Major Forest Fire in Indonesia Causes Anomalies in INDIGO-West Submarine Cable
What Happened
On September 5, 2026, at 22:13 local time, a major forest fire was reported in Indonesia. The ignition point is located in a densely forested area, which has contributed to the rapid spread of the fire. This region is not only ecologically significant but also strategically important due to its proximity to several key submarine cables that provide critical internet connectivity to Indonesia and neighboring countries. These cables play a vital role in facilitating communication, commerce, and data exchange across Southeast Asia and beyond.
Cables in Zone
Within a 500 km radius of the fire zone, GeoCables has identified several submarine cables that are integral to the region's connectivity. These include:
- INDIGO-West: Stretching 4600 km and operational since 2019, this cable is co-owned by AARNET and Google. It connects Singapore to Perth, Australia, and serves as a critical link for research institutions and businesses. It is located 399.1 km from the fire zone.
- PASULI: A shorter cable at 40 km in length, operational since 2019, and the closest to the fire zone at a distance of 97.4 km.
- Sumatera Bangka Cable System (SBCS): Spanning 57 km and operational since 2014, this cable connects Sumatra and Bangka Island.
- Tanjung Pandan-Sungai Kakap: A 348 km cable operational since 2019, linking Tanjung Pandan and Sungai Kakap.
While PASULI is geographically closest to the fire, INDIGO-West has already shown operational anomalies, highlighting the interconnected nature of submarine cables and terrestrial infrastructure in the region.
What Our Measurements Show
GeoCables' monitoring systems detected significant anomalies in the operation of the INDIGO-West cable. Specifically, the round-trip time (RTT) experienced a marked increase. The average RTT for INDIGO-West is typically 59.1 milliseconds (ms). However, following the onset of the fire, RTT surged to 232.1 ms - a jump of 173.0 ms, which is 9.3 standard deviations above baseline levels. This substantial increase suggests potential disruptions in terrestrial infrastructure nodes that support the cable's operation.
Other cables in the vicinity, including PASULI, SBCS, and Tanjung Pandan-Sungai Kakap, remain fully operational with no detected anomalies. Their stability could be attributed to their geographical positioning and the robustness of their infrastructure, which appears to be unaffected by the fire's immediate impact.
Context and Risks
Indonesia serves as a critical hub for submarine cables that connect Southeast Asia to Australia and other global regions. The INDIGO-West cable, in particular, is a cornerstone for international data traffic, supporting a range of applications from academic research to commercial operations. An increase in RTT can significantly impact the performance of latency-sensitive applications such as video conferencing, online gaming, and financial transactions. While the fire's direct impact on submarine cables is currently limited, the potential for damage to terrestrial stations and supporting infrastructure poses a significant risk. If the fire spreads further, it could lead to broader disruptions in connectivity and data flow.
Further Monitoring
GeoCables is actively monitoring the situation and will continue to track the performance of all submarine cables within the fire zone. Special attention is being given to INDIGO-West and PASULI due to their proximity and operational significance. Key metrics such as RTT and other performance indicators are under constant observation to detect any signs of further degradation. Additionally, GeoCables is analyzing data related to terrestrial infrastructure in the region to assess potential impacts on cable operations. Updates on the situation will be provided as new findings emerge, ensuring stakeholders are informed of any developments.
