CAIE IGCSE GEOGRAPHY

Flashcards related to geological activity

What is Lava?

Magma that reaches the surface

What are Pyroclastic flows?

Clouds of mixed poisonous gases and ash

What is Ash?

Very fine-grained volcanic material

What are Lahars

Snow and ice melt and combine with the ash, creating ____.

What is the main vent?

Central tube through the volcano

What are secondary cones

Eruptions from other vents lead to the formation of _ on the sides.

What is a Crater?

Bowl-shaped basin at the top of the volcano

What is a Magma chamber?

A large underground pool of magma

How do volcanos contribute to fertile soils?

The cooled lava contains minerals, leading to a high yield of crops.

Why is Tourism an oppurtunity created by volcanoes?

Many people want to visit the area and study it.

Why are Minerals and precious stones opportunities from volcanoes?

They can be sold, providing more work and income.

What is geothermal energy

The magma gives out heat, which can be used to generate _.

How do volcanoes create new land areas?

Once the lava and ash cool forms new fertile land.

What is an Active volcano?

Has erupted recently and is likely to erupt again.

What is a Dormant volcano?

Has not erupted recently but may in future

What is an Extinct volcano?

No evidence to erupt again.

What are characteristics of Low viscosity lava volcanoes?

Low in height, gently sloping sides with a broad base

What are characteristics of Viscous lava volcanoes?

High in height, steep-sided volcanic cones

What is the constructive

At _ margin, plates move away from each other; magma rises to fill the gap.

What happens at destructive margins?

Oceanic crust melts from friction and heat from the mantle; newly formed magma is lighter, so it rises to the surface

What is an Earthquake?

A sudden violent shaking of ground followed by a series of vibrations or movements in the earth's crust.

What is the Focus?

Point of earthquake

What is the Epicentre?

Point directly above the focus, on the ground

What is the Subduction zone?

Occurs at a destructive margin; one plate goes under the other

What is the Magnitude of an earthquake?

The amount of energy released.

How can we predict earthquakes?

Measure earth tremors, pressure, and release of gas

How can we prepare for earthquakes?

Build earthquake- proof buildings

What geological activity occurs at constructive plate boundaries?

Gentle volcanoes and gentle earthquakes

What geological activity occurs at destructive plate boundaries?

Violent volcanoes and violent earthquakes. Can also create fold mountains

What geological activity occurs at collision plate boundaries?

Create violent earthquakes and fold mountains

What geological activity occurs at conservative plate boundaries?

Create violent earthquakes

What are characteristics of the oceanic crust?

The oceanic crust is thinner (5-10km) but heavier and denser

What are the characteristics of the continental crust?

The continental crust is thicker (25-90km) but is older and less dense.

What is a Drainage basin?

The area of land drained by a river.

What is a Catchment area?

The area within the drainage basin.

What is a Watershed?

The edge of a highland surrounding a drainage basin.

What is the Source of a river?

The beginning or start of a river.

What is a Confluence?

The point at which two rivers or streams join.

What is a Tributary?

A stream or smaller river joins a larger stream or river.

What is the Mouth of a river?

Where the river ends, usually when entering the sea.

What is an input in a drainage basin?

Precipitation

What is a transfer in a drainage basin?

Infiltration, percolation, surface runoff, through flow & groundwater flow

What is storage in a drainage basin?

Interception, surface storage, soil moisture storage & groundwater storage

What is an output in a drainage basin?

Evaporation & transpiration or evapotranspiration

What is Erosion?

The wearing away of surfaces.

What is Attrition?

Large particles such as boulders collide and break into smaller pieces.

What is Hydraulic action?

Flowing water hits against the riverbanks and beds.

What is Abrasion?

Smaller particles rub against the riverbanks and bed like sandpaper.

What is Solution?

Acid in rivers dissolves rocks

What is Vertical erosion?

Dominant in the upper course of rivers. It increases the river's depth and valley as the river erodes downwards.

What is Lateral erosion?

Dominant in the middle and lower course of rivers. It increases the width of the river and valley as it erodes sideways.

