In light of the
events of the 2004
tsunami in South Asia, there has been an increasing concern about
future tsunami threats, and with it, growing interest in tsunami
detection and prevention systems. Part of our group’s task was to
research existing tsunami detection systems, consider their
effectiveness and feasibility and also to theorize new systems and
ways of improving existing ones.
determined that the system that seems the most effective and the most
feasible is a bottom pressure recorder(BPR)-buoy system. This system
is the one currently being used in the coasts of Japan and the
Pacific coast of the United States (the DART system), with slight
variations. We have chosen to model our system after the DART system,
of proven effectiveness and hardiness1. Considering the
specifications of the system and what we need the system to detect,
it was concluded that this was a fitting choice for modeling our
sensor system for Micronesia and Peru.
The BPR uses a quartz crystal resonator to measure ambient pressure and temperature(the temperature data is important, as it affects the pressure measurement. The resonator uses a thin quartz crystal beam, electrically induced to vibrate at its lowest resonant mode. It communicates these measurements to the surface buoy through an acoustic modem. The tsunameter can be deployed down to a depth of 6000 meters. The tsunameter's battery packs allow it a projected work life of four years on the ocean bottom.
If the tsunameter takes a measurement within the tsunami threshold, it will change to “Event Mode” and send data more frequently, as to trace the movement of the wave. It will continue sending data until the detection threshold is no longer exceeded.
The surface buoy relays information and commands between the tsunameter and the satellite network the system links up to. The buoy's transducers are protected by a baffle of steel, lead and foam, and are cushioned by rubber pads. It has two identical systems as a fail-safe for the relaying of the data. Generally, only one system will be transmitting data at a time, but once the “Event Mode” is triggered, both systems will transmit the data simultaneously. The surface buoy is moored to the ocean bottom, to maintain it within the transmission cone of the tsunameter's modem. Its batteries allow it a projected work life of two years2.
As the name states, this system would use satellites to detect tsunamis. Though the movement of the December 2004 tsunami in South Asia was recorded by satellites, and the aircraft could determine the speed of the waves, it was sheer luck that the satellites observed the phenomenon, and it took 5 hours to process the images and information, which is quite obviously much longer than would be a feasible amount of time for warning about a tsunami. An initial component for a satellite system could be the Jason 2 satellite, to be launched in 2008, by the NOAA and Eurnetsat3.
When speaking of a satellite detection system, it would be imperative to mention the current initiative to set up this satellite network, the Global Earth Observation System of Systems (GEOSS). Though not much has been completely established, the GEOSS will be a system of systems to collect data on meteorological and climate change and allow nations quick and easy access to this information. This system, once properly researched and set up, would include a tsunami detection system4.
However, there is much research that still needs to be done when it comes to the use of satellites in tsunami detection. Also, the initial cost of setting up a satellite network is high. However, once the research is done, it would be an effective backup and would provide information to complement that of a BPR-buoy system. It is highly unlikely that satellites will absolutely replace the buoy systems, but it is not out of the question to do this once the technology and the knowledge are advanced enough.
1 Bernard, E.N. (2005, May). The U.S. National Tsunami Hazard Mitigation Program: A Successful State–Federal Partnership. Natural Hazards, 35(1), 5 – 24. Springer Science and Business Media B.V., Formerly Kluwer Academic Publishers B.V. Retrieved September 20, 2005 from SpringerLink database.
2 Meinig, C., Stalin, S.E., Nakamura, A.I. and Milburn, H.B. (2005), Real-Time Deep-Ocean Tsunami Measuring, Monitoring, and Reporting System: The NOAA DART II Description and Disclosure. Retrieved September 20, 2005 from http://www.pmel.noaa.gov/tsunami/Dart/Pdf/DART_II_Description_6_4_05.pdf
3 Taverna, M. A.(2005, Jan 31). Back to the Future. Aviation Week and Space Technology, 162(5), 53. New York. Retrieved September 20, 2005,from ProQuest Research Library database.
4 Holton, C. (2005, April). A system of systems. Laser Focus World, 41(4), 59.Tulsa. Retrieved September 20, 2005,from ProQuest Research Library database
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