OperationDetectionof tsunamis by DART systemsThedetection of tsunamis is carried out by the Deep-ocean Assessment and Reportingof Tsunami (DART) solution. DART systems consist of an anchored seafloor bottompressure recorder (BPR) and a companion moored surface buoy for real-timecommunications. Sensors that measure the pressure at fixed points on theseafloor in a quiet environment of the deep waters.Whentsunami occurs, the change in pressure is observed on the seafloor and detectedby the sensors.
An acoustic link transmits data from the BPR on the seafloor tothe surface buoy. The BPR collects temperature and pressure at 15-secondintervals. The pressure values are corrected for temperature effects and thepressure is converted to an estimated sea-surface height (height of the oceansurface above the seafloor) by using a constant 670 mm Hg.Thesystem has two data reporting modes, standard and event. The system operatesroutinely in standard mode, in whichfour spot values (of the 15-s data) at 15-minute intervals of the estimated seasurface height are reported at scheduled transmission times the initial fewminutes, followed by 1-minute averages.Event mode messages also containthe time of the initial occurrence of the event. The system returns to standardtransmission after 4 hours of 1-minute real-time transmissions if no furtherevents are detected.
Underwater-to-surface data transmissionThisis realized by using mooring cable. In this system, data from sensor is transmittedto the surface by applying a signal to the internal winding of a cable coupler.This induces a signal in the single-turn secondary winding formed by themooring cable passing through the coupler.
The signal is retrieved at thesurface by a similar configuration. This inductive modem technology provides aconvenient, economical, and reliable solution while still maintainingflexibility. Ground stationsTheTSUSAT system will use two ground stations located in South America, the mainstation will work in Santiago, downloading the data collected by thegeostationary satellite.
An algorithm for detecting variations in measurementsthat could be potentially dangerous might be implemented in near real time inorder to have enough time to alert at the related institutions. A backup groundstation located in Lima can be used in case that the main station has atechnical disruption.Thesubsystems will be redundant being able to use different combinations of them,just in case if one of them stops working due to technical disruptions.
Thisconfigurations will be selected by setting different modes from ground control.