For years, scientists have been trying to track an extremely rare “boomerang” earthquake. Now, for the first time ever, they’ve recorded an image under the ocean – and it’s even more bizarre than they expected.
Earthquakes are the result of broken rock on a fault, the boundary between two plates. A “boomerang” earthquake, also known as a “backward propagation ultrasonic crack,” means the fracture comes out of the original crack before returning to it at full speed, the scientists say. faster.
Bigis capable of destroying buildings and causing tsunamis, so understanding how they work is essential to assessing potential hazards and implementing warning systems for earthquakes during future.
According to a new study in the journal Nature Geoscience, a group, led by scientists from the University of Southampton and Royal University London, successfully recorded a magnitude 7.1earthquake on May 29. August 2016. It runs along the Romanche Fault Zone, a 560-mile earthquake in the near equatorial Atlantic, between Brazil and Africa.
Scientists say that large earthquakes – that is 7 or more rich – are difficult to study because they often cause a series of chain reactions along a complex network of faults. The sub-ocean faults have a simple shape but are located far from the terrestrial seismic network, so an underwater seismic network is required.
The quake moved in one direction between the South American and African tectonic plates, then returned to its starting point at lightning speed – breaking the “seismic sound barrier,” researchers say. “- a kind of booming sound.
An analysis shows that the earthquake has two different phases. The rupture goes up and east first, before abruptly reversing and returning west to the center of the fault at a speed of 3.7 miles per second.
Scientists aren’t sure exactly how this happened, but they believe the first phase has somehow triggered its more active counterpart.
Only a handful of boomerang earthquakes have ever been recorded – mainly theoretical, so far.
“While scientists discover that such reverse fault mechanisms could occur from theoretical models, our new study provides some of the clearest evidence for the mysterious mechanism. this happened in a real error, “led Dr. Stephen Hicks, from the Department of Earth Science. and Engineering at Imperial College London, said in a press release.
“Although the fault structure looks simple, how the earthquake evolved, and this is quite the opposite of how we predicted the earthquake before we started analyzing the data.”
If a similar kind of earthquake happens on land, it would severely affect the amount of ground shake – and possibly expand the area affected, scientists say. Successfully tracking more boomerang earthquakes will allow researchers to better predict and evaluate hazards from such events, improving impact forecasting.