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Don’t Look Behind You

July 29, 2012

Water is vital to all known forms of life on Earth, but it also plays a fundamental role in processes deep beneath the seafloor. Water in Earth’s mantle enables tectonic plates to move and drives mantle melting and volcanism—processes that create and sustain the continents and atmosphere. In early 2012, WHOI’s Dan Lizarralde, Nathan Miller, and Helen Feng sailed on the research vessel Marcus Langseth, towing air guns (shown here) over the Mariana Trench, a place where water trapped in the subducting Pacific Plate is being recycled into mantle. Sound energy from the air guns traveled about 20km (12 miles) beneath the seafloor and was recorded by ocean bottom seismometers 400km (250 miles) away. The scientists are using the data to create images of the subducting plate, which will help them understand how much water is recycled into the mantle at subduction zones and how water becomes trapped in subducting plates. (Photo by Nathan Miller, Woods Hole Oceanographic Institution)