Researchers studying earthquakes in California have identified a rare geological process deep beneath the Sierra Nevada mountain range, known as lithospheric foundering. This phenomenon involves the Earth’s outer layer detaching and sinking into the mantle below.
According to seismologist Deborah Kilb, unusual patterns in earthquake data revealed quakes occurring at depths of 20-40 kilometers in central regions of the Sierra Nevada. Her findings sparked collaboration with geophysicist Vera Schulte-Pelkum, who was examining unusual rock deformations in the same area.
Their analysis using seismic imaging techniques confirmed that the lithosphere is actively peeling away beneath the Sierra Nevada, a process previously only theorized in this region. The findings suggest that the central Sierra is undergoing lithospheric foundering, while the northern part of the range has yet to show signs of such activity.
The process is driven by density differences in Earth’s layers. As Schulte-Pelkum explained, removing dense material from the lower layer allows lighter crustal layers to remain at the surface. Seismic images revealed a distinct layer about 40-70 kilometers deep within the mantle, showing characteristics that gradually shift as one moves northward.
The discovery may offer insight into the formation of continental crust and the evolution of continents. Lithospheric foundering is believed to play a role in creating land masses by leaving lasting geological fingerprints. While this process is extremely slow and invisible from the surface, it can shape the Earth’s surface over immense timescales.
Source: https://dailygalaxy.com/2025/04/geologists-detect-alarming-signs-of-earths-crust-peeling-under-sierra-nevada-and-its-still-moving