Scientists have uncovered a new geophysical phenomenon where a hurricane or other strong storm can spark seismic events in the nearby ocean as strong as a 3.5 magnitude earthquake.
According to Florida State University researcher Wenyuan Fan, an assistant professor of Earth, Ocean and Atmospheric Science:
“We’re calling them ‘stormquakes.’ This involves coupling of the atmosphere-ocean and solid earth. During a storm season, hurricanes or nor’easters transfer energy into the ocean as strong ocean waves, and the waves interact with the solid earth producing intense seismic source activity.”
Fan was the lead author of a scientific paper on this phenomenon. Researchers from Woods Hole Oceanographic Institution as well as Scripps Institution of Oceanography and the U.S. Geological Survey contributed to it.
Fan and his colleagues analyzed nearly 10 years’ worth of seismic and oceanographic records from September 2006 to February 2019 and found connections between strong storms and intense seismic activity near the edge of continental shelves or ocean banks.
Specifically, researchers found evidence of more than 10,000 stormquakes from 2006 to 2019 offshore of New England, Florida and in the Gulf of Mexico in the United States, as well as offshore of Nova Scotia, Newfoundland and British Columbia in Canada.
“We can have seismic sources in the ocean just like earthquakes within the crust. The exciting part is seismic sources caused by hurricanes can last from hours to days.”
Not all hurricanes cause stormquakes, however. There are hotspots. Scientists couldn’t find evidence of stormquakes off of Mexico or from New Jersey to Georgia in the United States. Even Hurricane Sandy, one of the costliest storms on record in the United States, did not spur stormquakes.
This could mean that stormquakes are strongly influenced by the local oceanographic features and seafloor topography, according to Fan:
“We have lots of unknowns. We weren’t even aware of the existence of the natural phenomenon. It really highlights the richness of the seismic wave field and suggests we are reaching a new level of understanding of seismic waves.”
Check out Fan’s and his colleagues’ research in the journal Geophysical Research Letters.