With hundreds dead in Indonesia from this weeks tsunami many are beginning to wonder about what happened to the much promised tsunami warning system. It does not help matters that less than two weeks ago UNESCO put out a press release that it was "up and running". Yesterday exposed the gaps that still exist and there is still much to be done.
Well, it's not so much the lack of or inefficiency of the very sketchy tsunami warning system currently still being put together in the indian ocean, so much as the fact that Indonesia, being an Island Arc subduction zone right along most of it's south and southwestern coasts, is right where the tsunamis are at - Any warning is still not warning enough, because the earthquakes happen in the subduction trench between 5 and 100 km offshore, right off the coast. In the deep water here, a tsunami can shift itself at speeds circa 800km/h, so in nearshore earthquakes, the tsunami strikes mere minutes after the 'quake, as they do not slow down until the water shallows, forcing the wave to pile up and slow. Tsunami warning systems, particularly ocean-wide systems, are primarily to give warning to those on the other side of the ocean, who may have ten to twelve hours to prepare. Whereas, those close to the earthquake centre in subduction zones such as Java, New Zealand, Japan, Chile, etc, have the added difficulty that even if the tsunami alarm system sounds (or even exists - there may not be a warning buoy between them and the epicentre), they have only a few minutes to realise what it is, get the message out, and get to higher ground. Generally, this is a recipe for panic. Where I spent most of the last two decades in Christchurch, New Zealand, we have well developed tsunami plans for tsunamis originating on the far side of the pacific, whereas for nearshore quakes off our own coast, the best advice our civil defence people can give is to kiss your arse goodbye, because the tsunamis will arrive 3 to 5 minutes after an earthquake on the TVZ subduction zone faults, and we don't have enough roads, vehicles, aircraft or time to do any sort of evacuation. And of course, natural mitigation might work, but the coastal homebuyers keep petitioning their councils to remove the sanddunes anyway.
One of the values of Appropriate Technology is that the systems should be made from local materials and be repairable locally.
Introducing mobile phone technology into poor rural areas as a tsunami warning system would be useful in the short term, but what happens when they start breaking? Are we making the communities dependent on foreign aid?
In many rural areas there are at least a couple of people with cell phones. (usually built and maintained regionally - esp. in india) After the 2004 tsunami I was surprised, although not shocked, to see villagers using sms to communicate with one another.
It has been kind of funny to be in a community meeting in east Sri Lanka and having to ask to borrow a cell phone to make a call. I am leaning toward a multi-level warning system rather than being dependent on one technology.