Natural disasters such as tsunamis often occur without warning to people living on or close to the coastline.
In such circumstances, personal injury and death may occur. Any early warning of an approaching tsunami is very important. Wave height sensors can be installed on or under buoys to measure wave activity to determine tsunami events.
Often there will be a central authority which maintains a 24/7 tsunami warning centre on an ocean by ocean basis, so staff at that central authority can have knowledge of an approaching tsunami.
Unidata equipment, primarily Neon Remote Loggers, can be set up with cell phone or satellite internet connections to provide monitoring of wave activity and the real time / near real time transmission of that activity to a central tsunami warning centre for example the Pacific Tsunami Warning Centre (PTWC) in Hawaii.
Wave activity is measured at ocean / coastal buoys, with a submersible sensor typically at 2 meters below the surface of the water. An example is a submersible Druck PI sensor / PTX 1560.
The data collection rate is high, typically 10 times per second (10Hz) and a continuous data stream is sent from the measurement station to a central system, which analyses the spectral components of the depth / period of waves similar to the way seismic data is analysed. This data stream is commonly then sent to one of the ocean wide tsunami warning centres.
The measurement of the wave height is relatively straightforward, however it is challenging to collect this sensor data and also transmit the data out at 10Hz on a continual basis. A high capacity / high speed data logger or RTU is needed. A reasonably high bandwidth link, which is an always available channel, is needed. For close to shore buoys, a 3G cell based system could be used. For ocean buoys, an equatorial satellite system is needed.
