GEOLOGY

Detailed explanation-1: -In particular, ocean trenches are a feature of convergent plate boundaries, where two or more tectonic plates meet. At many convergent plate boundaries, dense lithosphere melts or slides beneath less-dense lithosphere in a process called subduction, creating a trench.

Detailed explanation-2: -Trenches are formed at subduction zones on a convergent plate boundary.

Detailed explanation-3: -At an ocean-ocean convergent boundary, one of the plates (oceanic crust and lithospheric mantle) is pushed, or subducted, under the other (Figure 4.6. 1).

Detailed explanation-4: -Oceanic-Oceanic Convergent Boundary At a convergent boundary between two plates of oceanic lithosphere, the older, denser oceanic plate will always subduct, which will cause earthquakes and form volcanic isles.

Detailed explanation-5: -Pacific Rim Convergent plate boundaries are found around much of the Pacific Ocean basin. Trenches mark subduction zones. Volcanoes are found in an arc above those subduction zones. The Cascades (Figure below) are a chain of volcanoes at a convergent boundary.