Researchers at Brown University have uncovered new insights that challenge long-held beliefs about the causes of earthquakes. By examining the geometric structure of rocks at earthquake origins, their study reveals that fault network alignment plays a crucial role in determining the location and intensity of earthquakes. This finding contradicts the traditional view that friction at faults is the primary factor.
Published in the journal *Nature*, the research suggests that the geometry of fault networks, including features like bends, gaps, and stepovers, is more influential than previously thought. “Our paper paints a very different picture about why earthquakes happen,” said Victor Tsai, a lead author and Brown geophysicist. This new perspective has significant implications for predicting earthquake locations and their potential damage.
Traditionally, geophysicists believed that earthquakes occur when stress at fault lines builds up and causes the faults to slip rapidly, a process known as stick-slip behavior. It was thought that unstable friction at faults led to earthquakes, while stable friction allowed for slow, creep-like movements without earthquakes. Tsai explains that researchers have long tried to measure these frictional properties to predict earthquake occurrences.
However, the new study, based on mathematical modeling and data from California’s fault zones, indicates that the complex geometry of faults may be more relevant. For example, faults with smooth, fewer serrated teeth allow rocks to slide past each other smoothly, leading to creep. In contrast, jagged, complex fault structures catch and build pressure, eventually causing earthquakes when they break free.
The research team, including Brown graduate student Jaeseok Lee and geophysicist Greg Hirth, utilized data from the U.S. Geological Survey’s Quaternary Fault Database and the California Geological Survey to support their findings. This groundbreaking work enhances our understanding of earthquake mechanics and could lead to better prediction and preparation for seismic events.
