Earthquakes

Question 1

What is the epicentre of an earthquake?

Answer 1

The point of the earth’s surface above the focus

Question 2

What is the focus of an earthquake?

Answer 2

The point at which an earthquake occurs

Question 3

What is an earthquake?

Answer 3

1) Movement within the earth’s crust causes stress to build up
2) When the stress exceeds the strength of the rock, the rock fractures
3) The stored energy is released as an earthquake
4) Intense seismic waves spread out from focus
5) Waves cause ground to shake
4) Shallow focus = more destruction

Question 4

What are P (primary) waves?

Answer 4

-Arrive at the detector first
-Longitudinal waves = Same direction of travel as the vibrations
-Travel through solids and liquids
-Can be detected on other side of the earth

Question 5

What are S (secondary) waves?

Answer 5

-Arrive at detector second
-Transverse = Vibrations go at right angled directions of travel
-Only through solids so only detected on the same side of the earth

Question 6

What is the Richter scale?

Answer 6

A scale used to measure earthquake
-Logarithmic scale -> Each point is 10x stronger than the last
-For each point, approx 30x more energy is released

Question 7

Primary effects of earthquakes

Answer 7

-Ground shaking
-Ground rupturing

Question 8

Secondary effects of earthquakes

Answer 8

-Soil liquefaction
-Landslides and avalanches
-Fires
-Tsunamis
-Effect on people and built environments

Question 9

Environmental impacts

Answer 9

-Potentially causes tsunamis, soil liquefaction, ground resonance, landslides, and ground failure + fires
-Water pollution
-Air contamination
-Loss of habitats due to fires, leaks of chemicals or radioactive material or tsunamis flood freshwater ecosystems

Question 10

Social impacts

Answer 10

-Damaged education systems
-Deaths and injuries = buildings collapsing
-Displacement and homelessness causing migration
-Disease outbreak due to lack of sanitation and broken sewage facilities
-Limited access to necessities
-Damaged homes due to flooding or general lack of strength

Question 11

Economic impacts

Answer 11

-Loss of jobs -> Tax fluctuations
-Business lose profits
-Costs of funding put governments in debts
-Cost of reconstruction
-Loss of infrastructure-> no healthcare, school, jobs and basic needs
-Become reliant on expensive imports due to damage

Question 12

Political impacts

Answer 12

-Conflicts with scares resources
-Aid from other countries
-Media and news portrayals
-Relocation of people out of the country
-Future planning

Question 13

Preparedness strategies

Answer 13

-Alarms, evacuation plans, food + water and medical supplies, warnings and monitoring

Question 14

Mitigation strategies

Answer 14

-Rubber shock absorbers built into foundations to absorb tremors, buildings reinforced with steal to sway with movements while providing stability, open areas for evacuation, light weight roofing to reduce injury if they fall through

Question 15

Prediction strategies

Answer 15

-monitoring fault lines, animal activity, seismometers and seismographs, remote sensing

Question 16

Prevention strats

Answer 16

Not possible for earthquakes, however you can help mitigate secondary effects e.g. building away from area likely to experience soil liquefaction and sea walls to prevent tsunamis impacts worsening