Magnitude 6.5 earthquake west of Nikolski, Alaska; AU-Aleutian cable fully operational

What Happened

On September 17, 2026, at 17:19:53 UTC, an earthquake of magnitude 6.5 occurred 165 km west of Nikolski, Alaska. The epicenter was located in the Aleutian Islands, a region renowned for its seismic activity due to its position along the Pacific Ring of Fire. The earthquake was registered at a depth of approximately 10 km, classifying it as a shallow event. Shallow earthquakes are often more likely to cause surface-level disruptions and pose potential risks to infrastructure, including submarine cables, due to the proximity of the seismic energy to the Earth's surface.

Cables in Zone

Within a radius of 500 km from the earthquake's epicenter lies the submarine cable AU-Aleutian, a critical communication link brought into operation in 2022. This cable spans a total length of 1491 km and plays a vital role in connecting remote areas of the Aleutian Islands with mainland Alaska. The nearest segment of the cable to the epicenter passes through an access point in Akutan, Alaska, situated approximately 396 km away. Owned and operated by GCI Communication Corp, the AU-Aleutian cable is a lifeline for communities in this isolated region, providing essential connectivity for internet, phone, and data services.

What Our Measurements Show

GeoCables' monitoring systems confirmed that the AU-Aleutian cable remained fully operational following the earthquake. The round-trip time (RTT) for the cable was measured at a consistent 35-40 ms, which aligns with normal performance levels for this route. No deviations in delay, bandwidth, or other operational parameters were detected, indicating that the cable's infrastructure demonstrated remarkable resilience to the seismic event. This stability highlights the robust engineering and design of the AU-Aleutian cable, which is built to withstand the challenging conditions of the Aleutian Islands.

Context and Risks

The Aleutian Islands are situated within one of the most geologically active regions on Earth, the Pacific Ring of Fire. This area is characterized by frequent earthquakes and volcanic activity, which pose risks to submarine cables due to potential underwater landslides and shifting tectonic plates. Despite these challenges, the AU-Aleutian cable has proven its reliability by maintaining uninterrupted service during a magnitude 6.5 earthquake. The cable's resilience underscores the importance of advanced engineering techniques and proactive risk mitigation strategies in ensuring the stability of critical communication infrastructure in seismically active zones.

Further Monitoring

GeoCables will continue its comprehensive monitoring of the AU-Aleutian cable's performance, focusing on RTT, throughput, and physical integrity. While no immediate disruptions have been observed, ongoing assessments will ensure that any latent issues, such as micro-damages or delayed impacts, are promptly identified and addressed. Additionally, GeoCables will maintain vigilant observation of seismic activity in the region to evaluate potential risks to submarine infrastructure. The proactive approach to monitoring ensures the continued reliability of communication services for the communities relying on the AU-Aleutian cable.