Natural disasters come in all forms, but some are certainly more devastating than others. A small tornado that tears through an unpopulated countryside is less serious than a super-powerful hurricane that slams into large coastal communities, for example. Earthquakes and tsunamis are both natural phenomena that occur due to the stress that builds up between the tectonic plates that make up Earth’s crust, but new research suggests that our estimates for how dangerous these events can be are on the low end of realistic.
In a new study published in Nature Geoscience, researchers from The University of New Mexico and Nanyang Technological University provide evidence that so-called megathrust earthquakes beneath Earth’s oceans could be even more powerful than we think. It’s a complex but important bit of research that could help communities prepare for the worst of what an earthquake and tsunami can deliver. That is if the data is adopted and new safety measures put in place.
Earthquakes occur when there is a buildup of stress along the area where two of Earth’s plates meet. Due to friction, the plates don’t always move smoothly, and when a buildup of energy occurs, the release causes intense shaking. A megathrust earthquake occurs in an area called a subduction zone. Subduction zones are created when one of the tectonic plates slides beneath another. When the plates get stuck but are still moving toward each other, stress builds up. This is called a slip deficit, and it is eventually “paid” when the bottom plate slides violently beneath the top plate. When this happens in the ocean, it can generate a massive wave or tsunami.
Modeling and simulating this action can be difficult due to the complex way the plates interact where they meet. This area is called the fault, and what happens along the fault is ultimately what determines how intense an earthquake or resulting tsunami will be. The researchers behind this latest study used new models to account for the movement of the fault in areas where traditional observation using seismic instruments just isn’t possible.
“We applied this technique to the Cascadia and Japan subduction zones and found that wherever deeper locked patches are present, the shallow fault must also have a high slip deficit—regardless of its own frictional properties,” Eric Lindsey, who led the research, said in a statement. “If these areas can slip seismically, global tsunami hazard could be higher than currently recognized. Our method identifies critical locations where seafloor observations could yield information about frictional properties of these faults in order to better understand their slip behavior.”
Using this new model, researchers could investigate the true risks posed by other subduction zone faults around the world. If the danger is found to be significantly greater, new measures could (and should) be put in place to help mitigate the impact on coastal communities.