What is the Gutenberg discontinuity?

The Gutenberg discontinuity is the deep boundary separating Earth's solid lower mantle from its molten outer core, located approximately 2,900 kilometers below the surface. It was discovered through abrupt changes in seismic waves generated by earthquakes or explosions, specifically as primary waves drop in velocity and secondary waves vanish entirely. Named after seismologist Beno Gutenberg, this narrow and uneven zone plays a crucial role in Earth's thermal dynamics and magnetic field generation.

What we know

• The Gutenberg discontinuity lies at a depth of about 2,900 kilometers below Earth's surface, marking the core-mantle boundary. [1, 2, 3]
• At the Gutenberg discontinuity, primary seismic waves decrease in velocity while secondary seismic waves disappear completely because they cannot travel through liquids. [2, 3]
• The boundary is an uneven zone featuring undulations that are affected by mantle convection and fluid currents in the outer core. [2, 3]
• As Earth's interior slowly dissipates heat, the molten core gradually solidifies and shrinks, causing the boundary to slowly move deeper over time. [2] · medium confidence

Where to go next

• whoWho was Beno Gutenberg?
• how we knowHow do seismic waves reveal Earth's interior?
• compared withWhat is the Mohorovičić discontinuity?
• what followedHow is Earth's magnetic field generated?
• the bigger pictureWhat are Earth's interior layers?
• an unexpected connectionHow does the core-mantle boundary connect to earthquake magnitude scales?Beno Gutenberg, who is namesake to the core-mantle discontinuity, was also the close colleague and mentor of Charles Richter who jointly developed the Richter earthquake magnitude scale.

Sources

• [1]Gutenberg discontinuity (Wikidata Q1557147) · CC0 1.0
• [2]Gutenberg discontinuity · CC BY-SA 4.0
• [3]Core–mantle boundary · CC BY-SA 4.0
• [4]Mohorovičić discontinuity · CC BY-SA 4.0
• [5]Beno Gutenberg · CC BY-SA 4.0