An “innovative” journey to unravel the inner secrets of the Earth
A major mission to recover 27 seismometers from the rugged ocean floor near Macquarie Island in the Southern Ocean will reveal the secrets of the Earth’s inner layers and what triggers earthquakes and sub-tsunamis. sailors.
The three-week return trip lasted more than 12 months, following the deployment of the seismometers in October 2020.
The instruments at the bottom of the ocean form a giant telescope pointing towards the center of the Earth and have collected data that will provide vital information on some of the most violent underwater earthquakes on Earth.
They could also help scientists understand future earthquakes and tsunamis that could affect coastal populations in Australia and New Zealand.
The ‘revolutionary’ journey also traverses some of the world’s rugged mountain ranges to ocean depths of over 5.5 kilometers in an isolated region known as Macquarie Ridge, midway between New Brunswick. Zealand and Antarctica. The steepness of the slopes of the Macquarie Ridge exceeds those of the Himalayas, the Alps or the Alaska Range.
The New Zealand research vessel RV Tangaroa was engaged by the CSIRO Marine National Facility for the 24-day trip to the Southern Ocean and departed Wellington on November 10.
Chief Scientist Professor Hrvoje TkalÄiÄ and Chief Researcher Dr Caroline Eakin from the School of Earth Sciences Research at Australian National University (ANU) and Professor Mike Coffin from the ‘University of Tasmania lead the research team.
“These devices record the movement of the ground continuously, from distant earthquakes, storms, whales and other phenomena due to the ocean-atmosphere-solid earth system interaction, to earthquakes in the region itself. “said Professor TkalÄiÄ.
“It’s in an area where the Australian Plate meets the Pacific Plate, but it’s not known as an active subduction zone, so these earthquakes remain a mystery to us.”
The mission to map the seabed was a difficult expedition. The rough seas caused the crew of last year’s initial voyage to be thrown from their bunks despite the anti-roll ballast capability of the research vessel RV Investigator.
“The instruments surrounded Macquarie Island, a region in the furious 1950s latitudes of the Southern Ocean known for its seas and extreme weather conditions,” said Professor TkalÄiÄ.
âThe weather was often unforgiving during our instrument deployments. We had to deal with high winds and waves that forced us to âwantâ or shelter downwind of Macquarie Island for approximately 40% of our time in the study area. “
The next step will be to analyze the data from the seismometers which will hopefully reveal the secrets of the Earth’s plate collision.
âScientifically, the most exciting payoff from this project might be that it could help us add missing pieces to one of the biggest puzzles in plate tectonics – how subduction begins,â Prof TkalÄiÄ said.
“Researchers have pondered this question for decades, probing active and extinct subduction zones around the world for clues, although the picture remains murky.”
The research is an international collaboration led by ANU and supported by the Australian Research Council, a sea time grant from the CSIRO Marine National Facility, AuScope / Australian National Seismic Imaging Resource, the UK’s Natural Environment Research Council, Australian Antarctic Division, Tasmania Parks and Wildlife Service, Geoscience Australia with in-kind support from ANU, University of Tasmania, University of Cambridge and California Institute of Technology.