A team from the National Physical Laboratory (NSL) and the Measurement Standards Laboratory of New Zealand (MSL) has successfully detected a multitude of earthquakes in the Pacific Ocean using ultra-stable optical interferometry on undersea cables for the first time.
The team is performing ultra-sensitive optical measurements, converting a branch of the Southern Cross Next seafloor cable, which connects New Zealand to Australia, into an array of sensors for earthquakes and ocean currents. The technique uses the optical fiber inside the cable as the sensing element and gathers environmental data from the seabed, where no other permanent sensors exist.
The Pacific Ocean is a highly seismically active area. Since the measurements began in October 2024, the team has recorded more than 50 earthquakes, with epicenters from tens to hundreds of kilometers from the cable. This high rate of detection will drastically accelerate the research and refinement of the technique, which was previously tested in the less seismically active Atlantic Ocean.
Using NPL’s technique, the team will collect measurements until December 2025. These will be used to develop a worldwide monitoring network of seafloor sensors using the existing subsea infrastructure. According to NPL, this will help fill data gaps and improve understanding in several scientific areas, from seismology to oceanography and climate change.
Giuseppe Marra, principal scientist at NPL, commented, “We are very excited to have started detecting earthquakes and ocean currents in the Tasman Sea. This is the very first test of this technology in the Pacific Ocean; the waters surrounding New Zealand are the perfect laboratory to demonstrate the full potential of these innovative cable-based ocean monitoring techniques for Earth sciences and coastal population protection.
“This very successful UK-NZ project shows how exciting science can bring together countries at the opposite sides of the world. We look forward to more collaborative work with New Zealand.”
Tsunami experts at GNS Science (NZ) will analyze the data to assess its potential for detecting tsunamis and explore how these new technologies can complement more traditional approaches.
Bill Fry, a seismo-tectonophysicist at GNS, explained, “This is an awesome and creative example of leveraging existing data sources and expertise from around the world to increase our eyes and ears in the vast expanse of the Pacific Ocean. We believe that adding this new cabled data will complement other rich data sources and collectively deliver faster and better tsunami warnings that will save lives in New Zealand and across the Pacific.”
The Quantum Seismic Detection Project is enabled by the UK’s International Science Partnership Fund and supported by New Zealand’s Quantum Technologies Aotearoa program.
