India’s tsunami early warning system combines seismic monitoring, ocean sensors and rapid modelling to detect threats within minutes
Operated by INCOIS in Hyderabad, the system verifies earthquakes using real-time ocean data before issuing public alerts
Designed after the 2004 Indian Ocean tsunami, the network now serves India’s coastline and the wider Indian Ocean region
When the 2004 Indian Ocean tsunami devastated coastlines across Asia, it forced a complete rethinking of how nations detect and warn against fast-moving ocean threats. India’s response is centred in Hyderabad, where the Indian National Centre for Ocean Information Services, also known as INCOIS, runs the Indian Tsunami Early Warning Centre. Today, the system combines seismic monitoring, ocean sensors, mathematical modelling and rapid communication networks to turn raw scientific data into life-saving warnings, often within minutes.
The warning chain begins with the detection of earthquakes. A nationwide network of seismic stations continuously monitors tremors and immediately sends preliminary information, such as the location, depth and magnitude, to INCOIS and the National Centre for Seismology. These land-based measurements are the fastest means of identifying earthquakes that may generate tsunamis.
However, not every undersea earthquake produces a tsunami. Therefore, to confirm whether the sea has actually been disturbed, INCOIS relies on a real-time ocean observation network. This network includes bottom pressure recorders placed on the seafloor, deep-ocean tsunami buoys and coastal tide gauges. These instruments detect sudden changes in sea level, which are clear signatures of a tsunami wave passing through the ocean.
Once detection data arrives, INCOIS uses powerful computers to simulate the possible behaviour of the tsunami. The centre maintains a large database of pre-calculated scenarios (outputs from numerical modelling) that represent different earthquake situations. By matching the real event to the closest scenario, the system quickly generates forecasts of expected wave heights and arrival times along various coastal regions. These models are essential for preparing coastal impact maps and for helping disaster management authorities decide whether evacuation is necessary.
Because false alarms can cause confusion and economic loss, INCOIS follows a careful verification process. Initial earthquake information triggers watch messages, but definitive public warnings are issued only after confirmation from ocean sensors such as pressure recorders, buoys and tide gauges. This step-by-step procedure is designed to maintain accuracy without losing crucial time.
Once the system confirms a threat, warnings must reach people quickly. INCOIS operates day and night and issues official bulletins through secure communication channels to government agencies, disaster management authorities, the Coast Guard and other stakeholders. Simplified public advisories are released through INCOIS portals, national communication systems and the media. Newer systems also include mobile-based alerts and applications to reach coastal communities directly.
INCOIS has continued to improve its capabilities. It is recognised as a regional tsunami service provider by UNESCO’s Intergovernmental Oceanographic Commission, reflecting its importance in the Indian Ocean region. Recent initiatives include the development of an advanced underwater smart cable equipped with seafloor sensors to collect real-time data from seismically active zones. This system aims to overcome the limitations of surface buoys and will help detect tsunamis generated by undersea landslides or other non-seismic sources. INCOIS is also mapping underwater landslide zones to better understand hidden triggers that could generate sudden tsunamis.
India’s tsunami early warning system is therefore a comprehensive operational network consisting of ground-based sensors, ocean-based instruments, high-speed modelling tools, reliable verification methods and robust dissemination pathways. It is a blend of science, technology and coordination. While this system significantly improves safety along India’s long coastline, community awareness and rapid response remain equally important. Technology can warn, but people must act swiftly to stay safe.
Praveen Sakalya is researcher on Tsunami-Floods and Coastal Processes-Assistant Professor in Physics, St Thomas College, Kozhencherry, Pathanamthitta, Kerala. Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth