By now you probably know that yet another underwater earthquake has kicked up yet another tsunami that has struck yet another Indonesian island. At surf.bird.scribble, our hearts go out to the 50,000 Javans displaced and several hundred killed by the six-foot wall of water.
This latest disaster – and let’s not call it anything else, even if it was 1,000 times less devastating than the 2004 Indian Ocean tsunami, and never mind that foolish humans are killing each other in similar numbers on nearby continents – has sparked outrage over the continuing lack of a working tsunami warning system in the region.
God knows we could all use an early warning of a tsunami, but let’s just have a quick recap of the problem: What we’re trying to do is to notice a major earthquake happening deep in the Earth’s crust out in the middle of the ocean, and then issue some kind of panic alert that outraces the 500-mph tsunami wave and reaches only those coast-dwellers and sunbathers in the tsunami’s path.
Oh, and we have to deal with human nature, too. A 2005 earthquake off the U.S. West Coast sparked a formal tsunami alert for pretty much all of coastal California…and almost no one listened. The only folks that took it seriously were some (not all) of the residents of Crescent City, a NorCal town that learned its lesson in 1964, when it was hammered by a tsunami from the magnitude 9 Good Friday earthquake in Alaska.
In 2005, I was in Santa Cruz, approximately 13 feet above sea level, and I didn’t hear about the tsunami warning until the news reported that it had been lifted. And there I was in the most insanely connected state of the wired-to-the-gills United States. Yesterday’s earthquake was only about 270 km off Java, and the tsunami arrived in about a half-hour. So I’m not saying we shouldn’t try to give warnings, I’m just saying the problem needs a lot of work.
Good old NOAA is doing its best to protect the Pacific coast of the U.S. They’ve deployed a dozen special tsunami-measuring devices in key parts of the ocean. (They’re called tsunameters. more about them here) A sensitive pressure recorder sits on the ocean floor and somehow detects the pressure from a tsunami wave passing several miles overhead. When and if this happens, the tsunameter beams an alarm to a nearby buoy, which forwards the news by satellite to a NOAA desk, where, as I imagine it, a red light starts flashing, people start shouting at each other, and someone calls the President.
In the meantime, NOAA is trying to get the word out to residents of the Pacific Northwest that they are sitting more or less at the end of a shotgun barrel. The Cascadia subduction zone lies less than a hundred miles off Washington and has a history of producing major tsunamis. The last one was in 1700, when it pitched a tsunami at Japan big enough to make their history books.
Like the Java tsunami, a tsunami from Cascadia would hit Washington and Oregon in 30 minutes or less. Unlike the 7.7 quake off Java, the Cascadia fault could be in the magnitude 9 range, or some 50 times more powerful. In that case, I take heart in NOAA’s last-ditch warning method: “If you feel violent shaking for several minutes, head for higher ground. The earthquake is your warning.“
(more tsunami resources from a Woods Hole page I put together)