In a first, scientists found evidence of a rare and unusual ‘boomerang’ earthquake that shook the deep seabed underneath the Atlantic Ocean in 2016.Also Read - Google Develops Android-Based Tool That Will Alert Smartphone Users Before Earthquake

Earthquakes occur when rocks suddenly break on a fault, but during a boomerang earthquake, the rupture initially spreads away from an initial break but then turns and runs back the other way at higher speeds.

Published in Nature Geoscience on Tuesday, a study was conducted by an international team of experts from the UK, the US, Germany, and Japan during which they examined the path one of these quakes under the Atlantic ocean.

Notably, a magnitude 7.1 earthquake in the Atlantic Ocean back in 2016 was supposedly one of these rare types of earthquakes. This earthquake took place along the Romanche fracture zone, which lies near the equator, roughly mid-way between the east coast of Brazil and the west coast of Africa.

Tracking the rupture along the fault, scientists observed that the rupture initially travelled in one direction. It then came back around for a second strike, bringing an increase of speed on the second strike by breaking the ‘seismic sound barrier’.

The team believe that the first phase of the rupture was crucial in causing the second, rapidly slipping phase.

”Whilst scientists have found that such a reversing rupture mechanism is possible from theoretical models, our new study provides some of the clearest evidence for this enigmatic mechanism occurring in a real fault,” Dr. Stephen Hicks, first author of the study, said in a statement.

”Even though the fault structure seems simple, the way the earthquake grew was not, and this was completely opposite to how we expected the earthquake to look before we started to analyze the data,” he added.

The researchers believe this phenomenon is quite rare and tracked in the ocean for the first time.

Such earthquakes may help scientists assess potential hazards better, and implement more efficient warning systems for them in future.