9. Managing Seismic Events

Question 1

Examples of prevention

Answer 1

• Fault lubrication
• Altering properties of soils
• Managed forests

Question 2

How does fault lubrication work?

Answer 2

Pumping water into fault plane allowing it to move more easily and frequently therefore, generating smaller, non-damaging earthquakes rather than storing up energy for a major earthquake.

Question 3

How does altering properties of soils work?

Answer 3

Drilling boreholes into the ground in such a way that the properties of soil are changed so that incoming earthquake waves would be reflected.
Additionally, concrete pillars could be dug into the ground to act as a seismic cloak to protect buildings.

Question 4

How do managed forests work?

Answer 4

Planting trees between buildings and a potential earthquake source.
The trees are planted in a wedge shape with tallest trees near to the earthquake source.
The Forest resonates with the most powerful seismic waves converting them into less destructive shear waves that travel down into the crust where they can do no harm.

Question 5

What is the effectiveness/ sustainability of the prevention techniques?

Answer 5

Technology is largely untested.
Question marks over amount of water required also suggests that fault lubrication is unfeasible and unsustainable.

Question 6

Examples of prediction

Answer 6

Scientists have identified a number of events that occur before an earthquake strikes:
- Microquakes before main event
- Bulging of ground
- Decreased radon gas concentrations in groundwater
- Raised groundwater levels
- Electrical and magnetic changes within local rocks
- Increased argon gas content in soils
- Curious animal behaviour

Question 7

How does prediction work?

Answer 7

Use seismometers to detect changes and monitor
Use to create seismic hazard maps and model the likely impacts of an earthquake on a locality.
Technology has allowed early warning systems such as shale alert

Question 8

What is the effectiveness/sustainability of prediction?

Answer 8

Prediction is very difficult, if not impossible at the current levels of technology

Question 9

Examples of adaptation/ mitigation

Answer 9

Hazard resistant structures:
- Large concrete on top of buildings
- Large rubber shock absorption foundations
- Cross bracing
- Retrofitting
- Hollow bricks, mud bricks, straw bricks

Question 10

How does large concrete blocks work?

Answer 10

Moves with the aid of a computer programme, in the opposite direction to the force of the earthquake in order to counteract stress

Question 11

How do shock absorbers work?

Answer 11

Allows some movement of buildings

Question 12

How does cross bracing work?

Answer 12

Hold buildings together better when it shakes

Question 13

How does retrofitting work?

Answer 13

Existent buildings are adapted to make them more earthquake proof

Question 14

How do hollow/ mud/ straw bricks work?

Answer 14

Lightweight to make buildings less dangerous if they fall down

Question 15

What is the effectiveness/ sustainability of adaptation/ mitigation?

Answer 15

Strategies are expensive so not everyone will be able to afford/ access them
Effective but costly

Question 16

Examples of preparation

Answer 16

• education
• fire prevention
• emergency services
• land use planning
• insurance
• aid
• tsunami protection

Question 17

How does education work?

Answer 17

Instructions issued by authorities on how to prepare for such events by securing homes, appliances and heavy furniture, teaching children.

Question 18

How does fire prevention work?

Answer 18

Smart meters developed to cut off gas if an earthquake of sufficient magnitude occurs.

Question 19

How do emergency services work?

Answer 19

Heavy lifting gear needs to be available, first aid training

Question 20

How does land use planning work?

Answer 20

Most hazardous areas identified and then regulated, have sufficient open space, put certain types of building in areas of low risk e.g. schools and hospitals

Question 21

How does insurance work?

Answer 21

Richer areas, people are encouraged to take out insurance to cover losses

Question 22

How does aid work?

Answer 22

Provide medical services, tents, water purification equipment, search and rescue equipment

Question 23

How does tsunami protection work?

Answer 23

Automated systems installed to give warnings, the best of which uses bottom pressure sensors, attached to buoys, which constantly measure the pressure of the overlying water column.
Monitors earthquake activity and issues warnings to countries around Pacific edge if tsunamis are likely.

Question 24

Effectiveness/ sustainability of preparation

Answer 24

• Lack of education in some areas, low socio-economic status have less access
• Smart meters won’t detect smaller magnitudes
• Emergency services needs careful and thorough organisation
• Good to form safe areas people can go to and reduce vulnerable areas
• Aid over long term can be problematic and can take days to come as it can increase death toll
• Tsunamis cannot be entirely predicted even if location and magnitude of earthquake is known