The female scientist who discovered the core of the Earth

Danish seismologist Inge Lehmann (1888-1993) is best known for presenting the first evidence of the Earth’s inner core in 1936. Her active research career as a seismologist began in 1928, continued well into the 1970s, and earned her the reputation as “The Grande Dame” of modern seismology.

Born at a time when few women held senior scientific positions, Lehmann had an extraordinary career. In 1928, she was appointed head of the Seismic Section at the Danish Geodetic Institute, where she published evidence for the existence of the Earth’s solid inner core in 1936. After her retirement in 1953, she continued her work at research institutions in the USA, and in 1964, she proved a velocity discontinuity at a depth of 200 km, known today as the “Lehmann Discontinuity”.

During Lehmann’s lifetime, seismology, the study of earthquakes and propagation of elastic waves through the Earth, developed from a small, isolated discipline to a large, well-funded research area. This growth took place against the backdrop of the Cold War with its political and military agendas. Seismology attracted special interest because it provided tools for the detection of nuclear weapons tests.

Lehmann’s career can therefore be contextualised into a wider framework of discipline development, international politics, and gender studies. By taking a biographical approach to her life and career, in the form of a book, it is possible to reveal the much larger story of how international seismology developed from a small, obscure discipline to a science with powerful geopolitical implications.