Powerful hurricanes that create oceanic storms might have a new category, under circumstances where wave energy stakes the seafloor with great ferocity. When the force is sufficiently powerful, this could produce a new type of quake: stormquake.
The presence of stormquakes has been identified by Dr. Wenyuan Fan of Florida State University. His research group has characterized a new type of interaction between Earth’s atmosphere, ocean and crust.
What are stormquakes?
It’s perhaps easier to begin by saying what stormaquakes are not. Stormquakes are different to earthquakes, with an earthquake being triggered by subsurface shifting within the solid Earth. In contrast, stormquakes are ocean waves thrown up by especially powerful hurricanes (or Nor’easters, description of a storm along the East Coast of North America). The weather events naturally produce waves and these waves then “interact” in some places with solid earth under the sea to cause intense seismic source activity. Hence, under special conditions, the constant sloshing of ocean waves produces seismic waves. These waves have an acoustic signal, producing high-frequency signals called microseisms (a faint earth tremor caused by natural phenomena).
Stormquakes are equivalent to an earthquake with a magnitude of 3.5, not so powerful on land but significant enough to whip up larger waves at sea.
How are stormquakes produced?
The stormquake is the product of long‐period ocean waves interacting with shallow seafloor features, located near the edge of continental shelves (or ocean banks).
To produce conclusive proof of the existence of stormquakes, the U.S. researchers analyzed ten years (2006–2015) of continuous vertical-component long-period 14 channel seismic data recorded by stations spanning the whole U.S. continent. Over this period, some 14,000 stormquakes were assessed.
These events only occurred during winter months. Given that earthquakes do not have seasonality, this aspect triggered Dr. Fan to launch is research project and to explore these newly identified weather events.
The analysis also found that major U.S. hurricanes had produced a high number of stormquakes. One example was Hurricane Bill, a storm that formed 10 years ago in the Atlantic Ocean, causing numerous seismic events.
Research significance
Stormquakes are not simply a new quake of interest. The researchers hope that by studying stormquakes, new information that can be used to investigate the Earth structure and ocean wave dynamic can be generated.
The use of such data extends from deciphering the Earth’s inner structure to tracking ocean or ice dynamics; and even monitoring the effects of climate change.
Research paper
The research has been published in the journal Geophysical Research Letters. The research paper is simply titled “Stormquakes.”
Essential Science
This article is part of Digital Journal’s regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue.
Last week we looked at the connection between inflammation and brain function. New research suggests there is a connection between the physiological state of the body and brain function.
The week before we examined a new study that shows how white noise can assist with certain types of hearing loss. This is evidenced by a continuous white noise background helping pure sounds to be perceived more precisely.
