By Frederik Tilmann, Bruce M. Howe, and Rhett Butler, via PreventionWeb

Every minute counts in the business of tsunami early warning because tsunami waves often arrive less than 30 minutes after offshore earthquakes. Because most massive subduction zone quakes occur offshore, offshore observations are extremely valuable for quickly detecting and characterizing potential tsunamis. At the same time, unnecessary evacuations are costly and can endanger lives, so false warnings must be minimized.

The current Deep-ocean Assessment and Reporting of Tsunamis (DART) system uses ocean bottom pressure sensors to detect ocean-crossing tsunamis. The DART sensors are too sparse and too distant from shore to provide local warnings, and other real-time solutions like dedicated submarine detection cables come with a hefty price tag. Comprehensive coverage of all endangered subduction zones is out of reach using these systems, particularly in the developing world, but another approach that adds new capabilities to an existing resource could be a significant step in the right direction.

Today, submarine telecommunications cables cross the world’s oceans, and many run through or parallel to margins threatened by subduction zone earthquakes. The cables that currently form this network are not sensing their environment; however, these cables are routinely replaced every 10 to 15 years. Installing suitably modified repeaters along future cables, spaced at nominal 50-kilometer (31-mile) intervals, could provide power and bandwidth for sensors along these cables.

Last November, a group of research scientists, practitioners from earthquake observatories and tsunami warning centers, and engineers gathered for a workshop in Potsdam, Germany, to discuss the viability of a new early warning system that uses enhanced telecommunications cables to create a Science Monitoring and Reliable Telecommunications (SMART) network capable of detecting tsunamis and shaking from great earthquakes. They further discussed how SMART cable sensor arrays would support research into tsunami excitation and propagation, the physics of great earthquakes, and the structure of Earth.