Seismic Wave - Notation


The path that a wave takes between the focus and the observation point is often drawn as a ray diagram. An example of this is shown in a figure above. When reflections are taken into account there are an infinite number of paths that a wave can take. Each path is denoted by a set of letters that describe the trajectory and phase through the Earth. In general an upper case denotes a transmitted wave and a lower case denotes a reflected wave. The two exceptions to this seem to be "g" and "n". The notation is taken from and.

c the wave reflects off the outer core
d a wave that has been reflected off a discontinuity at depth d
g a wave that only travels through the crust
i a wave that reflects off the inner core
I a P-wave in the inner core
h a reflection off a discontinuity in the inner core
J an S wave in the inner core
K a P-wave in the outer core
L a Love wave sometimes called LT-Wave (Both caps, while an Lt is different)
n a wave that travels along the boundary between the crust and mantle
P a P wave in the mantle
p a P wave ascending to the surface from the focus
R a Rayleigh wave
S an S wave in the mantle
s an S wave ascending to the surface from the focus
w the wave reflects off the bottom of the ocean
No letter is used when the wave reflects off of the surface

For example:

  • ScP is a wave that begins traveling towards the center of the Earth as an S wave. Upon reaching the outer core the wave reflects as a P wave.
  • sPKIKP is a wave path that begins traveling towards the surface as an S-wave. At the surface it reflects as a P-wave. The P-wave then travels through the outer core, the inner core, the outer core, and the mantle.

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