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Tectonic processes in the deep ocean occur over an immerse range of temporal and spatial scales. The shortest in time are from seconds to minutes during which earthquakes and landslides occur. The recurrence interval between earthquakes, submarine landslides, and volcanic eruptions may be tens, hundreds, or thousands of years. At the far end of the range are the tens of millions of years over which oceanic plates form at the spreading centers and drift, sometimes thousands of kilometers with speeds of a few centimeters per year, to the subduction zones. It is also over these long time scales that chains of volcanic islands and seamounts form and over even longer time scales that major asteroids may impact the Earth. These processes create a host of smaller-scale geological features, including rift valleys, earthquake fault scarps, submarine landslide deposits, and abyssal hills, which cover vast areas of the ocean floor. Using a wide variety of methods, scientists are developing a better understanding of these geological features and the processes that create them.