Hurricanes are known to produce strong seismic waves all by themselves. Indeed, says Smithsonian‘s Surprising Science blog, Hurricane Sandy “generated seismic shaking as far away as Seattle.” But hurricane-triggered seismic waves these were not. These were real aftershocks. “Scientists did not initially notice the unusual pattern, Peng said, because the aftershocks were small (many below magnitude 2) and the hurricane itself produced a lot of seismic noise.” A careful analysis of the data, however, revealed that the aftershock activity actually rose around the time of the hurricane’s passing.
The scientists, says Nature, argue that “a decrease in pressure caused by the storm’s travel up the East Coast might have reduced forces on the fault enough to allow it to slip.” More research will be needed to definitively pin down the proposed tie between the hurricane and the earthquake. But the suggestion that the Virginia fault system would have been susceptible to the stresses caused by the hurricane aligns well with the idea that big natural systems, sometimes treated as if they act independently of the world around them, might actually all be connected.