One big incentive for deploying the instruments is that they will provide a way to image the Earth's insides, using the waves of energy sent from faraway earthquakes to make a geological map of the rocks that comprise the Cascadia fault. "We expect to be able to hear magnitude 6.5 earthquakes - and above - from around the world, as well as local earthquakes," Barclay told OurAmazingPlanet. The instruments, which resemble stooped pyramids, will not give up their secrets until a year from now, when scientists return to wrestle the devices off the seafloor, crack them open and see what data are captured inside. Scientists and technicians ready an ocean bottom seismometer for its trip to the seafloor off the coast of Washington. They will serve as silent sentinels, taking a torrent of data on the Earth's movements - whether minute or massive - at a rate of 125 samples per second. The devices, armed with seismometers and other sensing equipment, are spaced more than a mile apart in a line that marches out to sea. The first instrument stands about 15 miles offshore. In late July, researchers spent more than a week aboard a research vessel, hoisting the 1,500-pound instruments overboard and, with the help of very long cables and a sturdy crane, settling each massive sensor on the seafloor.
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