What is the name of the boundary between Earth’s mantle and liquid outer core?

The Gutenberg discontinuity is the boundary between Earth’s mantle and liquid outer core.

It lies at a depth of about 2,900 kilometres below Earth’s surface. At this boundary, solid silicate mantle gives way to the liquid iron-rich outer core, producing a major change in density and seismic-wave behaviour.

S-waves cannot pass through the liquid outer core, creating the well-known S-wave shadow zone. P-waves can enter the outer core, but they slow and refract strongly, producing a P-wave shadow zone as well.

The discontinuity is named after German geophysicist Beno Gutenberg, who helped use earthquake waves to investigate Earth’s interior. It is distinct from the Mohorovičić discontinuity, which separates the crust from the mantle.