2.1 Earth quakes and volcanoes

Question 1

Earthquakes:

Answer 1

• A series of vibrations or movements in the earth’s crust
• Caused when two plates ‘stick’; pressure builds up; one
  plate jerks forward sending shock waves to the surface

Question 2

Features of Earthquakes:
name 5

Answer 2

• Focus: point of earthquake
• Epicenter: point directly above the focus, on the
  ground
• Seismic waves
• Shaking ground
• Subduction zone: occurs at destructive margin, one
  plate goes under the other

Question 3

Effects of Earthquakes:
name 5

Answer 3

• Large number of deaths
• Fires breaking out
• Water pipes burst
• Water contamination, diseases
• Corpses: human & animal
• Accessibility difficult
• Building damaged/destroyed
• Tsunami can follow
• Reconstruction costs

Question 4

How to predict an Earthquake:

Answer 4

• Measure earth tremors, pressure, and release of gas
• Use maps and facts to find pattern in time/location
• Unusual animal behaviour

Question 5

Peperations for an Earthquake:

Answer 5

• Build earthquake-proof buildings and roads
• Train emergency services
• Set up warning system
• Create evacuation plan
• Emergency food supply
• Practice drills

Question 6

Earthquake Proof buildings

Answer 6

• Automated weights on roof to reduce movement
• Fire-resistant building material
• No bricks or reinforced concrete block
• Rubber shock-absorbers between foundations
• Foundation sunk deep into bedrock avoiding clay
• Roads to provide access by ambulances & fire engines
• Open areas where people can assemble if evacuated
• Automatic shutters come down over the windows
• Interlocking steel frames which can sway during earth
  movements

Question 7

Volcanoes:

Answer 7

A vent in the earth’s surface where magma, gas or ash
escapes onto the earth’s surface or into the atmosphere.

Question 8

Causes for volcanoes:

Answer 8

• At constructive margin: plates move away from each
  other; magma rises to fill the gap;
• At destructive margin: oceanic crust melts from
  friction and heat from mantle; newly formed magma
  is lighter so it rises to surface

Question 9

Volcanic plug:

Answer 9

lava shoots up, falls into vent & solidifies

Question 10

What are volcano layers made of

Answer 10

Ash, dust, rock and cooled lava

Question 11

Different types of volcanoes (3 types)

Answer 11

1. Active
2. Dormant
3. Extinct

Question 12

Active volcanoes:

Answer 12

has erupted recently

Question 13

Dormant volcanoes:

Answer 13

has not erupted recently but may in future

Question 14

Extinct volcanoes:

Answer 14

unlikely to ever erupt again; no magma inside

Question 15

Volcano appearences

Answer 15

Shield, Cone, Composite

Question 16

Shield volcanoes:

Answer 16

Gentle slopes, slow flowing lava

Question 17

Cone volcanoes:

Answer 17

Steep slopes, violent eruption

Question 18

Composite volcanoes

Answer 18

Mix of cone and shield, eruption varies in strength, made of layers of ash and lava (unstable)

Question 19

Volcano characteristics:

Answer 19

• Large Crater
• Lava vent
• Side vent
• Magma chamber

Question 20

Volcano hazards:

Answer 20

• Plume (ash cloud)
• Pyroclastic flow (most deadly hazard)
• Lava flow (lava is magma but when it is out of the
  volcano it is called lava)
• Lahars (violent type of mudflow or debris flow
  composed of a slurry of pyroclastic material, rocky
  debris and water)
• Landslides
• Dust, ash, steam, gas
• Volcanic bombs (rocks)

Question 21

Advantages of Volcano:

Answer 21

Tourist attraction:
- income and employment

Creates fertile soil:
- good agricultural land to grow crops

Geothermal heating:
- Renewable resource
- Heating (hot water)
- Geyser & mud baths

Question 22

Disadvantages of Volcano:

Answer 22

• Destruction of land, property, jobs, homes, transport
• Rebuilding costs
• Unemployment
• Fires breakout
• Diseases from poor sanitation
• Gas from eruption suffocates
• Pyroclastic flow

Question 23

Prediction for Volcano:

Answer 23

• Tremors within volcano
• Ground temps. rise
• Volcano swells & bulges
• Emits gas & steam
• Animal behaviour changes

Question 24

Preperation for Volcano:

Answer 24

• Set up warning system
• Create evacuation plan
• Train emergency services
• Organize post-eruption plan
• Emergency food supply

Question 25

Distribution of Volcanos and Earthquakes:

Answer 25

Where earthquakes occur and volcanoes form is
governed by plate tectonics

“Ring of fire”
a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes. Its length is approximately 40,000 kilometers (24,900 miles)

Question 26

Type of crust:

Answer 26

Oceanic and Continental

Question 27

Oceanic crust:

Answer 27

younger, heavier, can sink and is
constantly being destroyed and replaced

Question 28

Continental crust:

Answer 28

older, lighter, cannot sink and is permanent

Question 29

Plate movement:

Answer 29

Plate movement is caused by convection currents in the
mantle

Question 30

Earthquake locations:

Answer 30

• Encircle the whole of the Pacific Ocean
• Extend down entire length of the mid-Atlantic Ocean
• Stretch across southern Europe and Asia

Question 31

Volcano locations

Answer 31

• Encircle the whole of the Pacific Ocean
• Extend down entire length of the mid-Atlantic Ocean
• Some in southern Europe, the Caribbean & east Africa

Question 32

Subduction zone:

Answer 32

Subduction occurs when an oceanic plate runs into a continental plate and slides beneath it.

Question 33

Plate boundaries:

Answer 33

1. Collision
2. Constructive / Divergent
3. Destructive / Convergent
4. Conservative / Transform

Question 33

Collision plate boundary

Answer 33

• occur when two continental plates move towards each other.
• Volcanoes: none
• Earthquakes: violent
• Form fold mountains

Example: Indo-Australian and the Eurasian Plate

Question 34

Constructive / Divergent plate boundary

Answer 34

• occur when two plates move away from each other.
• Volcanoes: Gentle
• Earthquake: Gentle
• Don’t form fold mountains

Example: North American and Eurasian Plate

Question 35

Destructive / Convergent plate boundary

Answer 35

• occur when two plates slide past each other.
• Volcanoes: Violent
• Earthquakes: Violent
• Form fold mountains

Example: North American Plate and the Pacific
Plate

Question 36

Conservative / Transform plate boundary

Answer 36

• occur when oceanic plate is subducted by a continental
  plate.
• Volcanoes: non
• Earthquakes: violent
• Don’t form fold mountains

Example: pacific plate and the Eurasian plate