Earthquake Hazard: Ground Shaking

ground shakes
buildings and things inside may fall
1556 Shaanxi province, china
- worst recorded earthquake for fatalities
- housing was silt (very fine-grained sediment) caves, most collapsed
- 883,000 people died
buildings on solid rock or compacted sediments are safer
wet, loose sediment and artificial fill have longer and more intense shaking
- also prone to liquefaction
shaking can trigger resonance in a building
- amplitude of the wave increases when the frequency of the seismic wave is the same or very close to the natural frequency of the building
hypocenter: point on the fault where motion starts
epicenter: directly above hypocenter on surface
when the ground shakes, it creates a fault scarp
- fault scarp: exposure of the fault visible at the surface; exposed due to offset (movement) along the fault
elastic rebound theory: explains how energy builds up and is then released in an earthquake and how that energy is released
- this can create ground shaking