Magnitude 4.6 Earthquake Near Santa Cruz, Philippines Disrupts Submarine Cable Operations

Earthquake in Santa Cruz, Philippines

On October 9, 2026 at 12:17 local time, an earthquake of magnitude 4.6 occurred off the coast of Santa Cruz, Philippines. The epicenter was located approximately 17 km northeast of the city, at a depth of about 10 km. This event caused noticeable changes in the operation of several submarine cables within a radius of 500 km from the epicenter.

Submarine Cables Affected by the Earthquake

The earthquake affected several key submarine cables. Among them:

• APCN-2 (19,000 km, RFS 2001), operator: AT&T, BT, with a node in Batangas, Philippines (68.1 km from the epicenter).
• Asia Direct Cable (ADC) (9,988 km, RFS 2024), operator: China Telecom, China Unicom, also through Batangas (68.1 km).
• EAC-C2C (36,500 km, RFS 2002), operator: Telstra, with a node in Batangas (68.1 km).
• Asia Submarine-cable Express (ASE) (8,148 km, RFS 2012), operator: NTT, PLDT, through Daet, Philippines (255.1 km).
• SEA-H2X (6,000 km, RFS 2026), operator: China Mobile, China Unicom, through La Union, Philippines (376.1 km).

Also in the zone are the cables SJC, BPSCS, and JUPITER, but no significant changes in their operation have been recorded.

Metered Anomalies on Cables

Our monitoring systems have detected significant changes in round-trip time (RTT) on several cables:

• APCN-2: RTT increased from 94.3 ms to 300.3 ms (delta +206.0 ms, 46.3σ).
• ADC: RTT increased from 107.6 ms to 197.8 ms (delta +90.2 ms, 4.5σ).
• EAC-C2C: RTT increased from 84.7 ms to 227.6 ms (delta +142.8 ms, 12.2σ).
• ASE: RTT increased from 89.3 ms to 191.8 ms (delta +102.5 ms, 2.8σ).
• SEA-H2X: RTT increased from 59.4 ms to 210.2 ms (delta +150.8 ms, 6.7σ).

These changes indicate possible damage or temporary failures in the cables, especially those closest to the epicenter.

Impact on Internet Traffic

Anomalies in the operation of cables may affect internet traffic routing in the Southeast Asia region. Cables such as APCN-2 and ADC play a crucial role in connecting the Philippines with other countries in the region, including China, Japan, and Singapore. Increased delays can lead to a decrease in service quality, especially for applications requiring low latency, such as video conferencing and online games.

However, due to the availability of alternative routes such as SJC and JUPITER, global operators can redirect some traffic, minimizing the impact on users.

Plans for Further Monitoring

We will continue to monitor the condition of cables in the region, especially those where anomalies have already been detected. Special attention will be paid to APCN-2, ADC, and EAC-C2C, as they showed the largest deviations in delay. We will also keep an eye on any changes in the operation of SJC and JUPITER to promptly identify any new issues.

Information about cable conditions will be updated in real-time on our platform to ensure timely notification for operators and users.