Readings from textbook
• Chapter 2 Earthquakes and From chapter 9 – Section on
Tsunami Pages 259 to 267
What exactly causes the damage?
• 1. Surface Faulting
o Structures on the fault will be disrupted by the tearing
o So don’t build right on ACTIVE faults
But people do! Eg. San Francisco, and other parts
of San Andreas fault
• 2. Ground Shaking
o this is generally the greatest threat to buildings and
o in a big earthquake, the shaking can be severe even
100’s ok kilometers away from the epicenter
o The amount of shaking also depends on the nature of
the soil/rocks in the area
Soft soils (eg. Clays ) shake more than ….
Stiff soils (eg sand) which skakes more than….
EG, Loma Prieta earthquake near San
EG. 1985 Earthquake near Acapulco, Mexico
• 1. The closer you are to the quake, the greater the damage …
• 2. The greater the magnitude of the quake, the greater the
But-> this is modified by natural and anthropogenic conditions
• Natural : nature of soils/rocks