Lecture 4- Reducing Vulnerability To Earthquakes

Question 1

What must preparedness/ emergency planning be?

Answer 1

On a long-term basis

Question 2

What are the 6 steps of reducing vulnerability to EQs?

Answer 2

1. Hazard assessment
2. Land-use planning
3. Enforced anti-seismic building codes
4. Education, training, emergency planning
5. Earthquake insurance
6. Earthquake early warning systems

Question 3

What is probabilistic forecasting?

Answer 3

Finding the likelihood of a hazard event occurring in s given region, of particular magnitude

Question 4

Define probabilistic forecasting in terms of time?

Answer 4

The MAXIMUM INTENSITY earthquake which has a 10% probability of occurring within a 50 year period, in a given location

Question 5

What are produced during hazard assessments?

Answer 5

Microzonation maps

Question 6

What take us a typical 5-40% of rebuild costs after EQs?

Answer 6

Retrofitting existing structures

Question 7

What are dampening structures?

Answer 7

Ones that permanently deform during EQs, and must be replaced after every one

Question 8

What is the ideal height to width ratio of a seismic structure?

Answer 8

<4

Question 9

What should be avoided when constructing a seismic structure?

Answer 9

Different: size, shape materials as these will have differential stress responses and could cause the building to fall apart

Question 10

What is the take up of EQ insurance in California?

Answer 10

<25%

Question 11

What are the two approaches to earthquake early warning systems?

Answer 11

1. Single system approaches

2. Network approaches

Question 12

Outline a single system approach to earthquake early warning

Answer 12

Only needs detection of the FIRST P WAVE. To sound an alarm, and these are typically found in high risk localities such as hospitals

Question 13

What is the biggest problem associated with single system earthquake warning approaches?

Answer 13

Many false alarms due to reduce accuracy

Question 14

Detail a network approach to earthquake early warning

Answer 14

-requires the data from thee differing stations to find :magnitude, intensity, epicentre
This warning is transmitted by satellite, to allow for a few brief seconds warning
-slower than single system approaches as requires data from THREE seismographs

Question 15

What type of structure should be avoided in anti seismic buildings?

Answer 15

Soft storeys

Question 16

Hoe are anti seismic structures tested?

Answer 16

Shake tables or computer models