2. Before you jump into this slide show, you should view the Presentation on EarthquakeSeismology See notes for link.

3. Earthquake Intensity is what you feel. What controls ground shaking and earthquake damage? Magnitude — More energy released by larger earthquake Distance — Shaking decreases with distance Geology — Local geology can amplify the shaking Building style — Strength and building design Duration of shaking — Increases with earthquake magnitude Example: 1994 Northridge EQ, M=6.7

4. Seismic intensity is affected by rock type. Amplitude of oscillation How would you expect the houses to react during an EQ?

5. Seismic intensity is affected by rock type. Amplitude of oscillation increasing

6. Amplification of Ground Motion

7. Damage from Loma Prieta EQ 1989 West of Oakland. Marina District of San Francisco. Santa Cruz.

8. Landslides El Salvador January 2001 M7.6

9. Liquefaction experiment What happens to a structure built on a weak foundation when an earthquake strikes? Photos: Lily Rodriguez From website below For the description of this liquefaction activity: http://www.exploratorium.edu/faultline/activezone/liquefac tion.html Niigata, Japan 1964 Source: National Geophysical Data Center

10. Building design: If the resonant frequency of a building is equal to the frequency of ground oscillation, then damage or collapse is likely. What is resonant frequency? Discussion: Why is building damage selective?

11. Resonance Oscillating buildings demonstration—3 methods. BOSS model Links to video demonstrations by John Lahr are in notes. Two similar demonstrations use simpler methods: Spaghetti & Manilla file raisins……. “Boss lite”…

12. During earthquakes, buildings experience vertical AND horizontal accelerations. NOT a simple problem to engineer earthquake resistance.. BUT can be done. “Earthquakes don’t kill people. Buildings that collapse during earthquakes kill people.”

13. Building design is critical to earthquake safety Resistance to shear is critical. See the video lecture on Building Strength available through link provided in Notes.

14. Seismic Retrofit 1942 North Portland House Wood frame NOT attached to foundation.

15. Seismic Retrofit Bolting frame to foundation on exterior.

16. Seismic Retrofit Post & beam reinforcement.

17. Base Isolation