3.a earthquakes features

Question 1

identify the type of quakes that occur on a constructive / divergent plate boundary

Answer 1

tension quakes

Question 1

define the term earthquake

Answer 1

represent the release of stress that has built up within the earth’s crust caused by tension,compression or the shearing of rocks.

Question 2

explain features of earthquakes at constructive/divergent plate boundaries

Answer 2

• tension released as a result of magma being erupted out of volcano / creation of new crust
• Rising magma and collapse of crust both causing stretching and faulting
• Shallow quake - mainly submarine (below the sea)
• Low hazard / mainly of a low magnitude → as there is no contact of the plates

Question 3

what quakes occur at a destructive / convergent plate boundary?

Answer 3

compression quakes

Question 4

explain the features of earthqquakea at destructive / convergent plate boundaries

Answer 4

• Faulting and fracturing occurs along the whole of the benioff zone resulting with earthquakes at a range of depths
• High hazards as a whole fault often affected
• Megathrust(another name for them) can lead to tsunamis

Question 5

Identify what quakes occur at a collision plate boundary

Answer 5

compressional

Question 6

features of earthquakes at a collision plate boundary

Answer 6

• Shallow quakes dissipated over a broad area
• Can be high hazard
• Plates buckle and cause these compression shake

Question 7

identidy the names of quakes at a conservative plate boundary

Answer 7

Shearing quakes / strike slip quakes

Question 8

features of earthquakes at a conservative plate boundary

Answer 8

Mainly shallow with many fracture lines

Question 9

focus

Answer 9

Where the earthquake starts beneath the earth crust where it begins

Question 10

epicenter

Answer 10

the point on the earth’s surface vertically above the focus of an earthquake.

Question 11

fault scarp

Answer 11

A fault line that runs where there is a weakness / break in the ground caused by an earthquake

Question 12

Wave fronts

Answer 12

The boundary between seismic waves - gaps between them

Question 13

fault

Answer 13

A break in the ground caused by an earthquake.

Question 14

what are the two types of earthquakes?

Answer 14

1. depth of focus
2. seismic waves

Question 15

Explain shallow focus

Answer 15

when the epicenter is at occurs at depths less than 70 km
* Very common
* Occur in brittle rocks
* Many release low levels of energy but some are high energy quakes having greater devastating consequence→ so its VARIABLE

Question 16

explain a deep focus

Answer 16

occur at a great focal depth of over 70km with focus deeper below the epicenter
* Greater depth = greater pressure and temperature
* Generally poorly understood by scientists

Question 17

define seismic wave

Answer 17

Travel out from the focus and they will send the energy to the epicenter above but also to the ground and all around it → like a circular pattern affecting deep ground and surface

Question 18

Define primary waves

Answer 18

Fast waves that are compressional, vibrating in the direction that they are traveling.

Question 19

features of primary waves

Answer 19

• Low frequency
• Longitudinal waves
• can travel through solid and liquids

Question 20

define secondary waves

Answer 20

• travel at ½ speed of primary waves and shear rocks by vibrating at right angles to the direction of travel.

Question 21

explain features of secondary waves

Answer 21

• High frequency
• Transverse waves
• ONLY travel through solids

Question 22

What are surface waves ?

Answer 22

travel slowest and near to ground surface.Some of these waves shake the ground at right angles to the direction of the wave movement and some have a rolling motion that produce vertical ground movement
* Low frequency