Major Forest Fire in Indonesia Disrupts Submarine Cable Operations, RTT Metrics Spike
What Happened
At 22:07 local time on October 8, 2026, a major forest fire was recorded in the Green Forest area of Indonesia. The fire affected a large area and impacted nearby infrastructure. The source of ignition is near key landing points of submarine cables, causing anomalies in the operation of several communication lines.
Cables in Zone
Within a 500 km radius from the fire zone are several submarine cables. Among them are APCN-2 (19,000 km long, commissioned in 2001, operators AT&T and BT), Asia Direct Cable (ADC, 9,988 km, RFS 2024, operators China Telecom and China Unicom), and SEA-H2X (6,000 km, RFS 2026, operators China Mobile and China Unicom). Also in the zone are Asia Submarine-cable Express (ASE, 8,148 km, RFS 2012, operator NTT), Tata TGN-Intra Asia (6,700 km, RFS 2009, operator Tata Communications), and EAC-C2C (36,500 km, RFS 2002, operator Telstra). The cables closest to the fire source are Link 5 Phase-2 (365 km, RFS 2005, operator XLSmart) and Jambi-Batam Cable System (JIBA, 267 km, RFS 2014, operators Indosat Ooredoo and Moratelindo), passing through Kuala Tungkal, Indonesia.
What Our Measurements Show
Network monitoring has revealed significant changes in round-trip time (RTT) metrics on several cables. For example, on APCN-2, the RTT increased from 94.3 ms to 280.3 ms (an increase of 186.0 ms, or 41.8σ from the baseline). On Asia Direct Cable (ADC), RTT rose from 107.6 ms to 212.4 ms (an increase of 104.8 ms, 5.3σ). SEA-H2X showed an increase from 57.0 ms to 178.0 ms (an increase of 121.0 ms, 5.7σ). Similar anomalies were recorded on ASE (+94.0 ms), Tata TGN-IA (+107.1 ms), and EAC-C2C (+137.0 ms). These changes indicate possible impact from the fire on terrestrial segments of infrastructure or associated cooling and power systems.
Context and Risks
Indonesia is a crucial node for submarine cables connecting Asia with other regions. Delays in cable operations could lead to increased response times for users and services, particularly in Southeast Asian countries. Additionally, the proximity of Link 5 Phase-2 and JIBA cables to the fire site raises concerns about their physical integrity. If the fire damages terrestrial stations or cable routes, it may result in more severe consequences for regional and global communications.
Further Monitoring
We will continue to monitor RTT metrics and other parameters of affected cables. Special attention will be given to cables located closest to the fire zone, such as Link 5 Phase-2 and JIBA. We will also monitor recovery efforts in the region and their impact on internet connectivity stability. Updates will be published as new information becomes available.
