The average starting wage of an apprentice is about 50% of a journey worker's rate of pay. Programs are required to progressively increase the apprentices wages provided the on-the-job training and school performance is satisfactory and in accordance with apprenticeship committee.
The Aleutian Trench formed as the Pacific Plate converged with the North American Plate forcing the Pacific's oceanic plate into the mantle because the Pacific Plate is denser than the North American Plate. The Aleutian Trench and other Trenches formed a subduction zone by converging with other plate tectonics.
Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. Because of this the continents ride on the denser oceanic plates. The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. The layer below the rigid lithosphere is a zone of asphalt-like consistancy called the Asthenosphere.