Researchers at the Australian National University (ANU) have made a breakthrough in understanding one of the earth’s biggest faults. For the first time in history, a team of scientists shed some light on how a 7.2 km-deep abyss formed in the Pacific Ocean.
The Banda Detachment fault is located in eastern Indonesia and thanks to the finding, researchers will be able to have a better understanding of the dangers of future tsunamis and earthquakes that take place in the area. The fault affects the Ring of Fire, which is located in the Pacific Ocean, where 90% of the world’s earthquakes and 75% of all active volcanoes occur.
In order to investigate the massive chasm, geologists at ANU analyzed maps of the Banda Sea region thanks to new technology that allows a better mapping of the deep ocean. They discovered that rocks sitting at the bottom of the deep sea looked like they are covered in massive parallel scars. This suggests that a massive piece of crust bigger than Belgium was ripped apart by a movement in the oceanic plates, which formed the deep depression in the ocean floor known as the deep sea.
This activity also left behind the biggest exposed fault plane ever detected on earth, which scientists labelled the Banda Detachment over 90 years ago. In an interview with ANU, Dr. Jonathan Pownall said that the discovery will help explain how one of the Earth’s deepest seas became so deep, and that this knowledge could help improve our understanding of the tsunami risk in the area.
Professor Gordon Lister said that this was the first time that fault has been seen and actually documented by scientists using image capture technology. He said their knowledge of the fault was based on previous superficial data and their understanding of the region’s geology.
“I was stunned to see the hypothesized fault plane, this time not on a computer screen, but poking above the waves,” Dr. Pownall said. “This demonstrates the extreme amount of extension that must have taken place as the oceanic crust was thinned, in some places to zero.”
The Ring of Fire is where all of history’s most disastrous earthquakes, tsunamis and volcanoes have taken place, so an understanding of the Banda Detachment could help save millions of lives. In Chile alone, the largest earthquake recorded was of a 9.2 magnitude and it took place in May 22, 1960. The resulting tsunami, a 25 meter (75 feet) high surge, killed over 1,500 people. More recently, in 2004, a 9.2 magnitude earthquake in Indonesia killed 230,000 people, mostly due to the tsunami that took place after. In Japan, another nation deeply affected by the Ring of Fire, a 2011 earthquake and the resulting tsunami killed over 15,000 people. The tsunami also triggered a nuclear meltdown that forced the Japanese government to evacuate hundreds of thousands of people residing in the areas adjacent to the nuclear reactors.