A stroke is a brain attack â a sudden interruption of blood flow to part of the brain causing it to stop working and eventually damaging brain cells. The effects can be devastating and may last a lifetime. A stroke is also known as a cerebrovascular accident (CVA). There are several different types of stroke, with different causes. Ischaemic stroke: This is the most common type of stroke, particularly in older people.
Examples of some deep ocean trenches that are subduction zones are off the West coast of South America, in the Peruvian Trench. The Aleutian Trench, in the North Pacific Ocean, and the deepest, most famous one in the world, the Marianas Trench off the coast of the Marianas Islands in the Southeast Pacific.
As the plates continue to press against one another, the ocean plate gradually sinks beneath the continental crust and re-enters the mantle. According to Live Science, the deepest known ocean trench is the Mariana Trench, located in the Pacific Ocean. It is approximately 1,500 miles long. The deepest portion of the Mariana Trench is the Challenger Deep, a narrow portion at the southern end, which is roughly 36,000 feet deep. The water temperature in this area is slightly above freezing.The world's ocean trenches remain largely unexplored due to the immense pressures at such depths.