Interesting infos raked up on the internet:
Tsunami Warning System Not in Place
Thursday, December 30, 2004
By Colum Lynch The Washington Post
UNITED NATIONS--An international agency that monitors nuclear explosions around the world almost certainly picked up immediate signs of the underwater earthquake and tsunami in Southeast Asia on instruments it operates around the Indian Ocean, but it had no chance to alert governments in the region because its offices were closed for the holidays, according to a spokeswoman.
The information from the Comprehensive Test Ban Treaty Organization's network may yield insights into the catastrophe but would not have been critical in saving lives because there is no functioning system capable of channeling early warnings to regions struck by the tsunami, said earthquake and tsunami experts. Still, the agency's failure to react during one of the most momentous seismic events in decades has proven embarrassing, officials said.
Daniela Rozgonova, a spokeswoman for the Vienna-based agency, said raw data from its seismic and hydroacoustic monitoring stations in the region would be reviewed by analysts when they return from vacation Tuesday.
But she insisted that a team of about 100 analysts at the agency's International Data Center in Vienna would not have been able to get a warning to tsunami victims even if they had been at work. ``The whole system has not been set up to warn for natural disasters,'' she said. ``It's not set up for it.''
The test ban organization is constructing an international network of more than 320 monitoring stations to detect whether countries are conducting underwater or atmospheric nuclear tests. Although the system is not fully operational, there are 175 functioning stations, including several in and around the Indian Ocean that can detect seismic and underwater signals. When its analysts detect an unusual seismic disturbance, they send preliminary bulletins to dozens of member states in one to three hours. A more comprehensive report is issued within 24 hours.
Bernard Massinon, a French seismologist who is a scientific adviser to the test ban organization, said the agency's seismic stations--including eight in Indonesia, Thailand and Sri Lanka--could technically be linked to an early warning system for earthquakes and tsunamis if member states decided to do so.
``Could we help by providing real time data from this network?'' he said. ``The answer should be yes.''
Still, geoscientists said there was no shortage of instant data from other sources indicating that a massive earthquake had struck off the coast of Indonesia and could potentially generate a large tsunami. Seismic stations on the other side of the globe immediately detected a major quake, and Australia, which operates a tsunami warning center, issued an alert about a half an hour after it occurred.
``They could tell exactly where it occurred instantly, and they probably knew right away there was a big tsunami generated by this an hour or two before these waves hit Sri Lanka,'' said John Clague, an expert on earthquakes at Simon Fraser University in Vancouver, Canada. The problem, he said, is that ``there is no infrastructure to communicate it.''
``There is already a global network that monitors earthquake activity and reports almost immediately on the occurrence of a major earthquake,'' said Harold Mofjeld, a senior scientist in the tsunami research program of the U.S. National Oceanographic and Atmospheric Administration. He said the test ban organization's data ``in principle could be integrated into an operational early warning system.''
The Indian Ocean has little of the latest technology that is used to detect and track tsunamis in the Pacific Ocean, where they occur more frequently. Scientists use an array of devices to do this, including costly deep water pressure sensors that detect the movement of waves.
Massinon said the test ban agency's three Indian Ocean hydroacoustic stations on Diego Garcia Island; Cape Leeuwin, Australia; and the French-owned Crozet Islands have limited value in predicting the course of a tsunami.
Outside specialists said that the acoustic measurements might be useful in assembling computer models of tsunami behavior but that it would not have made much of a difference in the disaster.
``The hydroacoustic stations probably recorded a lot of energy radiated by the main earthquake and its aftershocks, but those signals wouldn't give a clear indication of whether a tsunami was likely or not,'' said Jeffrey McGuire, assistant scientist for geology and geophysics at the Woods Hole Oceanographic Institution in Massachusetts.[*]
Jan Egeland, the United Nations' top humanitarian aid official, said the crisis has fueled interest in creating an early warning system for the Indian Ocean. He said that governments at an upcoming U.N.-sponsored meeting on natural disasters in Kobe, Japan, would discuss the issue.
Salvano Briceno, director of the U.N. International Strategy for Disaster Reduction, called for speedy action to develop such a system. ``I want to see that every coastal country around South Asia and Southeast Asia has at least a basic but effective tsunami warning system in place by this time next year,'' he said. ``There is no reason this cannot be done.''
``Clearly, there wasn't a proper warning system in place for that part of the world,'' President Bush said Tuesday. ``And it seems to me it makes sense for the world to come together to develop a warning system that will help all nations.''
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[*]A somewhat dubious opinion by "geonerd" McGuire since hydroacoustic signals are used to discriminate --that is, tell-- an underwater nuclear explosion from a natural earthquake:
Could the event that day in the Indian Ocean be a nuclear explosion? Figure 4 indicates four IMS stations that acquired data; another three stations in North America also detected this very small event, whose yield, if it were nuclear, would be on the order of a hundred tons of TNT equivalent. The best way to tell if this was an earthquake or an explosion, would be to look at the hydroacoustic record for the IMS station in the middle of the Indian Ocean - a huge hydroacoustic signal would be expected at this location from any Indian Ocean explosion bigger than one ton in the water column — but that station is not yet installed. We can still have confidence that this is an earthquake and not an explosion, because the two seismographic stations in Africa (BOSA and BGCA) and the one in Thailand (CMAR) all recorded seismic surface waves — which a small nuclear explosion would not generate.
[...]
earthinstitute.columbia.edu
Also worth a look:
ctbtcommission.org |
