 Earth's lithosphere consists of several large tectonic plates, which slowly move towards and away from one another, either converging and subducting or diverging and rifting; volcanoes and earthquakes are generated by these activities.The west coast of North America is the site of plate margins between the large Pacific and North American plates, and also between the smaller Juan de Fuca and Cocos plates.Tectonic activity along the North Coast of British Columbia and Southeast Alaska is characterized by transform movements of the Queen Charlotte Fault, a plate boundary where the Pacific Plate skids by the North American Plate.