Earthquake Effects

Earthquake Effects

Primary Effects

• Short periods of intense ground motion
  • Can damage human structures
  • “Earthquakes don’t kill people, buildings kill people”
• A few factors determine the amount and intensity of damage done
  • Key factor of intensity of damage is the earthquake’s magnitude
  • Length is also important (larger earthquakes tend to be longer)
  • How buildings are structured and constructed
  • Surface materials on which structures are built
  • Structures on loose/sedimentary materials usually experience more intense shaking
  • Structures on solid rock are generally more stable
  • Some structures can be engineered specifically to mitigate earthquake damage

Secondary Effects

• Other processes related to the shaking
• Mountainous areas → landslides (loose rocks/soil break free)
• Wet, low-lying areas → liquefaction (wet soils liquify)
  • Especially common in areas of sandy soils
• Ground cracking
• Fire
  • Shaking may break gas lines, which catch fire
  • Eg. 1906 San Francisco earthquake → wooden buildings survived quake but not fire
• Tsunamis
  • Fault movements displace water above the fault
  • Waves radiate from epicenter
  • Not overly noticeable in middle of ocean, but can wreck coastal areas
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