1. San Francisco Earthquake 1989 Loma Prieta

2. What happened? October 17 th 1989 5.04pm 20 seconds duration Magnitude 7 Intensity IX Enormous amounts of damage

3. Damages Cost $10 billion –$2 billion in San Francisco Damages –18000 homes –2500 other buildings Destroyed –963 homes –147 other buildings

4. Casualties Over 3700 injuries 62 deaths 12000 missing

5. Catastrophic Events Collapse of the Interstate 880

6. Collapse of the San Francisco-Oakland Bay bridge

7. Liquefaction –Building collapse in Marina District

8. Landslides Damage to Epicentre locality

9. Cause San Andreas Fault – Plate Boundary – 800 miles across California

10. Unusual San Andreas activity –Horizontal Slip –Thrusting Result 70° dip to southwest

11. Earthquake History Long history of earthquakes –First recorded quake in 1769 –1989 quake repeat of 1865 –First large earthquake since 1906 Irregular pattern to earthquakes –Many in one year (e.g. 1971) –Then no significant ones for several years

12. Prediction Earthquake was predicted –Little significant activity –Several over 5 in last 2 years

13. Damage Prevention Earthquake Research Improved building design –Reinforcements –Less rigid –Movement Very costly –Cant rebuild whole city Research is never complete –Full prevention can never occur