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To get around this, tsunami watchdogs have turned to sensors that sit on the seafloor and detect the feathery touch of a tsunami passing overhead. Japan has laid a series of such bottom-pressure sensors along a cable stretching out from its coastline. Now the National Oceanic and Atmospheric Administration (NOAA) in the United States is adding bottom sensors to its warning system. When the sensors pick up a tsunami, a buoy anchored nearby relays the message to shore via satellite. Depending on where the tsunami originates, the sensors could give hours of warning time. (See Tsunami spread animation, below.) They could even help people on the U.S. West Coast after an earthquake on the Cascadia fault, which lies minutes away in tsunami travel time. Though minutes of warning may not be enough in all cases, NOAA's Frank Gonzalez, the scientist heading the sensor project, still thinks the buoys are better than nothing. "A minute or two of warning will get you down the road another half mile and you'll be safe," he says. During the 1993 tsunami attack on Okushiri, Japan, Gonzalez says, "there were a number of incidences in which people were educated enough about tsunamis that they were out the door and up the hill in their pajamas within minutes of the warning, and it saved their lives."
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