Scientists have developed a new technique for examining faults that could enhance earthquake predictions, providing insights into the origins of quakes, their propagation, and potential impacts.
Scientists have developed a new technique for examining faults that could enhance earthquake predictions, providing insights into the origins of quakes, their propagation, and potential impacts.
A study published in the journal Geology introduces this method, which aids in identifying the sources and pathways of past earthquake ruptures. This information is crucial for creating models for future earthquakes on significant faults.
Researchers analyzed fine, curved scratches left on fault surfaces after quakes, akin to tire marks from a drag race, to establish the direction from which the earthquake originated.
“Fault planes collect these curved scratch marks, which we had not previously considered or learned to interpret,” said UC Riverside geologist and lead author of the paper, Nic Barth.
These curved scratches have been noted on fault surfaces following several significant historical ruptures, including the 2019 Ridgecrest earthquakes in California. Computer simulations confirmed that the curvature shape reflects the earthquake’s originating direction.
This research is the first to show that this technique can be used to trace the locations of ancient earthquakes. It can be utilized on faults around the globe, aiding in predicting the potential impacts of future seismic events and improving worldwide hazard assessments.
“The scratches indicate both the direction and source of a previous earthquake, potentially providing clues about where a future quake may begin and how it will propagate. This is crucial for California, as understanding the direction of quakes on faults like San Andreas or San Jacinto could lead to more precise impact forecasts,” Barth explained.
The emergence point of an earthquake and its path can significantly affect the shaking intensity and the time delay before the tremors are felt. For instance, research has indicated that a large quake starting on the San Andreas fault near the Salton Sea and moving north will funnel more destructive energy towards the Los Angeles area than a nearby San Andreas quake moving away from LA.
On a positive note, if such an earthquake begins farther away, cellular alert systems could potentially give residents of Los Angeles about a minute’s warning before the shaking begins, potentially saving lives.
New Zealand’s Alpine Fault is noted for the regularity of its large earthquakes, making it an ideal subject for studying fault dynamics. The fault has had eruptions approximately every 250 years, almost like clockwork.
This research yields two key insights about the Alpine Fault. First, it confirmed that the latest quake in 1717 originated from the south and moved north, a scenario that could cause more significant shaking in populated areas. Second, it established that major earthquakes could start from either end of the fault, which was unknown before.
“We can now apply the techniques and knowledge we’ve gained from studying the Alpine Fault to investigate faults globally. Given the high likelihood of a significant earthquake occurring in Southern California soon, searching for these curved scratches on the San Andreas fault is a clear priority,” Barth stated.
Ultimately, Barth and his team aspire for earthquake researchers worldwide to adopt this innovative technique to uncover the historical patterns of their local faults. Barth is particularly keen on utilizing this approach across California’s fault systems, including the infamous San Andreas Fault, to enhance predictions and preparedness in one of the most seismically active regions in the United States.
“This newfound knowledge will undoubtedly improve our understanding and modeling of earthquake behavior, both in California and worldwide,” he concluded.