Earthquake Near Japan: Impact on Submarine Cables and Global Connectivity

What Happened

On June 26, 2026, at 16:29 Coordinated Universal Time (UTC), an earthquake with a magnitude of 5.7 occurred near Osino, Japan. This seismic event took place in a region known for its tectonic activity, as Japan is located on the Pacific Ring of Fire, a zone characterized by frequent earthquakes and volcanic activity. The proximity of the epicenter to key submarine cable landing points raised immediate concerns about potential impacts on global communication infrastructure.

Cables in the Area

Within a 500 km radius of the earthquake's epicenter, several critically important submarine cables are located. These cables form the backbone of international internet and telecommunications networks, connecting Japan with other parts of Asia, Europe, Australia, and the world. The cables in this area include:

• FLAG Europe-Asia (FEA): Spanning 28,000 km and operational since 1997, this cable connects Europe and Asia, with a landing point in Miura, Japan, just 81.1 km from the epicenter. Its proximity to the earthquake highlights its strategic importance in maintaining intercontinental connectivity.
• Unity/EAC-Pacific: This 9,620 km cable, operational since 2010, is a joint project by Bharti Airtel, Google, and others. It connects Japan with the United States and other Pacific countries, with a landing point in Chikura, Japan, 116.7 km from the epicenter.
• Candle: A new 8,000 km cable, operational since 2028, owned by IPS, Inc. It connects Japan with other parts of Asia, with a landing point in Maruyama, Japan, 116.7 km from the epicenter.
• Australia-Japan Cable (AJC): This 12,700 km cable, operational since 2001, is owned by AT&T and NTT. It connects Japan with Australia and other Pacific regions, with a landing point in Maruyama, Japan, 116.7 km from the epicenter.
• Asia Submarine-cable Express (ASE)/Cahaya Malaysia: Spanning 8,148 km and operational since 2012, this cable is owned by NTT and PLDT. It connects Japan with Southeast Asia, with a landing point in Maruyama, Japan, 116.7 km from the epicenter.
• Asia Pacific Gateway (APG): This 10,400 km cable, operational since 2016, is owned by China Mobile, China Telecom, and others. It connects Japan with various parts of Asia, with a landing point in Maruyama, Japan, 116.7 km from the epicenter.
• Asia Direct Cable (ADC): Operational since 2024, this 9,988 km cable is owned by China Telecom and China Unicom. It connects Japan with other Asian countries, with a landing point in Maruyama, Japan, 116.7 km from the epicenter.
• E2A: A 12,500 km cable, operational since 2029, owned by Chunghwa Telecom and SK Broadband. It connects Japan with East Asia, with a landing point in Maruyama, Japan, 116.7 km from the epicenter.

What Our Measurements Show

GeoCables' monitoring systems have confirmed the stability of all submarine cables in the affected region. No anomalies or increases in baseline round-trip time (RTT) were detected, indicating the operational integrity of the cables remains intact. This resilience underscores the reliability of the engineering and construction of these critical infrastructures, which are designed to withstand seismic activity in tectonically active regions like Japan.

Context and Risks

Submarine cables are vital arteries of global internet and telecommunications networks, carrying over 95% of international data traffic. In seismically active regions, earthquakes pose a significant risk to these infrastructures, potentially causing physical damage to cables or disruptions in data transmission. However, the cables in this area have demonstrated their ability to withstand seismic shocks without any interruptions. This resilience is a testament to the rigorous standards and advanced technologies applied in their construction and maintenance.

Ongoing Monitoring

GeoCables will continue to closely monitor the situation, utilizing real-time data and advanced analytics to track any changes in cable conditions or transmission parameters. This proactive approach ensures timely detection and resolution of any potential issues, maintaining the reliability and stability of global communication networks.