most of Africa independent
● British colonies first to gain independence (Ghana, Nigeria, etc), Portuguese
last
● Civil wars, neo-colonialism
For decades, the Democratic Republic of the Congo has seen one of the world’s
longest-running armed conflicts
Development
HDI - Human Development Index
HDI measures a country's achievement in three key dimensions:
● a long and healthy life
● Knowledge/Education
● a decent standard of living
Changes and Challenges for Africa
Africa - 2nd most populated country on earth
Africa has the fastest urbanization rate in the world.
Second most populated country in Africa (Over 100 million) / Landlocked country
/ Rapid urbanization
Landlocked Country - A country surrounded by land
Slums = informal (improvised) settlements
Slums lack infrastructure and are often unsafe
Social Housing - Residential buildings built by governments
- Affordable buildings to live in
Advantages of the Railway
● Easier access to the sea
● Reduce transportation time (weeks to days)
● Reduce transportation costs
● Easier to move goods (imports & exports)
● Manufacturing sector grows
● Economy grows
Trade between China & Africa
● China overtook the USA as Africa's largest trading partner in 2009
● 15% of Africa's exports, mainly natural resources, go to China
● China provides 21% of Africa's imports (machinery, transportation,
communications equipment, goods)
● China continues to fund the building of factories, roads, railways, ports,
airports, hospitals, schools, and stadiums (infrastructure)
● More than 1 million Chinese laborers and traders have moved to Africa in
the past decade
Belt and Road - the name of China’s multibillion-dollar initiative/investment in
infrastructures around the world
Unit 13 — Glaciers
Large masses of slowly moving ice (rivers of ice) made up of fallen snow
that gets compressed into ice along with rock, sediment over many
centuries
frozen seawater that floats on the ocean surface - Sea Ice
Extra large masses of glacier, also known as continental glaciers - Ice
Sheet
Pieces of a glacier broken off into water - Ice Bergs
type of glacier covers extra large area of land and is spread out - Ice sheet
Glacier move slowly downward → gravity
erode the landscape, creating different landforms
Glaciers form the largest reservoir of fresh water on our planet
As glacier melts, it provides running water (rivers, streams, lakes) to our
planet
1. Alpine Glaciers
- Form on mountainsides and move down slopes through
valleys
Where are glaciers found?
● Where average annual temperatures are near freezing point (0ºC)
● Large amounts of snowfall during winter months
● Temperatures throughout the year are not high enough to melt the
previous winter's build up of snow
Scientists who investigate glaciers all over the world - Geologists,
Glaciologist
Snow builds up (accumulates) over many years (at least 100 years) -->
Snow becomes compressed into ice --> Dense, hard ice forms and starts to
flow down-slope with its weight.
Accumulation (gained)
Ablation (melting)
Snout = the end of a glacier where water is released
Crevasse = a deep opening in a glacier
A period of time where global temperatures drop so significantly that
glaciers advance and encompass over one third of Earth's surface - Ice
Age
A glacial period is the colder period where glaciers advance (AKA Ice Age)
/ An interglacial is the warmer break in between two ice ages were glaciers
retreat
Pluck - to remove forcibly
Abrase - to rub off
1. Weathering
When melted snow enters cracks in rocks around and below glacier -->
water in rocks freezes and expands --> cracks get larger --> repeat -->
break rocks apart around and below glacier
2. Erosion
Rocks become frozen into the bottom and sides of the glacier. As the
glacier moves downhill it 'plucks' (rips off) the rocks frozen into the
glacier from the bedrock.
As the glacier moves downhill, rocks that have been frozen into
the base and sides of the glacier scrape the rock beneath like
sandpaper, leaving behind smooth, polished surfaces with
scratches in them.
3. Deposition/Erosion
As the glacier moves down it transports vast amounts of rock mixed with
ice. Any material (debris) carried by a glacier is called moraine. Any water
from melting ice feeds a river or lake.
Landforms by Glacial Erosion
● U-shaped valleys
● Hanging valleys/waterfalls
● Truncated spurs
● Misfit rivers
● Fjords
● Ribbon lakes
● Corries
A series of ridges overlapping each other (in V-shaped valleys/river valleys)
- Interlocking Spurs
glacier cuts through the interlocking spurs, leaving behind truncated spurs
in a U-shaped valley - Truncated Spurs
Smaller valleys above the new U-shaped valleys. Often, streams
fall from hanging valleys as waterfalls.
