For the last 90 years, the so-called Banda Detachment fault has remained an unsolved mystery to geologists.
Nobody has been able to explain, how a 7.2km (4.4 mile) deep abyss beneath the Banda Sea located in eastern Indonesia, became so deep.
Now, for the first time, researchers have seen, documented and worked out how this mysterious and dangerous abyss formed.
It is important to add that their findings are extremely important because they will help researchers predict future tsunamis and earthquakes in the area, which is part of the Ring of Fire, a very dangerous zone around the Pacific Ocean basin.
The team found the rocks flooring the seas are cut by hundreds of straight parallel scars; these scars show that a piece of crust bigger than Belgium or Tasmania must have been ripped apart by 120 km of extension along a low-angle crack, or detachment fault, to form the present-day ocean-floor depression.
The Banda Detachment represents a rip in the ocean floor exposed over 60,000 square kilometers.
Dr Pownall said he was on a boat journey in eastern Indonesia in July when he noticed the prominent landforms consistent with surface extensions of the fault line.
The research has been published in GeoScience World.