Ah, plate tectonics, fascinating stuff. The whole surface of the earth is on the move, and at the boundaries between moving crustal plates we always find major volcanic activity, earthquakes, and mountain building going on. The mountains that extend from Yukon all the way down the west coasts of both North and South America were pushed up by the collision of the continents with the Pacific Ocean floor. Many things can happen at a boundary between crustal plates: one dives under the other, which produces deep ocean trenches like the ones we find east of the Japanese islands; or they just crash into each other and buckle the crust up, which is what happened when India crashed into Asia and pushed up the Himalayas; or they pull apart and create huge cracks like the Great Rift Valley of north eastern Africa.
What's happening geologically on Canada's west coast is a boundary collision event related to the famous San Andreas fault that rattles California every century or so. The whole story is long and complex, but the essence of it is that the Atlantic is opening up and the Pacific is closing, each getting wider and narrower respectively. The hot springs at America's Yellowstone National Park and around Banff in Canada, Mount St. Helens, and the earthquake danger on the west coast of North America, are all related to the movement of crustal plates and the activities that happen at their boundaries.
Better stop now, I could go on for dozens of pages about this... Google for "plate tectonics" and follow whatever links appeal to you, you'll learn more than you ever wanted to know about earthquakes, volcanoes, mountains, and valleys.
