Incident report · 2026092602
Hokkaido-Sakhalin Cable System (HSCS): latency up to 2.1× normal, 26 Sep 2026
Resolved · 5h 32m
What we measured
| Cable | Hokkaido-Sakhalin Cable System (HSCS) |
| Segment | Ishikari, JP → Nevelsk, RU |
| Detected | 2026-09-26 21:02 UTC |
| Resolved | 2026-09-27 02:34 UTC |
| Duration | 5h 32m |
| Observed latency | 215.9 ms |
| Baseline | 108.4 ms · 2.06× |
| Increase | +106% |
| Severity | warning |
Who is affected
Countries where Hokkaido-Sakhalin Cable System (HSCS) comes ashore, how much of their submarine diversity this cable represents, and what our measurements into them show.
| Country | Dependence on this cable | Other submarine cables | What the measurements show |
|---|---|---|---|
| Japan resilience index: 100 · resilient |
1 of 52 cables (2% of submarine diversity) | 5 Villages 6 Islands, APCN-2, Apricot +48 more | median 167 ms today vs 210 ms over 30 days (280 routes) - faster |
| Russia resilience index: 100 · resilient |
1 of 13 cables (8% of submarine diversity) | BCS North - Phase 2, Energy Bridge Cable, Far East Submarine Cable System +9 more | median 56 ms today vs 61 ms over 30 days (1276 routes) - unchanged |
Dependence is structural (share of the country's submarine cables), not a traffic share: real traffic distribution across cables is not public.
Timeline
- Alert 2026092602: warning - ratio 2.06x
- Alert #208 improving: 1/3 consecutive OK
- Alert #208 resolved: RTT 215.85ms (baseline 108.43ms), 3 consecutive OK
Detection method
Latency is sampled continuously from our probe network. An alert opens when round-trip time to a monitored endpoint holds above its rolling baseline, and closes automatically once it returns. Full method is described on the methodology page.
How to cite
GeoCables (2026). Incident 2026092602: Hokkaido-Sakhalin Cable System (HSCS). https://geocables.com/incident/2026092602
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