What is Traction?

Rolling stones along the bed

What is Saltation?

Small particles bounce along the bed in a leapfrog motion

What is Suspension?

Silt and clay-sized are carried within the water flow

What is Deposition?

When a river lacks the energy to carry its load, it deposits the heaviest particles.

What is Swash?

When a wave breaks & washes up the beach

What is Backwash?

When the water drains back into the sea

What are characteristics of Constructive waves?

Low wave height, the beach gradient is gentle, spill forward gently, creates a strong swash, water drains through beach material

What are characteristics of Destructive waves?

High wave height, the beach gradient is steep, plunge forward, swash is weak, rotation of water causes a strong backwash

What is Abrasion in coasts?

Larger rocks and sediments like boulders grind against the riverbed

What is Corrosion in coasts?

Salts and acids slowly dissolve a cliff

What is Attrition in coasts?

Smaller sediments collide with each other while moving in the flow, making them rounder and smaller

What is Hydraulic action in coasts?

The force of waves compresses air in cliffs

What is Longshore Drift?

Waves approach the coast at an angle; swash moves up the beach at an angle; backwash drains straight back down the beach

What are the advantages of Sea walls?

Reduce erosion and prevent flooding; curved structure breaks waves

What are the disadvantages of Sea walls?

Very expensive and big, requires constant maintenance

What are the advantages of Groynes?

Increases distance between waves and coasts → Waves lose energy → Reduces impacts of waves.

What are the disadvantages of Groynes?

Certain sections of the coast may be more exposed to erosion

What are the advantages of Gabions?

Reduces the impact of waves on a cliff, prevents cliff from being undercut, and is cheap

What are the disadvantages of Gabions?

Not as effective as other coastal defenses

What are the advantages of Revetments?

Absorbs energy of waves, prevents cliffs from being eroded; Rippled surfaces help dissipate wave energy; and require no need for much maintenance

What are the disadvantages of Revetments?

Expensive

What are the advantages of Rip-raps?

Absorbs wave energy, protects cliffs behind

What are the disadvantages of Rip-raps?

Visual pollution, susceptible to being moved by the sea

What are the advantages of Breakwaters?

Effective, breaks incoming water

What are the disadvantages of Breakwaters?

Visual pollution, easily destroyed

What are the advantages of Tidal barriers?

Prevents storm surges, very effective

What are the disadvantages of Tidal barriers?

Expensive

What are the advantages of Beach nourishment?

Increases distance between waves and cliffs → Waves lose energy → Less erosive power.

What are the disadvantages of Beach nourishment?

Effectiveness is uncertain

What are the advantages of Land management?

Good barrier against coastal flooding and erosion

What are the disadvantages of Land management?

Tourism is affected as dunes are marked out of bounds to the general public

What are the advantages of Marshland?

Break up waves and reduce speed and power of waves → Limits area which waves can reach → Prevents flooding

What are the disadvantages of Marshland?

Effectiveness is uncertain

What are the advantages of Beach stabilization?

Widen beach and reduces wave energy, lowers the profile of the beach

What are the disadvantages of Beach stabilization?

Effectiveness is uncertain

How are cliffs and wave-cut platforms formed?

Wave erosion is concentrated at the foot of the cliff; a wave-cut notch is formed; repeated collapse causes retreat of the cliff

How are caves, arches, and stacks formed?

Erosion produces caves on both sides of the headland; more erosion produces an arch; eventually, the roof collapses, forming a stack.

Where are beaches formed?

In bays, the waves diverge outwards, creating a low-energy environment for deposition to form beaches.

How are Bays and Headlands formed?

Softer rock erodes easily, creating Bays; resistant rock erodes more difficultly, creating headlands.

How are Spits formed?

Longshore drift carries material; sand & shingle builds up; the end of the spit curves due to wave refraction or wind.

How are sand dunes formed?

Onshore winds pick up dry sand and deposit it in the lee of obstacles, eventually plants grow on it, stabilizing it and trapping more sand