Scientists discovered a phenomenon in which a strong storm causes seismic events in the seafloor – some of which are as strong as a magnitude 3.5 earthquake.
“We’re calling them ‘stormquakes,’ ” said Florida State University atmospheric scientist Wenyuan Fan, the lead author of a new study about them.
“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,” he said in a statement.
The shaking of the seafloor during a big storm can last for hours or even days, according to the study, which was published this week in the journal Geophysical Research Letters.
The quakes are fairly common, but they weren’t noticed before because they were considered seismic background noise. They aren’t dangerous.
“This is the last thing you need to worry about,” Fan said.
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Fan and his colleagues studied seismic and oceanographic records from 2006 to 2019 and found a connection between strong storms and intense seismic activity near the edges of continental shelves or ocean banks.
Researchers found evidence of more than 10,000 stormquakes during those years offshore of New England, Florida and in the Gulf of Mexico in the USA, as well as offshore of Nova Scotia, Newfoundland and British Columbia in Canada.
One example the researchers cited was Hurricane Bill, an Atlantic storm in 2009 that strengthened into a Category 4 hurricane and struck Newfoundland as a tropical storm. When the hurricane arrived, numerous seismic events were located off the New England and Nova Scotia coasts
The study said Hurricane Ike in 2008 and Hurricane Irene in 2011 also produced stormquakes.
There is still more to learn about stormquakes, Fan said.
“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,” he said.
Contributing: The Associated Press