A team of researchers has made a groundbreaking discovery in California’s Sierra Nevada mountains, finding deep earthquake activity beneath the surface that challenges current understanding of how continents form and operate.
Seismologist Deborah Kilb, who analyzed decades of seismic data, noticed a series of deep earthquakes occurring under the mountain range at depths where the Earth’s crust is typically too hot and high pressure for seismic activity. The earthquakes were up to twice as deep as usual and appeared to be ongoing in some areas.
The researchers found that the deep earthquakes are linked to a process called lithospheric foundering, which occurs when the Earth’s crust is pulled down and thinned by plate tectonics. This process can cause the crust to deform and create faults, resulting in earthquakes.
Lead researcher Dr. Schulte-Pelkum explained that the process is similar to squeezing clay between hands, where spots of different colored clay turn into stripes. She also noted that the deep earthquakes are caused by the Earth’s crust being pulled down by hot mantle material, which takes time for the rock to warm up or cool down.
The study provides evidence that lithospheric foundering has occurred in other mountain ranges around the world, including the Andes in South America. The researchers believe that further studies in this area could help scientists better understand how the Earth evolves on long timescales and potentially improve earthquake forecasting.
Dr. McMillan, a research geologist not involved in the study, noted that the discovery highlights the importance of tying together different datasets to gain a deeper understanding of geological processes. He also emphasized that further research is needed to fully comprehend the effects of lithospheric foundering on earthquakes and the planet’s evolution.
The study’s findings have significant implications for our understanding of the Earth’s surface and the processes that shape it. By exploring the deep Earth, scientists can gain insights into the planet’s history, its potential for future natural disasters, and the intricate relationships between different geological phenomena.
Source: https://edition.cnn.com/2025/04/18/science/lithospheric-foundering-earth-peeling-sierra-nevada/index.html