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Dziak, R.P., J.H. Haxel, H. Matsumoto, T.-K. Lau, S. Heimlich, S. Nieukirk, D.K. Mellinger, J. Osse, C. Meinig, N. Delich, and S. Stalin (2017): Ambient sound at Challenger Deep, Mariana Trench.Oceanography, 30 (2), doi:10.5670/oceanog.2017.240.
You might imagine the bottom of the ocean’s deepest point, seven miles down, to be a very quiet place. However, NOAA and partner scientists, making the first recordings from the Challenger Deep trough in the Mariana Trench in the Pacific Ocean, found something remarkably different: a wide variety of human-caused and natural sounds, including the hum of ship propellers, active sonar, earthquakes, baleen whales, and a category 4 typhoon passing near the sensor.
Human-generated noise has increased steadily over the past several decades. This project, which was funded by the NOAA Office... more »
Dziak, R.P., D.R. Bohnenstiehl, E.T. Baker, H. Matsumoto, J. Caplan-Auerbach, R.W. Embley, S.G. Merle, S.L. Walker, T.-K. Lau, and W.W. Chadwick, Jr. (2015): Long-term explosive degassing and debris flow activity at West Mata submarine volcano. Geophys. Res. Lett., 42(5), doi:10.1002/2014GL062603.
Even though ~75% of Earth's volcanic activity occurs below the sea surface, many questions remain on the longevity and acoustic characteristics of explosive seafloor eruptions. To date, only two active eruptions have ever been observed visually in the deep-ocean (>500 m) volcanoes, and then only over time periods of hours to days. The discovery of the actively erupting West Mata volcano in the NE Lau Basin near Samoa offered a rare opportunity to investigate a deep-ocean, explosive eruption. Video images of West Mata collected by remotely operated vehicle (ROV) provided unprecedented... more »
Matsumoto, H., D.R. Bohnenstiehl, J. Tournadre, R.P. Dziak, J.H. Haxel, T.-K.A. Lau, M. Fowler, and S.A. Salo (2014): Antarctic icebergs: A significant natural sound source in the Pacific Ocean. Geochem. Geophys. Geosyst., 15, doi: 10.1002/2014GC005454.
Previous research indicates that low-frequency ocean noise levels have risen 3 to 4 times since the early 1960s in some areas. This rise has been largely attributed to increased global ship traffic. The scientific community has become increasingly concerned about the adverse effects of anthropogenic (human-made) inputs to the marine ecosystem, and in particular to marine animals, which rely on sound to aid in migration, feeding, and breeding.
PMEL’s Acoustics Program has been monitoring the low-frequency acoustic... more »
Toomey, D.R., R.M. Allen, A.H. Barclay, S.W. Bell, P.D. Bromirski, R.L. Carlson, X. Chen, J.A . Collins, R.P. Dziak, B. Evers, D.W. Forsyth, P. Gerstoft, E.E.E. Hooft, D. Livelybrooks, J.A . Lodewyk, D.S. Luther, J.J. McGuire, S.Y. Schwartz, M. Tolstoy, A.M. Tréhu, M. Weirathmueller, and W.S.D. Wilcock (2014): The Cascadia Initiative: A sea change in seismological studies of subduction zones. Oceanography, 27(2), doi:10.5670/oceanog.2014.49, 138-150.
There is increasing scientific and public awareness that the Cascadia subduction zone, an active plate boundary fault off the coast of the Pacific Northwest (PNW), is capable of generating great earthquakes (magnitude 9 or larger). Concern over the earthquake hazard of this zone motivated creation of the Cascadia Initiative, an NSF sponsored community project to deploy and maintain an array of onshore/offshore seismic and geodetic sensors. PMEL scientists are co-investigators on the project and have led four oceanographic expeditions to collect data from the seafloor seismic components of... more »