quake vocab

  1. Determining the location of the focus
    • Body waves (goes through the body of the earth): *P-waves travel faster the S-waves, so they arrive before
    • -measure arrival of P & S waves=distance from the epicenter to the station
    • -primary and secondary
  2. Why can't moderate-sized earthquakes relieve the stress and thus, prevent a great earthquake?
    • -it would take about 1,000 quakes to release the amount of energy of an M=7 quake. (1 increase in magnitude results in an increase of about 31 times in the energy released)
    • -loma Prieta quake did very little to relieve the stress build-up in the rocks in the San Francisco area as it builds toward "The Big One"--the quake of a magnitude similar to the 1906 San Fran quake which is expected w/in the next 30 yrs
  3. Characteristics of Magnitude
    • 1) longer length of rupture,larger magnitude
    • 2)More Offset, larger magnitude
    • 3)Larger Magnitude, longer shaking
  4. Alaska-Seismic risk zone
    • -2nd largest earthquake ever recorded 1964
    • -8.3 magnitude
    • -3-4 minutes
    • -11 aftershocks of magnitude greater than 6.0
    • -caused vertical displacement
    • -produced a tsunami
Card Set
quake vocab
geo final