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Probing the Seafloor with Sound

April 5, 2018

To probe the seafloor, scientists send sound waves down through the ocean and seafloor and record reflected echoes with ocean bottom seismographs and hydrophones trailing behind a ship. The time it takes for the sound to return allows scientists to determine the composition and structure of the material the sound wave travels through. Hannh Mark, a graduate student in the MIT-WHOI Joint Program, used sound wave data to detect the olivine crystalline structure of rocks in Earth’s mantle as magma at mid-ocean ridges rises. The research offers a more detailed picture of how ocean crust forms and how Earth’s tectonic plates move. (Illustration by Natalie Renier, Woods Hole Oceanographic Institution)