Seismology and Rebound Theory

Seismology

• seism: shaking or earthquake

  • from the greek “seismos”

• ology: study

• seismology: the study of earthquakes

• hypocenter: point on the fault where the motion starts

• epicenter: directly above the hypocenter on the surface

• fault scarp: exposure of the fault visible on the surface, exposed due to offsets (movement) along the fault

Elastic Rebound Theory

• explains how energy builds up and then is released in an earthquake, and how that energy is released

  1. fault between 2 blocks is locked

     1. a pre-existing fault is held stationary (locked) due to friction

  2. pressure builds up

     1. if the two blocs are under stress (any type), pressure builds up

  3. movement occurs

     1. when stress is high enough, friction is overcome and movement occurs where stored energy is released (seismic waves-shaking) and an earthquake occurs

  4. blocks move

     1. the two blocks have moved relative to one another and each block returns to its undeformed shape

Consequences of Elastic Rebound Theory

• faults store energy slowly

  • over decades to centuries to millenia

• release energy rapidly in an earthquake

  • 10s of seconds or less