1. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake “forecasting” (prediction)
Engineering and Building Codes
Preparation in earthquake prone areas

2. VII. Earthquake Mitigation
Approach to earthquake mitigation
Main approach is survivability
Requires hazard identification and risk assessment
Identify areas of where materials at risk of seismic wave amplification and enhanced ground shaking risk
Engineering solutions to make structures earthquake resistant
Preparation and training of emergency response teams and medical personel
Earthquake prediction and evacuation is not a reasonable goal in the foreseeable future

3. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Hazard Identification: deals primarily with the science
defining and describing a hazard, its physical characteristics, magnitude and severity, probability and frequency, causative factors, and locations or areas affected
Risk Assessment: deals with the societal impact issues
Estimating vulnerability of and impact on populations, probabilities of events and magnitude, frequency and return period, mitigation planning

4. VII. Earthquake Mitigation
Hazard Identification and Risk Assessment
Shaking Hazard map = statistical probability (10% chance in 50 year period) exceeding a stated level of shaking (as % of g = acceleration of gravity)
Need to know…
Probability of a future EQ of given magnitude
(need to understand past behavior and how faults work)
Response of materials to shaking (intensity)
(need to understand how shaking varies with materials and how materials vary with geographic location)

5. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake “forecasting” (prediction)
Long-term forecasting (probabilities of future fault slip)
Based on past behavior
Historical records + pre-historical records + fault mapping = total record

6. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake prediction
Long-term forecasting (probabilities of future fault slip)
Historical Records
written and verbal accounts (100s of years)
measured seismic activity (~100 years of data)
distribution of earthquake activity on a both a global and local scale

7. Data for U.S. Earthquakes

8. VII. Earthquake Mitigation
C. Earthquake prediction
Long-term forecasting (probabilities of future fault slip)
Fault mapping
Understanding the distribution of faults and linkage of faults together in a fault system
Faults in red active during last 4 million years

9. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake prediction
Long-term forecasting (probabilities of future fault slip)
Pre-historical records
Geologic investigations; using the “rock record” to build a history of earthquake activity
Field of study called paleo-seismology

10. Reading the geologic record of past events
Paleo-seismology

11. Paleo-seismic study in sediments of a fault sag pond

12. Paleo-seismic study in sediments of a fault sag pond

13. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake prediction
Long-term forecasting (probabilities of future fault slip)
Based on past behavior
Historical records + pre-historical records + fault mapping = total record
Recurrence Intervals (Frequency - are we over due?)
Seismic Gaps (Is a fault segment overdue?)

14. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake prediction
Long-term forecasting (probabilities of future fault slip)
Seismic Gaps (Is a segment of a fault overdue?)
pre-1989 seismic record of San Andreas fault
1989 Loma Prieta earthquake and aftershocks
Source: USGS

15. VII. Earthquake Mitigation
Approach to earthquake mitigation
Hazard Identification and Risk Assessment
Earthquake prediction
Short-term warnings
Radio transmissions faster than seismic waves
Potential to
Shutdown public transport such as trains
Shutoff gas pipelines
Warn rescuers of aftershocks
Tsunami warnings
Use cell phone applications to warn individuals

16. VII. Earthquake Mitigation
D. Engineering and Building Codes
“Earthquakes don’t kill people buildings do”
If survivability is the goal, then engineering approaches and building codes are the main solution
Reinforced buildings and bridges in earthquake prone areas
Identify problem soils and avoid them, anchor foundations in bedrock or use foundation isolators
Avoid building sites in areas prone to landslides
Images: NOAA

17. VII. Earthquake Mitigation
D. Engineering and Building Codes
“Earthquakes don’t kill people buildings do”
Engineering approaches and building codes require that we know…
site specific risk levels for ground shaking, including enhanced shaking (think shake hazard maps)
response of buildings (of varying design) to ground shaking, requires monitoring shaking in buildings during earthquakes
consider also survivability of occupants vs. survivability of the building for future use (and how much you are willing to spend)

18. VII. Earthquake Mitigation
D. Engineering and Building Codes
“Earthquakes don’t kill people buildings do”
Engineering approaches and building codes require that we know…
site specific risk levels for ground shaking, including enhanced shaking (think shake hazard maps)
response of buildings (of varying design) to ground shaking, requires monitoring shaking in buildings during earthquakes
consider also survivability of occupants vs. survivability of the building for future use (and how much you are willing to spend)

19. VII. Earthquake Mitigation
E. Preparation in earthquake prone areas
Emergency preparedness and training is essential to surviving an earthquake
Coordination among emergency response agencies
Fire, utilities, police, rescue, medical, public transportation
Coordinate communications among emergency response teams and agencies
Practice exercises – The Great Shake Out
Full scale mock earthquake response exercises
Decentralize emergency supplies and equipment
Earthquake preparation in homes

20. VII. Earthquake Mitigation
E. Preparation in earthquake prone areas
ShakeMap – Real time shaking intensity map product from USGS
Computer generated shake map (intensity) for a real earthquake generated automatically in real time
Allows emergency first responders to be directed to areas with greatest needs without waiting for emergency calls and first hand on the ground accounts