DART Tracking Tsunamis Deep-ocean tsunami detection buoys readiness and networking for saving lives скачать в хорошем качестве

DART Tracking Tsunamis Deep-ocean tsunami detection buoys readiness and networking for saving lives

Deep-ocean tsunami detection buoys are one of two types of instrument used by the Bureau of Meteorology (Bureau) to confirm the existence of tsunami waves generated by undersea earthquakes. These buoys observe and record changes in sea level out in the deep ocean. This enhances the capability for early detection and real-time reporting of tsunamis before they reach land. Earthquakes, the usual cause of tsunamis, cannot be predicted in time, ... Neither historical records nor current scientific theory can accurately tell us when earthquakes will occur. Therefore, tsunami prediction can only be done after an earthquake has occurred. How does a deep-ocean tsunami detection buoy work? A typical tsunami buoy system comprises two components; the pressure sensor anchored to the sea floor and the surface buoy. The sensor on the sea floor measures the change in height of the water column above by measuring associated changes in the water pressure. This water column height is communicated to the surface buoy by acoustic telemetry and then relayed via satellite to the tsunami warning centre. The system has two modes - 'standard' and 'event'. The system generally operates in 'standard' mode, where it routinely collects sea level information and reports via satellite at relatively low frequency transmission intervals (i.e. every 15 minutes). This helps to conserve battery life and hence extend the deployment life. The tsunami buoy is triggered into 'event' mode when the pressure sensor first detects the faster moving seismic wave moving through the sea floor. It then commences reporting sea level information at one minute intervals to enable rapid verification of the possible existence of a tsunami. The system returns to standard mode after 4 hours if no further seismic events are detected. Data from tsunami detection buoys are made freely available to the international community and the tsunami warning centers of other countries in real-time using the World Meteorological Organization's dedicated Global Telecommunication System (WMO GTS).