Inner core differential rotation (1)

• Inner core anisotropy anisotropy axis

• anisotropy axis parallel to Earth rotation axis

• seismic travel time see anisotropy axis ,

  • at time t0, seismic travel time see anisotropy axis at one position p0,
  • at time t1, seismic travel time see anisotropy axis at one position p1,
  • etc...

• from time variation of the position of the anisotropy axis: inner core differential rotation