Reconstructed image of the fracture zone.
For the first time, scientists have detected an extremely rare 'boomerang earthquake' under the Atlantic Ocean near the equator. According to the scientists, the boomerang earthquake is also known as a "back-propagating supershear rupture", is the fracture that travels away from the initial crack before returning to it at even faster speeds.
A team led by scientists from the University of Southampton and Imperial College, London, successfully recorded a magnitude 7.1 earthquake on August 29, 2016. The new study is published in the journal Nature Geoscience.
The earthquake ran along the Romanche fracture zone, 560-mile-long fault line under the Atlantic Ocean near the equator, between Brazil and Africa.
Researchers said the quake traveled in one direction between the South American and African tectonic plates, then boomeranged back to the start at ultra-fast speeds — breaking the "seismic sound barrier" — a sonic boom of sorts, as reported by CBS news.
An analysis revealed the quake had two distinct phases. The rupture traveled upward and eastward first, before suddenly reversing and heading back west to the center of the fault at an accelerated speed of 3.7 miles per second.
Only a handful of boomerang earthquakes have ever been recorded — the phenomenon has mostly been theoretical, until now.
According to the scientists, if a similar type of quake occurred on land, it would drastically affect the amount of ground shaking — and possibly widen the affected area. Successfully tracking more boomerang quakes would allow researchers to better predict and assess the hazards from such events, improving impact forecasts.
