A new analysis of seismic data from western Canada reveals that while most earthquakes triggered by fracking are preceded by smaller tremors, these foreshocks aren’t always reliable predictors of larger events. Bei Wang, a geophysicist at Zhejiang University of Technology in Hangzhou, China, and his colleagues analyzed ten years of data to reach their conclusions.
Researchers report in *Science* that 92 percent of earthquakes induced by fracking were preceded by foreshocks. The team examined approximately 70,000 earthquakes recorded in Alberta’s Western Canada Sedimentary Basin between 2014 and 2024, identifying 77 mainshocks of at least magnitude 3 linked to fracking. They then searched for foreshocks – smaller quakes occurring within 5 kilometers and five days of each mainshock.
Despite the high percentage of foreshock occurrences, the study highlights significant uncertainties. The team notes that 8 percent of the time, a damaging quake occurs without any preceding warning. Furthermore, even when foreshocks are present, their consistency varies greatly, ranging from a single tremor to as many as 700 tiny quakes. This inconsistency creates challenges for regulatory agencies employing a “traffic-light protocol” to manage seismic hazards.
Ryan Schultz, a seismologist at ETH Zurich who was not involved in the study, explained that the findings mean operators often receive a yellow light warning, giving them time to halt fluid injection. However, the lack of understanding of what causes foreshocks and how reliably they indicate a larger quake leads to both false positives and false negatives in earthquake predictions. A 2015 study first demonstrated that fracking triggered earthquakes in Ohio, and subsequent research has confirmed that activities involving fluid injection – including fracking, enhanced geothermal energy, and wastewater disposal – can induce seismic activity. A magnitude 5.6 quake in 2022 near Peace River, Canada, was initiated by wastewater injection during oil extraction.
Read the original coverage
💬 Comments
📜 Comment Policy