Inge Lehmann
Inge Lehmann
Seismologist & Geophysicist
By: Gabriela Yáñez González
Inge Lehmann (1888-1993) was a Danish seismologist and geophysicist best known for her groundbreaking discovery of Earth’s inner core. Born in Copenhagen, she was educated in a progressive school, where girls and boys where boys and girls were treated exactly alike, which encouraged independent thinking and significantly shaped her scientific career. She later studied mathematics and physics at the University of Cambridge before working in actuarial science and eventually transitioning to seismology. Despite the challenges women faced in science at the time, she excelled academically and professionally, eventually becoming the head of the seismology Department at the Geodetical Institute of Denmark.
Major Accomplishments
Lehmann's most notable achievement came in 1936 when she analyzed seismic wave data and identified discrepancies in how P-waves (primary seismic waves) traveled through the Earth's interior. She proposed that rather than being entirely molten, as previously believed, the Earth's core had a solid inner section surrounded by a liquid outer core.
Lehmann is also known for researching Earth’s mantle. Her later work provided insights into the structure and properties of the Earth's crust and deeper layers. She noticed the existence of a region in Earth’s upper mantle in which seismic waves travel faster.
Two boundary regions, or discontinuities, are named for her: one Lehmann discontinuity occurs between Earth’s inner and outer core at a depth of roughly 5,100 km (about 3,200 miles), and the other occurs at a depth of approximately 200 km (about 120 miles) beneath Earth’s surface in the upper mantle.
Lehmann co-founded the Danish Geophysical Society (1936) and chaired the organization in 1941 and 1944.
She was awarded the William Bowie Medal of the American Geophysical Union in 1971 for her contributions to the field of geophysics.
She received the Medal of the Seismological Society of America in 1977.
Impact and Legacy
Her impact on geophysics extends beyond her scientific findings. She also paved the way for women in science, demonstrating perseverance in a male-dominated field. The American Geophysical Union created the Inge Lehmann Medal in her honor in 1995, and, starting in 1997, it was awarded to researchers displaying “outstanding contributions to the understanding of the structure, composition, and dynamics of the Earth’s mantle and core.” Also, a beetle species, Globicornis (Hadrotoma) ingelehmannae, was named in her honor in 2015. Her work remains fundamental to modern seismology, influencing everything from earthquake research to the study of planetary interiors in space exploration. Today, she is widely recognized as one of the most important figures in Earth sciences, and her legacy continues to inspire scientists worldwide.
