Tectonics :)

Question 1

What is the lithosphere

Answer 1

the rigid outer part of the earth, consisting of the crust and upper mantle.

Question 2

What is the asthenosphere

Answer 2

the upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur

Question 3

What are convection currents

Answer 3

Convection currents describe the rising, spreading, and sinking of gas, liquid, or molten material caused by the application of heat. They move the tectonic plates

Question 4

Describe the structure of the earths layers

Answer 4

The earth is made up of three different layers: the crust, the mantle and the outer and inner core

Question 5

Describe the different crusts

Answer 5

• Oceanic crust
  (5-10km thick, dense)
• Continental crust
  (20-70km thick, less dense)

Question 6

Describe what the mantle is

Answer 6

the region of the earth’s interior between the crust and the core, believed to consist of hot, dense silicate rocks

Question 7

Describe what the inner and outer cores are like.

Answer 7

The inner core is under intense pressure, which keeps it solid despite high temperatures. Outer Core. The outer core, which is liquid, is about 1300 miles (2092 km) thick.

Question 8

What are the three different types of plate boundary?

Answer 8

• Destructive
  (plates moving into each other) (volcano)
• Conservative
  (slipping past each other) (faults)
• Divergent
  (moving away from each other) (rift valleys)

Question 9

Explain what a rift valley is

Answer 9

A rift valley is a lowland region that forms where Earth’s tectonic plates move apart

Question 10

What is a subduction zone

Answer 10

a region in which a portion of a tectonic plate sinks beneath another plate into the Earth’s interior. oceanic under continental

Question 11

what is slab pull

Answer 11

the force due to the weight of the cold, dense sinking tectonic plate. helps pull down the oceanic plate under the continental plate

Question 12

What is ridge push

Answer 12

magma rises as the plates move apart. The magma cools to form new plate material. As it cools It becomes denser and slides down away from the ridge. This causes other plates to move away from each other.

Question 13

what is palaeomagnetism

Answer 13

Palaeomagnetism is the study of the Earth’s magnetic field preserved in rocks. The discovery that some minerals, at the time of their formation, can become magnetised parallel to the Earth’s magnetic field

Question 14

What is the evidence for plate tectonics

Answer 14

• South America and Africa would fit nicely together
  -Fossils of animals on one continent found on another continent (mesosaurus)
• Coal found in Antarctica and UK (can only be made in tropical conditions)

Question 15

describe the distribution of earthquakes and volcanos

Answer 15

tend to follow patterns around the plate boundaries apart from hotspots like Hawaii.

Question 16

How do we measure earthquakes

Answer 16

with seismograph and with the richter scale (1-10)

Question 17

how do we measure volcanos

Answer 17

with the volcanic explosivity index (VEI)

Question 18

What are the primary effects of earthquakes

Answer 18

Primary effects of an earthquake can include the ground shaking, buildings collapsing, and the ground splitting

Question 19

What are the secondary effects of an earthquake

Answer 19

ground settlement, lateral ground displacement, liquefaction, landslides and rock falls, tsunamis, floods, fires and falling debris.

Question 20

describe liquefaction

Answer 20

Liquefaction takes place when loosely packed, water-logged sediments at or near the ground surface lose their strength in response to strong ground shaking. The buildings tend to sink/collapse

Question 21

What are the different types of volcano

Answer 21

• composite
  (The lava of a composite volcano is acidic and is of high viscosity, calmer)
• shield
  (The basaltic lava of a shield volcano is runny and is of low viscosity, violent)
• cinder cones
  (violent lava)
• lava domes
  (viscous lava calmer)

Question 22

Primary effects of volcanic eruptions

Answer 22

Pyroclastic Flows, Lava Flows, Volcanic Bombs and Tephra, Lahars

Question 23

secondary effect of volcanic eruptions

Answer 23

Widespread ash-fall or gas impact (acid rain) may lead to agricultural hardships including crop failure, loss of livestock and contamination of water supplies which, in turn, may trigger famine and related diseases.

Question 24

what is a lahar

Answer 24

A lahar is a destructive mudflow or debris flow composed of a mixture of volcanic ash, rocks, and water.

Question 25

what is a volcanic bomb and tephra

Answer 25

volcanos eject large rocks, called volcanic bombs, along with smaller rock fragments, ash, and dust, known as tephra

Question 26

why do volcanos erupt

Answer 26

Deep within the Earth, it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Since it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually, some of the magma pushes through vents and fissures to the Earth’s surface

Question 27

how can we predict tectonic hazards

Answer 27

• Seismic activity (seismograph)
• Seismic hazard zoning (understanding and mapping areas vulnerable from previous events)
• Earthquake precursors (signs/patterns observed before an earthquake, foreshocks, animal behaviour)
• Volcanic monitoring (gas emission measurements, ground deformation studies)

Question 28

How can we mitigate tectonic hazards

Answer 28

• land-use planning (restricting development in high-risk zones, promoting safer construction practices)
• building design and retrofitting (earthquake-resistant buildings, reinforced foundations and shock-absorbing materials)
• Early warning systems (alerts to the population)
• Education (educate people on the matter)

Question 29

How can we monitor tectonic hazards

Answer 29

• global monitoring networks (networks of monitoring facilities providing real-time data on tectonic activity)
• Remote sensing (satellite imagery and aerial surveys)
• Seismic monitoring
• volcano monitoring techniques (gas sampling, thermal imaging, ground temperature measurements)