By I. Hansana, Jadetimes News
Researchers at Brown University have introduced a novel perspective on the origins of earthquakes, challenging longstanding beliefs about the primary causes of seismic activity. Published in the journal Nature, their study underscores the significant role of fault network geometry in determining the occurrence and intensity of earthquakes.
Traditionally, geophysicists have attributed earthquakes to the type of friction at fault lines, where stress accumulation leads to rapid slippage, known as stick slip behavior, releasing built up pressure. This unstable friction was thought to cause intense ground motions and earthquakes, while stable friction facilitated a smoother, creep like movement of tectonic plates without seismic events.
However, the Brown University team, led by geophysicist Victor Tsai, suggests that the geometric alignment of fault networks plays a crucial role in earthquake genesis. Their research indicates that the structural complexities of fault zones, including bends, gaps, and stepovers, might be more predictive of seismic activity than frictional properties alone.
The study employs mathematical modeling and analysis of fault zones in California, utilizing data from the U.S. Geological Survey's Quaternary Fault Database and the California Geological Survey. Tsai and his colleagues, including graduate student Jaeseok Lee and geophysicist Greg Hirth, liken fault interactions to the serrated edge of a saw.
Faults with simpler, less jagged structures allow for smoother, creep like movement, whereas more complex and jagged structures tend to catch and build pressure, eventually leading to an earthquake.
This new understanding of fault geometry's impact on seismic activity has significant implications for earthquake prediction and risk assessment, potentially improving current models and aiding in the anticipation of damaging earthquakes.
