Tectonic Processes And Hazards

Question 1

What are the 5 types of plate boundaries?

Answer 1

-destructive
-constructive
-transform (conservative)
-collision
-complex

Question 2

Describe a constructive plate boundary with an example

Answer 2

Where two plates (usually oceanic) diverge.
Example: between the Nazca and Pacific Plates

Question 3

Describe a transform (conservative) plate boundary and give an example

Answer 3

When two plates move alongside each other, so conserving their size.
Example: between the pacific and north American plates

Question 4

Describe a collision plate boundary and give an example

Answer 4

When two CONTINENTAL plates converge.
Example: between Altiplano and South American plates

Question 5

Describe a complex plate boundary and give an example

Answer 5

Where several types are found along a relatively short distance.
Example: north-east of Caribbean plate

Question 6

What is the pacific ‘ring of fire’

Answer 6

Its the eastern part of the pacific where there are varying sizes of tectonic plates and types of plate boundaries

Question 7

What are the 3 causes of tectonic hazards

Answer 7

-volcanic
-earthquake
-tsunamis

Question 8

How do volcanos cause tectonic hazards

Answer 8

Volcanoes, often explosive, are found in the Andes fold mountains because unstable mantle material and melted oceanic plate force their way to the surface.
• Gentle volcanic activity is found at constructive plate boundaries as mantle material moves upwards to fill the gaps left by diverging plates, for example, between the Nazca and Pacific plates.

Question 9

Where are explosive volcanos found?

Answer 9

Andes fold mountains

Question 10

An example of gentle volcano activity causing tectonic hazards

Answer 10

Between the Nazca and pacific plates

Question 11

How do earthquakes cause tectonic hazards

Answer 11

Constructive plate boundaries only have small earthquakes, as there is not much friction or strain as plates diverge.

• Transform plate boundaries (conservative) have a large amount of friction, and when strain is neleased the shockwaves can be strong.

-Converging plates create the largest amount of friction and strain, with earthquake focal points following the Benioff zone to considerable depths.

Question 12

How do tsunamis cause tectonic hazards?

Answer 12

depths.
* An upward oldownward movement of the crust must disturb a mass of seawater.
This movement will be associated with an undersea carthquake, and so is usually linked to a destructive (convergent) plate boundary

Question 13

What is an intra-plate processes

Answer 13

Earthquakes and volcanoes are also found towards the middle of a plate (intra) away from the boundaries.

Question 14

Where can earthquakes happen

Answer 14

-They can happen anywhere the crust is cracked.
-isostatic readjustment
-human activities

Question 15

How can cracks in the crust cause intra-plate earthquakes

Answer 15

-Cracks in the crust are usually ancient faults created by previous plate movement.

-small movements along these old faults build friction and strain which when released causing low magnitude earthquakes

Question 16

What is isostatic readjustment and how does it cause intra-plate earthquakes

Answer 16

It is the weight of ice removed after the ice age.
It can cause earthquakes as the earth crust moves up or down

Question 17

How does human activity cause intra-plate earthquakes with an example

Answer 17

Human activity can also trigger tremors;
Examples:
- weight of water in a reservoir
-fracking of gas
-large explosions

Question 18

Where can intra-plate volcanoes occur

Answer 18

Volcanic activity can be found in the both the MIDDLE of OCEANIC and CONTINENTAL plates.

Question 19

How do intra-plate volcanoes occur on oceanic plates?

Answer 19

-oceanic plates are 7km thick.
-magma rising through the mantle from the edge of the outer core is able to melt its way through, forcing molten material to the surface, creating volcanoes that grow from the seabed.

Question 20

How do intra-plate volcanoes form on continental plates

Answer 20

-continental plates are thicker than oceanic plates.
-but they get stretched enough in places for the magma from a hot sport, linked to a mantle plume, to break through and form a volcano

Question 21

Case study of an intra-plate earthquake

Answer 21

-the United Kingdom
-the UK experiences minor earthquakes despite being 1500km from the nearest plate boundary under the centre of the Atlantic ocean.
-there about 25 earthquakes in the UK each year that are felt by people.
-the largest occurred in 1931 under the North Sea at Dogger Bank (6.1 on the richter scale)

Question 22

Largest intra-plate earthquake in the UK

Answer 22

1931
North Sea at Dogger Bank
6.1 on the richter scale

Question 23

Case study of intra-plate volcanoes

Answer 23

-Hawaii
-Hawaii islands have 15 volcanoes
-These 15 are the youngest of 130 found along a 6000km line to their north west.
-Kilauea and Mauna Loa are the most active volcanoes on the planet.
-the submarine volcano Lo’ihi is the youngest in the Hawaiian chain, being created as the pacific plate moves north-westwards over the hot spot

Question 24

Which volcano is the youngest intra plate volcano in the Hawaii chain

Answer 24

the submarine volcano Lo’ihi is the youngest in the Hawaiian chain, being created as the pacific plate moves north-westwards over the hot spot

Question 25

Which intra-plate volcanoes are the most active volcanoes on the planet

Answer 25

Kilauea and Mauna Loa (Hawaii)

Question 26

How many mantle plumes in the Earths mantle layer?

Answer 26

2 massive plumes:
-one centred under the pacific plate
-under the African plate

Question 27

What are mantle plumes

Answer 27

Molten viscous silicate material rises from the outer core/mantle boundary to about 700km the beneath the lithosphere (crust).

Question 28

What are hot spots?

Answer 28

-hot spots form from mantle plumes.
-they are created where magma rises through the asthenosphere and sometimes breaks through the crust.
-isolated hot spots occur where there is an upwelling of molten material directly from the outer core/mantle boundary to the surface.

Question 29

How do isolated hot spots occur

Answer 29

isolated hot spots occur where there is an upwelling of molten material directly from the outer core/mantle boundary to the surface.
E.g. the Hawaiian islands