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.
This is called subduction. At subduction zones, where the downgoing plate bends and dives beneath the overriding plate, we get oceanic trenches. These are the deepest parts of the ocean. The Mariana Trench, located in the western Pacific, is the deepest trench of all. Scientists still know little about the bottom of the ocean, mostly because it is dark and hard to get to (we can't just get down there using SCUBA gear to look around).