Tectonics Flashcards Preview

Geography > Tectonics > Flashcards

Flashcards in Tectonics Deck (20):
1

Why are some locations more at risk from tectonic hazards?

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

2

What process is tectonic hazards caused by?

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

3

What does the plate sounds dumb type depend on?

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

Plate type oceanic or continental

4

Describe the difference between continental plates and oceanic plates?

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

5

What are mantle plumes?

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

6

Describe divergent plate boundaries

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

7

Describe convergent place boundaries

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

8

Describe conservative plate boundaries?

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

9

What was Alfred Holmes' ideas

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

10

What discovery was made in 1960

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

11

What was the magnetic stripes discovery in the 1960s

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

12

What was the magnetic stripes discovery in the 1960s

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

13

What was the magnetic stripes discovery in the 1960s

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

14

What was discovered first in 1965 and by who?

Transform faults by Tuzp Wilson

15

What is the order of the theories of plate motion

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

16

What is slab pull

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

17

How do earthquakes occur?

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.

18

Describe the 3 different types of seismic waves

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

19

What can earthquakes do

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

20

What primary hazards can earthquakes cause?

Landslides, avalanches, liquefaction and tsunamis