1. 8.3 Destruction from Earthquakes
Seismic Vibrations (Shaking)
8.3 Destruction from Earthquakes
Damage from earthquake waves depends on:
Intensity & duration of vibrations
Material on which the structure is built
The design of the structure

2. 8.3 Destruction from Earthquakes
Seismic Vibrations
8.3 Destruction from Earthquakes
 Building Design
• Factors that determine structural damage
- Steel is better than stone or brick
- Material under structure: sands are the worst

3. Earthquake Design

4. 8.3 Destruction from Earthquakes
Seismic Vibrations
8.3 Destruction from Earthquakes
 Liquefaction
• Saturated soil material turns fluid
• Underground objects may float to surface

5. 8.3 Destruction from Earthquakes
Tsunamis
 Cause of Tsunamis
• Vibration of a quake sets an underwater landslide into motion
• Tsunami is the Japanese word for “seismic sea wave.”

6. 8.3 Destruction from Earthquakes
Other Dangers
8.3 Destruction from Earthquakes
 Landslides
• Greatest damage to structures is from landslides and ground subsidence
 Fire
• In the San Francisco earthquake of 1906, most of the destruction was caused by fires that started when gas and electrical lines were cut.

7. Landslide Damage

8. Fire Resulting from an Earthquake

9. Predicting Earthquakes
Short/long-range predictions not yet successful.