The February tsunami in Chile caught coastal villages unprepared
[SANTIAGO, CHILE] An undersea observatory linked to a fibre optic cable could warn people in advance of a coming tsunami and help prevent casualties, such as those seen in the aftermath of last February's earthquake off the coast of Chile.
Chao-Shing Lee, a biophysicist from the National Taiwan Ocean University, and Victor Gallardo, a researcher from the University of Concepción, Chile, presented the technology last month (13 August) to a special commission of the Chilean Parliament which is investigating the country's response to the February earthquake that claimed around 500 lives.
"The marine cable consists of an optical fibre system connected to a variety of sensors and other instruments able to detect changes in the sea floor distinctive of a tsunami," Gallardo told SciDev.Net.
Optical fibre allows quick data transmission over long distances with no loss in resolution or accuracy. "The information is automatically sent to land at the speed of light. Simulations have shown that you can detect a tsunami that originates some 200 miles off the coast up to 20 minutes before it hits the land," Lee told SciDev.Net.
"This is extremely important because national authorities have time to shut down important equipment and send an alert to people on the coast," he added.
Currently, scientists rely on a global seismometer network to detect earthquakes that might trigger tsunamis. Deep-ocean pressure sensors and coastal tide gauges are the only tools available to detect and measure a tsunami.
The earthquake in Chile knocked out all communications and the country's navy — in charge of issuing warnings — was not aware the tsunami was approaching. Government authorities heard about it only after it had devastated many places.
"Japan is already deploying this technology [in DONET – Dense Oceanfloor Network System for Earthquakes and Tsunamis]; Canada and the United States have completed nearly 90 per cent of a system on their west coast, and Taiwan will have its first cable system, called MACHO [Marine Cable Hosted Observatory], next year."
A drawback is the high cost, said Gallardo, but added that the cost would be worth it because of the lives and goods that could be saved, and help it would provide for fisheries and marine research in general. "TV cameras and sensors can monitor fish and currents passing near the cable to help understand the ocean environment and fish stocks," he said.
"Chile should have one or more cabled ocean observatories to provide real-time data on seismic activity and tsunamis," said Chris Barnes, project director of an undersea observatory NEPTUNE Canada (The NorthEast Pacific Time-Series Undersea Networked Experiments). "The data return is much faster than tsunami waves and so warnings can alert local communities, assuming they are connected to the Internet and have a local warning system for disseminating information."
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