A new study has unraveled the hidden mechanisms behind earthquake formation, shedding light on the mysterious transition from quiet, gradual motion to the violent ruptures that shake the Earth.

Using cutting-edge experiments and innovative models, research shows that a slow, silent release of stress is a prelude to and a necessary trigger for seismic activity. By incorporating the overlooked role of fault geometry, the study challenges long-held beliefs and offers a new perspective on how and when earthquakes begin.

These findings not only deepen our understanding of nature’s most powerful forces, but also pave the way for improved predictions of seismic events.

Researchers from the Racah Institute of Physics at the Hebrew University of Jerusalem led by Prof. Jay Fineberg and Ph.D. Student Shahar Gvirtzman, in collaboration with Prof. David S. Kammer from ETH Zurich and Prof. Mokhtar Adda-Bedia from École Normale Supérieure de Lyon, has gained groundbreaking insights into the mechanisms that drive frictional cracks and the formation of earthquakes.

Your study, which appears in Naturefills critical gaps in our understanding of the transition from slow, aseismic motion to rapid seismic rupture.

The team conducted experiments and developed theoretical models to show how slow, steady creep at stress thresholds transitions into the dynamic rupture associated with earthquakes. By extending the principles of fracture mechanics, the researchers took into account the finite width of fault interfaces, a factor often overlooked in traditional models.

“Our results challenge and refine conventional models of fracture dynamics,” explained Prof. Fineberg. “We show that slow, aseismic processes are a prerequisite for seismic ruptures caused by local stresses and geometric constraints. This has profound implications for understanding when and how earthquakes begin.”

Key highlights of the study include groundbreaking experimental validation, where researchers used high-speed imaging and innovative methods to observe how fracture nucleation begins.

Their results show that the process begins as small, slow-moving two-dimensional patches of frictional motion. These patches gradually expand and eventually transition to the rapid dynamics traditionally described by classical fracture mechanics, representing a significant leap in our understanding of this phenomenon.

The study also highlights the crucial role of geometric transitions in controlling nucleation dynamics. By incorporating the finite width of fault interfaces into their models, the researchers challenged and refined existing theories of earthquake formation.

This focus on the geometric properties of faults provides new insights into the structural and mechanical factors that influence the onset of seismic activity.

In addition, the research has far-reaching practical applications. The newly developed framework also provides a deeper understanding of important everyday processes of both friction and material fracture. Additionally, the new framework highlights the importance of slow, aseismic processes that often precede earthquakes.

Even seemingly “quiet” seismic precursors that may have been previously overlooked could contain important information about upcoming seismic events. This discovery has the potential to support predictive models and improve our ability to predict and mitigate earthquake risks.

The implications of the study extend beyond earthquake science and provide insights into material strength, fracture dynamics, and the development of predictive models for seismic activity.