A large, narrow (long), thin lake occupying a
U-shaped valley after the ice melts - ribbon
lake
Small river usually flows in U shape valley
after the glacier melts - misfit river
After glacier melts, the sea fills the valley
floor (Fjord = a long strip of sea between
steep hills (inlet))
Fjords - Norwegian language
A corrie is a hollow (hole) found on the side of a mountain. This is
where a glacier forms.
Snow collects in a hollow on the side of a mountain, compacts into ice
→ Back wall of the corrie gets steeper due to freeze-thaw weathering
and plucking → The base of the corrie becomes deeper due to
abrasion → Corrie
After the glacier has melted a lake forms in the hollow. This is called a
corrie lake or tarn.
Large rocks (boulders) that have been carried and deposited by
glaciers as part of glacial till/moraine. They are usually made of a rock
type that would not be found in that area. - Erratics
Glacial Processes
● Weathering (Freeze-Thaw) - weaken bedrocks
● Erosion (Plucking & Abrasion) - U-shaped valleys, truncated
spurs, fjords, misfit rivers, ribbon lakes, hanging valleys,
waterfalls, corries, tarn
● Transportation & Deposition (Moraine/Glacial till, meltwater)
Deposited moraine = glacial till
Unit 14 — Middle East
*Physical Geography*
★ Middle East - region (go die if u think it is a continent, ur whole birth is
a lie if u think middle east is a continent)
★ Region - an area with certain common characteristics
★ no single definition of what countries make up the Middle East
Middle East = Southwest asia
→ Becomes a dominant region after WWII
Ankara → capital of Turkey (both in Asia and Europe)
Snows in parts of middle east - Lebanon
Crude oil is the most abundant natural resource in the Middle East.
An oil refinery is where crude oil is refined into petroleum products such
as diesel, gasoline, and heating oils.
Peninsula = a piece of land that sticks out from a larger area of land
into the sea or a lake (e.g. Arabian Peninsula)
The Arabian peninsula is mainly covered by the Arabian Desert - 2nd
largest sand desert
Rub' Al Khali (Means "Empty Quarter") in the Arabian Desert
Desert (Arabian peninsula) / Mediterranean climate (North) / Steppe
(Grassland)
The Mediterranean climate (Hot, dry summers & Cool, wet winters)
The North (Mediterranean climate) has more water than the South (Desert
climate)
Arabian Sea is apart of Indian Sea
How do they get water?
Desalination brines
- Getting steam and making it a drinkable water
Underground aquifers, Saudi Arabia
- Aquifers = Underground reservoirs of water in rock, sand and gravel
Unit 15 — Climate Change
Climate
- average weather of the whole year (long
term)
- average weather of the atmosphere over
a long term
Weather
- weather for today (sunny, rainy) aka
daily term
- condition of the atmosphere over a
short term
- Earth’s average temperature → 14’C
- Human activities caused global warming like burning fossil fuels to
generate electricity.
Greenhouse
- made with glass, for plants to give heat
Greenhouse Effect
- the gases(water vapour/CO2) trap the Sun’s heat with the atmosphere
Greenhouse Gases (GHG)
- The heat-trapping gases in our atmosphere includes:
1. Carbon dioxide
2. Water vapour
3. Methane
4. Nitrous oxide
5. Ozone
- The Earth produces Greenhouse Gas (GHG) is produced naturally
Greenhouse Gases - Natural Cause
- Water Cycle
- Plants, Animals, and Humans
- Volcanic eruptions
1. Water Cycle (from water vapour)
- Evaporation from the Earth’s water cycle adds water vapour to the
atmosphere
2. Animals & Humans & Plants (CO2 and Methane)
- Animals, Plants, and Humans release carbon dioxide when we
breathe by exhaling the air)
- Release carbon dioxide as we exhale
- When living things die, they decompose and release Co2 and
Methane
3. Volcanic Eruptions (CO2)
- Volcanoes —both on land and under the ocean — release carbon
dioxide as they erupt.