As part of the Indian Tsunami Early Warning System, a real-time network of Tsunami Buoys (consisting of Bottom Pressure Recording -BPR and Surface buoy) has been established by INCOIS and the National Institute of Ocean Technology (NIOT). The network is designed to detect, measure and monitor tsunamis. The network comprises 7 Tsunami Buoys (4 Indigenous Tsunami Buoys by NIOT and 3 SAIC Tsunami buoys by INCOIS) transmitting real-time data through satellite communication to INCOIS at Hyderabad and NIOT at Chennai simultaneously for processing and interpretation.

Each BPR is strategically placed in the open ocean near the tsunamigenic source zones in the Andaman & Nicobar Islands and the Makran subduction zone. At the same time, they are far enough from the earthquake zone so that the tsunami wave signal can be clearly distinguished from the seismic Rayleigh wave.

The Tsunami buoy system consists of two parts: a Bottom Pressure Recorder (BPR) placed on the seafloor to measure the water level height and a Surface Buoy placed on the sea surface to communicate between the BPR & satellite. The BPR collects (records) temperature and pressure values at 15-second intervals, the pressure values are corrected for temperature effects and are converted to an estimated sea-surface height by using a constant 670 mm/psia. An acoustic link transmits data from the BPR to the surface buoy.

The system has two data reporting modes: normal and event mode. The system operates routinely in normal mode, where four values are recorded at 15-minute intervals. When the internal detection software detects any changes in the water level from the expected value, the system automatically switches into event/Tsunami response mode transmission, where 15-second values are transmitted during the initial few minutes, followed by updates every 1 minute. The buoys remain in the tsunami response mode for 3 hours and automatically return to normal mode. The tsunami buoys are capable of detecting minor water-level changes of even 1 cm at water depths up to 6 km (Meinig et al).

The BPR uses a piezoelectric pressure transducer to make 15 seconds-averaged measurements of the pressure exerted on it by the overlying water column. The tsunami detection algorithm predicts the next value of each 15-second measurement by a Newton cubic extrapolation of previous observations. It is triggered when measured and predicted values differ by more than the 30 mm threshold. The tsunami buoy system has a two-way communication link and is thus able to send and receive data from the Tsunami Warning Centre. The INCOIS and NIOT were equipped with computing hardware for data reception, communication hubs, data processing, visualization and dissemination.