LC Geography: Short Questions - Physical Geo

Name the 2 different types of the Earth's Crust

- Continental

- Oceanic

Explain what these 2 crusts consist of. (Thickness, Structure, Minerals)

Continental Crust

- Thickness: 30km => 60km (at mountain belts, continents squashed)

- consist of younger, lighter rocks => Granite

- Sial (Silica + Aluminium)

Oceanic Crust

- thickness: 5km => 10km

- on top => blanket of sediment (Clay + Shells)

- beneath this blanket: ancient, heavy rocks (Basalt)

- sima (Silica + Magnesium)

Crust

- outermost layer

- solid rock

- two types: Continental and Oceanic

Mantle

- 75% of Earth's volume

- several layers of rock

- rock varies: semi-molten at surface => molten deeper down

Outer Core

- consist of mainly Iron

- so hot that it is in constant molten state

Inner Core

- Consists of Iron + Nickel

- hottest layer of Earth

- solid because under such intense pressure

How old is the Earth

4.6 billion years old

Moho

boundary between crust and mantle

What is the Lithosphere

- Crust + upper mantle (asthenosphere)

- depth of 150km

- strong + rigid

What is the Asthenosphere

- a plastic layer of rock in the mantle

Define Continental Shelf

The submerged edge of a continent where the sea is relatively shallow compared with the open ocean

Explain plate tectonics

Define Plates

Very large sections into which the outer layers of Earth are broken

What does the theory of plate tectonics say?

That the lithosphere is divided into large, rigid sections called plates, which move slowly on the semi-molten mantle. The theory then evolved into two other theories: Continental Drift + Sea-Floor Spreading

Explain the theory of Continental Drift.

- suggests that plates have not always been placed in their present positions, and they continue to move

- plates once formed single land mass "Pangea"

- broken up 200million years ago, broke up into several land masses

What evidence is there to support the theory for continental drift

- Continental Fit

- coastlines of continents fit together; if pushed together

- continents surrounding Atlantic Ocean

- Africa + East Coast of North/ South America

- coastlines changed by erosion + deposition; almost perfect fit at the edge of the continental shelf

-Matching Rocks and Mountains

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-

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-Matching Glacial Deposits

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Explain the theory of Sea-Floor Spreading

- This theory suggests that ocean floors are widening and new rock is being formed where the plates originally separated.

- begins with cracking of lithosphere. As the plates separate, molten magma rises from within the mantle to fill the opening. When it cools and solidifies, new crust is formed and leads to formation of new ocean floor. Older crust moves away from center to be replaced by younger crust

Explain how Plates move.

- By thermal convection currents in the mantle

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List the types of plate boundaries

divergent, convergent, transform

Give an example of each of the previously mentioned plate boundary and what they have formed

- oceanic oceanic Divergence => Eurasian - North American

- oceanic continental divergence =>

- oceanic continental Convergence => Nazca - south American

- Transform => North American - Pacific

Under the following headings explain Oceanic Divergent plate boundary: Process, Type of Boundary, Landforms

Process; Sea-floor spreading

Type of Boundary; divergent (oceanic)

Landforms; Mid - ocean ridges, volcanic islands

Under the following headings explain Continental Divergent plate boundary: Process, Type of Boundary, Landforms

Process; plate separating

Type of Boundary; divergent (continental )

Landforms; Rift Valleys, New Seas

Under the following headings explain oceanic oceanic Convergent plate boundary: Process, Type of Boundary, Landforms

Process; plate collision

Type of Boundary; convergent (oceanic - oceanic)

Landforms; island arc, ocean trench

Under the following headings explain Transform plate boundary: Process, Type of Boundary, Landforms

Process; Plate collision

Type of Boundary; Transform

Landforms; fault lines

List any 3 characteristics of Transform plates

- plates slide past each other

- crust is neither created nor destroyed

- pressure is built in between the two plates due to friction

List and explain the evidence for continental drift

1. Continental Fit

2. Matching rocks and mountains

3. Matching glacial deposit

4. Matching fossils and rock types

Elaborate on Continental Fit

- Coasts of continents fit together like Jigsaw piece

- Africa -> north + South America

- although coastline changed by erosion + Deposition, almost perfect fit at edge of continental shelves

Elaborate on Matching Rocks + Mountains

- match on both sides of North Atlantic Ocean, Appalachian mountains USA + Caledonian Ireland, Britain , Scandinavia, North West Africa

- mountains have same structure, same direction, similar age, same rock type

Elaborate on Glacial Deposits

- Ancient glacial deposits in South America, Africa, India, Australia match

- ice-sheets cant form at these locations atm (hot + tropical) so they must've formed during times when these locations were cold and joined together

Explain the term Pangae

- all land 200 million years ago all continents joined together

What are Laurasia and Gondwanaland

List two pieces of evidence to suggest that North America and Europe were once linked

- matching Caledonian and Appalachian mountains ranges

What evidence is there for the theory of Sea-Floor spreading

Sea-Floor spreading

Explain the term plate divergence

Plate separation

Explain the term mid ocean ridge

An underwater mountain range produced by the process of sea-floor spreading

Give two pieces of evidence that the Atlantic Ocean is getting wider

- younger ocean floor spotted in the middle as opposed to the older floor shifting away to the side

- the American plate moves apart from the Eurasian and African plate at a speed of 2.5 cm each year

