Seafloor topography data & subterranean conceptual view at Kermadec Trench

Ocean trenches, such as the Kermadec (shown here) near New Zealand, exist where one of Earth’s tectonic plates is sinking and sliding beneath another. This process, referred to as plate subduction, forms many of the deepest places in the oceans , and also produces the most tectonically active settings on Earth, the so-called subduction zones of the overriding plate above trenches. Subduction zones also host long chains of active volcanoes as well as over 90 percent of all earthquakes, including many of the largest and most destructive earthquakes on record, such as the magnitude 9.0 off the coast of Japan in 2011 that spawned a massive tsunami. Learn more about what is known and unknown about trenches and why they are so difficult to explore in a free public event at WHOI on Saturday, August 24. (Illustration by Jack Cook and E. Paul Oberlander, © Woods Hole Oceanographic Institution)