Land Feature - Pacific Northwest

Land Feature - Pacific Northwest

The Pacific Northwest region of the United States is an area of significant tectonic activity. The theory of plate tectonics is illustrated in the tectonic activity of the Pacific Northwest. The geological events triggered by plate tectonics shaped the region and caused major land features. The study of rocks can give vast amounts of historical information about the geological events that have taken place over time in the Pacific Northwest.

Plate Tectonics

Plate tectonics the theory that the Earth's crust is comprised of plates (Merali & Skinner, 2009). This theory is supported by hundreds of years of research, including the theory of continental drift. Continental drift states that the plates of the earth's crust, or lithosphere, are constantly in motion (Merali & Skinner, 2009). It also theorizes that the continents were connected at one time in a huge land mass called Pangaea. The movement of the plates is partially because of the motion a layer of hot, ductile rock below the lithosphere, known as the asthenosphere (Merali & Skinner, 2009). A plethora of information has been collected to explain the movement and interactions of the Earth's plates.

The Earth's plates interact with each other in three basic ways. They collide, split apart, and slide past one another (Merali & Skinner, 2009). These actions, which mostly occur along plate boundaries, generate a large amount of earth changing activity, such as earthquakes and mountain building (Merali & Skinner, 2009). The theory of plate tectonics also expounds on the location deep ocean trenches and mountain ranges, and the distribution of earthquakes and volcanic activity (Merali & Skinner, 2009).

Earthquakes and Volcanoes

The factors that influence earthquakes and volcanic activity in the Pacific Northwest region of the United States can be explained by the theory of plate tectonics. Earthquakes and volcanic activity occur primarily along plate margins. These activities are a constant reminder of the immense energy of plate tectonics. Earthquakes occur along faults, much like the fault along the coast of the Pacific Northwest, where tectonic plates are converging. In this region, one plate is sinking beneath another as they come together in a process called subduction (Merali & Skinner, 2009). The deepest and most powerful quakes occur in subduction zones (Merali & Skinner, 2009). The physical location where the earthquake originates can at depths from a few kilometers to several hundred kilometers below the ground surface (Merali & Skinner, 2009). The subduction zone is also an ideal location for volcanic activity. A long chain of volcanoes in the Pacific Northwest is located parallel to the convergent plate boundary (Merali & Skinner, 2009).

Earthquakes