Explain the following terms: destructive boundary, ocean trench, island arc

Destructive boundary - 2 plates collide into each other, destroying crust as a result

Ocean trench -

Island arc -

Explain with the aid of a diagram how the Himalayas were formed

- plate convergence occurred with the Indian and Eurasian plates

- Indian plate drove northwards into the Eurasian plate and the intense pressure fractures the edge of both of the plates and fores them to buckle upwards creating a fold mountain range

Give 2 reasons why the Himalayas are so high

- the Himalayas continue to grow due to continual pressure being made by the Indian plate, pressure of 3 cm per year

- the growth has been happening for over the previous 10 million years

Explain the term Fault line

The line along which the plates slide past each other

Name any 2 volcanoes within the Ring of Fire

- Mount St. Helens

- Mayon volcano

- Mount Merapi

- Santa Maria

Explain the term volcanic activity

Refers to all events where molten rock is involved

Name 4 locations were volcanic activity is most likely to occur

1. convergent plate boundary (subduction)

2. Divergent plate boundary ( sea-floor spreading)

3. Where plates are breaking apart (rifting)

4. At hot spots

Explain the term the "Ring of Fire"

The belt of volcanoes which contains 75% of all volcanoes on the earth

Why do volcanoes occur/ erupt ?

Explain and give an example of what an Active Volcano is

Mount Etna - volcanoes which erupt regularly/ show signs of unrest

Explain and give an example of what a Dormant Volcano is

Mount St. Helens - volcanoes which haven't erupted for at least 600 years and are now quiet

Explain and give an example of what an Extinct volcano is

Slemish Mountain, Antrim - will never erupt again, volcano no longer has a lava supply

Name 3 types of volcanic material

- Lava

- Pyroclastic material

- gases

Explain the following term: Lava

main output of volcanoes

Explain the term Basic Lava

- Low in silica content

- very hot (over 1,000 degrees centigrade)

- runny

- produced at constructive plate boundaries + hotspots

- flows for great distances before solidifying

- forms extensive, gently sloping landforms (Antrim-Derry Plateau)

Explain the term Acid Lava

- high in silica content

- less hot (800 degrees centigrade)

- pasty

- produced at destructive plate boundary

- flows for short distances before cooling + hardening

- tends to produce steep-sided + localised landforms (Mount St. Helens)

Distinguish the difference between Basic and Acidic lava

Explain the terms Pyroclastic flow and give an example

- huge quantities of broken rock that erupts from volcanoes

- ash, cinders, bombs, pebbles, rocks, dust

Pyroclastic flow

the flow of ash, cinders, bombs, and gases down the side of a volcano during an explosive eruption

What are volcanic gases? (Consist of, come from,, etc)

- steam , carbon monoxide, chlorine and hydrogen

- largest portion, Water Vapour from cooling steam

- comes from Groundwater + Seawater, trapped in subducted rocks

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List three types of Extrusive Volcanic Landforms.

- Central vent eruption

- fissure eruption

- hot spot eruption

Explain the term intrusive

Indicates "inside"

Explain the term extrusive

Indicates "outside"

Explain process of Central Vent Eruptions

- volcanic material spews from vent/ opening

- central vent connected at depth to magma chamber, main storage area for volcanic material

- occur at destructive boundaries

- Lava + other volcanic material, pour out + build up around vent

- cone shaped mountain formed

- steep-sided depression crater

- floor may consist of lava lake

Explain the term "Composite Volcano"

- consists of alternate layers of Lava + pyroclastic material

Explain the term "Lava dome"

Explain the term " Caldera"

List 4 Intrusive Volcanic Landforms

Explain the term "plutons"

List and explain 3 ways in which volcanic activity could be predicted

List 3 ways by which people can benefit from volcanic activity

List and explain 3 risks associated with volcanic activity

Explain how the Leinster batholith was formed

How was the Leinster batholith exposed?

Briefly explain why volcanic activity occurs in ireland

Explain the term "Earthquakes"

Explain the term "Seismic Waves"

Explain the term "Tremors"

Explain the term "Foreshocks"

Explain the term "aftershocks"

Which point does the earthquake originate from: focus or epicentre

What causes Earthquakes?

Where do most Earthquakes occur?

Name the most active Earthquake zone

Pacific Belt

Name the three types of waves which Earthquakes are caused by (3 types of Seismic Waves)

Name the scale and instrument used to measure Earthquakes

How is an Earthquake measured using the named instrument

What is the magnitude in terms of Earthquakes

Define magnitude

List 3 advantages of being able to predict when an earthquake is about to occur

Why is it so difficult to predict earthquakes?

List 3 factors that influence the amount of damage caused by an earthquake

Define Soil Liquefaction

What is a "Tsunami"

The ability of a country to limit the effects of earthquake damage may be lined to its level of economic development. Explain why this is so

What year did the Haiti earthquake occur?

On the Richter Scale, what magnitude was the Haiti Earthquake

Where did the Haiti earthquake occur?

What type of fault formed this earthquake? (Haiti Earthquake)

List 4 immediate after effects of the earthquake

List 4 short term responses of the Haiti Earthquake

List 4 longer term impacts/ responses

(Haiti Earthquake)

What year did the Japanese earthquake and tsunami occur

What did the Japanese earthquake and tsunami measure on the Richter scale