Tectonics

Question 1

Why are some locations more at risk from tectonic hazards?

Answer 1

Because tectonic hazards occur in specific locations, related to tectonic plate boundaries and tectonic events can generate multiple hazards when they occur.

Question 2

What process is tectonic hazards caused by?

Answer 2

Earths internal heat engine, radioactive decay of uranium and thorium isotopes in the earths core and mantle generates huge amounts of heat which flows towards the earths surface

Question 3

What does the plate sounds dumb type depend on?

Answer 3

The motion; moving apart(divergent), colliding(convergent) or sliding past each other(conservative or transform)

Plate type oceanic or continental

Question 4

Describe the difference between continental plates and oceanic plates?

Answer 4

Continental plates make up the earth’s land masses, are much thicker 25-70km, less dense and made of granitic rock

Oceanic plates make up the sea floor, are denser, made of basaltic rock and are 7-10km thick

Question 5

What are mantle plumes?

Answer 5

Mantle plumes are concentrated areas of heat convection. At plate boundaries they are sheet like and at hot spots they are column like. Over a millennia they produce a chain of volcanic islands

Question 6

Describe divergent plate boundaries

Answer 6

It is two plates moving away from each other and new crust is formed from magma rising to the surface between the two plates. It’s features are volcanoes, earthquakes which are both not that violent. An example is the Mid ocean ridge

Question 7

Describe convergent place boundaries

Answer 7

Convergent plate boundaries are when a continental and oceanic plate meet and the denser oceanic plate is sub ducted underneath the earths surface. Strong earthquakes and volatile volcanic mountains or island aswell as ocean trenches

Question 8

Describe conservative plate boundaries?

Answer 8

They occur when plates slide past eachother in opposite directions or in the same direction but at different speeds, tension builds up when they get stuck and when friction is overcome the plates slip past in a sudden movement, shockwaves are released which can produce powerful earthquakes

Question 9

What was Alfred Holmes’ ideas

Answer 9

Earth’s internal radioactive heat was the driving force of mantle convection that could move tectonic plates

Question 10

What discovery was made in 1960

Answer 10

The asthenosphere a weak deformable layer beneath the rigid lithosphere on which the lithosphere moves

Question 11

What was the magnetic stripes discovery in the 1960s

Answer 11

Magnetic strips were discovered in the oceanic crust of the sea bed, they are ancient magnetism from past reversals of the earth’s magnetic field which prove that new oceanic crust is created by sea floor spreading at mid ocean ridges

Question 12

What was the magnetic stripes discovery in the 1960s

Answer 12

Magnetic strips were discovered in the oceanic crust of the sea bed, they are ancient magnetism from past reversals of the earth’s magnetic field which prove that new oceanic crust is created by sea floor spreading at mid ocean ridges

Question 13

What was the magnetic stripes discovery in the 1960s

Answer 13

Magnetic strips were discovered in the oceanic crust of the sea bed, they are ancient magnetism from past reversals of the earth’s magnetic field which prove that new oceanic crust is created by sea floor spreading at mid ocean ridges

Question 14

What was discovered first in 1965 and by who?

Answer 14

Transform faults by Tuzp Wilson

Question 15

What is the order of the theories of plate motion

Answer 15

Alfred Wenger continental drift , Arthur Holmes earths radioactive heat being the driving force of mantle convection which moves tectonic plates, asthenosphere, magnetic stripes new oceanic crust is made by sea floor spreading at mid ocean ridges

Question 16

What is slab pull

Answer 16

The motion of a tectonic plate that is subducted, plate motion is partly driven by the weight of cold dense plates sinking into the mantle at oceanic trenches

Question 17

How do earthquakes occur?

Answer 17

As tectonic plates attempt to move past each other along fault lines, they can stick and strain then builds up over and time as there becomes increasing stress. When this stress is released a pulse of energy radiates in all directions from the focus.

Question 18

Describe the 3 different types of seismic waves

Answer 18

Primary waves: they come first and fastest however they cause the least damage

Secondary waves: They arrive next and shake the ground violently, causing damage

Love waves arrive last as they travel across the surface, but they have a large amplitude and cause significant damage, fracturing the ground surface

Question 19

What can earthquakes do

Answer 19

Fracture the earth, buckle and fracture the ground surface, rupture a fault line, ground shaking and aftershocks

Question 20

What primary hazards can earthquakes cause?

Answer 20

Landslides, avalanches, liquefaction and tsunamis