Century-Old Technology Inspires Method for Early Warning Tsunami and Earthquake Detection

A million kilometers of fiber optic cable lie on the ocean floor, carrying telecommunication signals across vast stretches of ocean to keep the whole world connected. A new international collaboration, including experts from The University of Texas at Austin, aims to turn them into a global early warning system for tsunamis and earthquakes, as well as a sensor array for monitoring unexplained temperature changes.

Researchers from the Oden Institute for Computational Engineering and Sciences and Institute for Geophysics are part of a team developing Science Monitoring and Reliable Telecommunications (SMART) Cables, which will consist of sensors that “piggyback” on the infrastructure of the existing and expanding undersea telecommunications network. The sensors will allow for low-cost global deep ocean observation to detect temperature, pressure, and seismic acceleration - the rate of change in the Earth’s natural vibrations. Data provided could inform scientists of oncoming underwater earthquakes, volcanic eruptions, and tsunamis, as well as keep track of any long-term changes in the state of the ocean.

The effort will support the UN’s SMART Cables Joint Task Force working to bring the SMART cables concept to fruition by uniting experts from around the world and across disciplines. The task force is chaired by the project’s lead investigator, Bruce Howe of the University of Hawai’i at Mānoa.

The Oden Institute’s role in this project, according to Patrick Heimbach of the Computational Research in Ice and Ocean Systems group (CRIOS), and Professor at UT’s Jackson School of Geosciences, is to test the proposed SMART Cables’ ability to adequately address the questions of oceanographers and geophysicists. Researchers will conduct a series of numerical simulations called Observing System Simulation Experiments which will determine just what quality of data can be taken from the SMART Cables observations and how to optimize it. Initially targeting a region around the island nations of Vanuatu and New Caledonia, a long-term goal is to develop a simulation framework that will support global-scale network design to reveal globally important processes behind ocean change.

“Our focus here is on bottom pressure, temperature, and acoustic data, and their value for ocean climate monitoring,” explained Heimbach, who studies the global circulation of the ocean and its role in climate.

More than 70% of all volcanic eruptions occur beneath the sea, cloaked from scientists’ view by thousands of feet of water. When hot magma comes into direct contact with cold ocean waters, violent blasts, known as “fuel-coolant interaction,” can result in extreme reactions, akin to weapons-grade chemical explosions.  

The international effort could not have been more timely. A month after the project was launched, the Hunga Tonga-Hunga Ha’apai volcano in the Southwest Pacific exploded, causing a sonic boom heard thousands of miles away, thrusting ash 100,000 feet into the sky, rupturing a subsea telecommunications cable, and triggering a tsunami with effects felt as far away as the U.S. West Coast.

“It’s something no one’s ever seen before, so even with additional instrumentation it still would have been very difficult to anticipate what might happen,” said task force member Laura Wallace, a research scientist at the University of Texas Institute for Geophysics and GNS Science in New Zealand who studies the occurrence of earthquakes at undersea subduction zones, which generate the world’s largest earthquakes and tsunami.  

"I think more comprehensive global seabed monitoring, in terms of seafloor pressure and seismology, would have given a lot more understanding of the situation much more quickly than we had in that event."

The initiative, funded by the Moore Foundation, includes experts from University of Hawai’i at Mānoa, Louisiana State University, California Institute of Technology, Subsea Data Systems, Los Alamos National Laboratory, GNS Science, University of Otago (New Zealand), French Institute for Research and Sustainable Development, National University of Vanuatu, Vanuatu Meteorological and Geohazards Department, The Pacific Community (SPC), and the International Tsunami Information Center.