5.1 Earthquake South of Pagar Alam, Indonesia; B2JS Cable Shows Operational Anomalies
What Happened
On August 10, 2026, at 20:08 local time, an earthquake with a magnitude of 5.1 struck 232 km south-southwest of Pagar Alam city, Indonesia. The epicenter was located in the Indian Ocean, a region that hosts critical submarine cable routes connecting Indonesia to other Southeast Asian countries and Australia. These cables are vital for international internet connectivity and data transmission, making the region strategically significant for global communication infrastructure. The earthquake led to anomalies in the operation of one of the cables in the area, highlighting the potential vulnerability of submarine networks to seismic activity.
Cables in Zone
Within a 500 km radius of the earthquake's epicenter, several submarine cables are positioned. These cables form a dense network that supports high-speed data exchange across the region. The closest cable to the epicenter is the JaSuKa cable, owned by Telkom Indonesia, with an exit point in Bandar Lampung located 325.4 km away. The JaSuKa cable is a key domestic network connecting Java, Sumatra, and Kalimantan, ensuring robust communication within Indonesia. Other significant cables in the area include the Jakarta-Bangka-Batam-Singapore (B2JS) cable operated by Triasmitra, the Australia-Singapore Cable (ASC) managed by Vocus Communications, and the Sumatera Bangka Cable System (SBCS) owned by Telkom Indonesia. Among these, the B2JS cable, which spans 759 km and was commissioned in 2013, experienced the most pronounced anomalies following the seismic event.
What Our Measurements Show
GeoCables' advanced monitoring systems detected a significant increase in round-trip time (RTT) on the B2JS cable. Prior to the earthquake, the average RTT for this cable was 25.3 milliseconds. Following the seismic activity, the RTT surged to 165.0 milliseconds, marking an increase of 139.7 milliseconds, equivalent to 7.1 standard deviations above the baseline level. This sharp deviation strongly suggests potential physical impact on the cable or its associated equipment. Despite the anomalies observed on the B2JS cable, other cables in the region, including JaSuKa, ASC, and SBCS, maintained stable operational parameters throughout the event. This stability underscores the resilience of the broader network and its ability to mitigate localized disruptions.
Context and Risks
Submarine cables in the Indian Ocean region are indispensable for maintaining seamless internet connectivity between Indonesia, Singapore, and Australia. These cables handle a significant portion of international data traffic, supporting economic activities, communication, and digital services. The anomaly detected on the B2JS cable could lead to temporary disruptions in traffic routing, resulting in increased latency and reduced bandwidth capacity for affected users. However, the operational stability of other nearby cables, such as JaSuKa and ASC, plays a crucial role in minimizing the overall impact on connectivity. This event underscores the importance of continuous monitoring and rapid response to ensure the reliability of these critical infrastructures.
Further Monitoring
GeoCables will maintain vigilant monitoring of the B2JS cable to assess whether the anomalies persist or resolve over time. Our systems will track changes in RTT and other key performance indicators to identify any potential infrastructure damage or degradation. Concurrently, we will continue to monitor the operational status of other cables in the region, including JaSuKa, ASC, and SBCS, to ensure their continued stability and performance. Updates and findings from our monitoring efforts will be promptly published on our portal, ensuring transparency and timely information for stakeholders and the broader community.
