Scientists use the Southern Cross NEXT submarine cable for earthquake detection

A collaboration between the Measurement Standards Laboratory of New Zealand (MSL) and the UK’s National Physical Laboratory (NPL) will create an undersea earthquake detection system using the Southern Cross NEXT fiber optic cable.

Using a technique developed by NPL in 2021 and derived from techniques used in quantum sciences, the scientists behind the project will test the method on a section of the NEXT cable, which spans 3,876 kilometers between New- Zeeland and Australia in a seismically active area.

The scientists will convert the section of cable on the seabed into a series of sensors that can collect environmental data over existing fiber optic infrastructure, without the need to install new hardware.

Data collected from the cable sensor array on the seabed can be used to detect earthquakes and act as an early tsunami warning, the NPL said.

“It’s another great example of improving measurements that give us access to in-depth information that in turn pushes the boundaries of our metrology. Not only that, but we also see that precision measurements support our ambitions for a sustainable future.

“Our earliest timekeeping devices – calendars – allowed us to live according to the rhythms of our natural world. And now the next generation of clocks is unlocking a new wealth of insight into our planet,” said Annette Koo, director and chief metrologist at MSL.

Giuseppe Mara, chief scientist at NPL, explained that the joint UK-NZ project will test the UK laboratory’s pioneering seabed cable-based environmental sensing in one of the most seismically active regions in the world.

“This will significantly advance research into these innovative environmental sensing techniques, impacting a number of scientific areas, from seismology to oceanography, as well as future societal applications, such as in early tsunami warning systems,” Mara said.

“This project is a testament to how science is able to bring together minds from the world’s antipodeans to advance our knowledge of how our planet works and have a positive impact on society,” he added.

NPL has already demonstrated the technology in the Atlantic Ocean, on a 5,860 kilometer fiber optic cable between Great Britain and Canada.

Currently, there are only a handful of permanent ocean floor sensors in place around the world because installing and maintaining them is challenging and prohibitively expensive, NPL said.

The NPL-MSL project is part of a new partnership agreement with New Zealand, announced by UK Minister for Science, Research and Innovation Andrew Griffith, at the Organization for Economic Co-operation and Development (OECD) Science and Innovation Ministerial event Technological Policy in Paris.

The use of fiber optic cables for sensing purposes is already taking place in New Zealand.

Scientists from Victoria University and the Australian National University have installed sensors on the Chorus fiber optic cable that crosses the Alpine Fault at Haast, for seismological research.

The scientists use Distributed Acoustic Sensing (DAS) technology to detect ground movements at the fault, which has a 75% chance of erupting in the next 50 years, potentially causing an earthquake of magnitude greater than 8 on the scale van Richter will cause.

By emitting pulses of light, some of which is scattered as it moves along the fiber optic cable, scientists can detect vibrations caused by passing seismic waves. The system generates large amounts of data, approximately 1 terabyte per day, providing highly detailed information and insights about the Alpine Fault.