Researchers dubbed this newly discovered phenomenon a "stormquake."
It's easy to see the impact an off-coast storm has on the water's surface. But according to a new study, severe storms can actually shake the ocean floor as well, causing "stormquakes" — a previously unknown phenomena that solves a seismic mystery.
Scientists already knew prior to this study that the ocean produces seismic signals. But while some of those signals could be explained by the ocean's waves, there was a band of signals that occurred at a frequency between 0.02 and 0.05 hertz that were seemingly inexplicable.
It was those signals that the U.S.-based researchers behind this new study, which was published in the journal Geophysical Research Letters on Monday, sought to explain — and after analyzing nearly 10 years' worth of seismic data, they noticed a strange pattern emerging.
"[The signals] were seasonal," researcher Wenyuan Fan told Science News. "Earthquakes do not have seasonality. But weather does."
That led the team to the discovery that the shaking of the ocean floor coincided with the raging of a storm above it.
However, a storm alone isn't enough to cause a stormquake — the seafloor below the storm has to be just the right shape, too.
"It's something about the shape — or the bathymetry — of the seafloor interacting with these big ocean waves that are produced during storms," researcher Wendy Bohon told Motherboard. "You're getting some kind of energy relief that's beating on the seafloor in a particular way, and those waves are moving out in all directions as coherent packages which we’re then able to detect using seismometers."
READ MORE: Scientists Discover a New Phenomena Called 'Stormquakes' [Motherboard]
More on earthquakes: This "Peeling" Tectonic Plate Could Cause Catastrophic Earthquakes