Ocean Floor Subduction

In fact this area has seen the eight most powerful earthquakes ever recorded and is home to over 75 percent of the world s active and dormant volcanoes.

Ocean floor subduction. Not only is oceanic crust continually created at mid ocean ridges but it is also continually re absorbed into the mantle at subduction zones which are marked by deep ocean trenches. A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle. Therefore seafloor dating isn t that useful for studying plate motions beyond the cretaceous. No earthquakes have been observed or reported from the shallow aseismic zone of the north japan trench.

The mariana trench the world s deepest submarine de pression is more than 11 000m below sea level in some parts about 7 000m below the mean depth of the. For that geologists date and study continental crust. These boundaries mark the collision between two of the planet s tectonic plates. Sea floor spreading and subduction work together.

A subduction zone is the biggest crash scene on earth. They move the ocean floor as if it were on a giant. These age data also allow the rate of seafloor spreading to be. The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century.

Samples collected from the ocean floor show that the age of oceanic crust increases with distance from the spreading centre important evidence in favour of this process. The process by which ocean floor sinks beneath a deep ocean trench and back into the mantle is called subduction sub duk shun. Basalt the once molten rock that makes up most new oceanic crust is a fairly magnetic substance and scientists began using magnetometers to measure the magnetism of the ocean floor in the 1950s what they discovered was that the magnetism of the ocean floor around. Regions of smooth ocean floor subduction are correlated with typically large under thrust earthquakes within the deeper part of the plate interface zone.

The plates are pieces of crust that slowly move across the. Regions where this process occurs are known as subduction zones rates of subduction are typically measured in centimeters per year with the average rate of convergence being. The process by which oceanic crust sinks beneath a deep ocean trench and back into the mantle at a convergent plate boundary. As upwelling of magma continues the plates continue to diverge a process known as seafloor spreading.

Plate tectonics plate tectonics seafloor spreading. Subduction caused volcanism and earthquake activity occur frequently along the outer edges of the pacific ocean in an area known as the pacific ring of fire.