“Listening” to Arctic sea ice: Using fiber optic cables to track when it might break

Junsu Jang – junsu.jang@whoi.edu

Applied Ocean Physics & Engineering, Woods Hole Oceanographic Institute, Woods Hole, MA, 02543, United States

Maddie Smith
Gil Averbuch

Popular version of 1aSP – Sea ice property inversion using distributed acoustic sensing on Arctic landfast ice
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/planner.php?id=ASASPRING2026

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Fig. 1: Schematic of landfast sea ice and the field setup used in this study. Landfast sea ice is attached to the seafloor near the coast, often anchored by grounded ridges (shown here). A fiber optic cable (blue line) is laid along the snow-ice interface and acts as a series of sensors that “listen” to vibrations in the ice. The figure is not to scale. (Figure by Maia LeDoux and the Applied Physics Laboratory Graphics Department; cropped and annotated by the authors to show the fiber optic cable.)

Arctic landfast sea ice is the ice attached to the seafloor near the coast (see Fig. 1). It plays an important role in ocean–atmosphere interactions and supports local communities, wildlife, and coastal stability. As the climate warms, knowing when this ice might crack or break away is increasingly important for both community safety and coastal protection.

Studying landfast ice is difficult. Researchers often have to drill through thick ice or drag along heavy instruments across large areas. Satellites help, but clouds and limited coverage can leave gaps. We need a way to continuously “listen” to the ice over long distances.

Our solution uses a technology called distributed acoustic sensing. It turns a standard fiber optic cable, similar to what brings internet to homes, into hundreds of vibration sensors. Instead of placing many separate instruments, one cable can measure motion along its entire length with high detail.

In 2025, we installed a 2-kilometer-long cable across landfast sea ice in Arctic Alaska (see Fig. 2). A custom sled cut a shallow trench in the snow and ice, laid the cable, and covered it. This setup effectively created about 600 sensors recording vibrations 500 times per second.

Fig. 2: Satellite image of the landfast sea ice showing the 2-kilometer-long fiber optic cable (red line). The cable extends from near the coast out across the ice. Image taken on May 26, 2026. (Image © Planet Labs PBC, CC BY-NC-SA 2.0; labels, cable layout, and axes added by the authors.)

What did we hear? We detected waves traveling through the ice, generated by ocean swells offshore (see Fig. 3). The ice behaves like a thin floating plate sitting on the water, bending as waves pass underneath. By analyzing these motions, we can estimate how stiff or “bendy” the ice is and how much stress it is under from waves and wind.

Fig. 3: Example of measurements from the fiber optic cable. The horizontal axis shows time, and the vertical axis shows distance along the cable (farther from shore upward (see Fig. 2). Red and blue bands indicate the ice stretching and compressing as ocean waves pass underneath, causing the ice to bend. By analyzing these patterns, we can estimate how stiff the ice is and how it responds to waves.

This information will help answer key questions: How thin or weak does the ice need to be before it breaks? What role do waves and wind play? Ultimately, this can improve predictions of “breakout” events, when large pieces of ice detach, and seasonal breakup.

This work is a collaboration with a broader effort, the Arctic PISCES project, to better observe, understand and predict the ocean-ice-atmosphere system in Arctic coastal and inner-shelf regions. With continued monitoring, fiber optic sensing could become a powerful new way to track the stability of Arctic sea ice.