The Bullen discontinuity is a boundary within the Earth's lower mantle that is marked by an abrupt change in seismic wave velocities. It is named after Australian seismologist Harold Jeffreys Bullen.
The Bullen discontinuity is a boundary within the Earth's lower mantle that is marked by an abrupt change in seismic wave velocities. It is named after Australian seismologist Harold Jeffreys Bullen.