5.1: A Concept of Time

• 5.1.1: Timeline of the Earth

  The Earth’s crust seems pretty quiet most of the time. Although we now know that the Puget Sound region is seismically active, you and I can drive from Portland, Oregon, to Vancouver, B.C., along Interstate 5 and never feel an earthquake. To make progress in understanding and forecasting earthquakes, we need to know how long it takes a fault to build up enough strain to rupture in an earthquake, and how large that earthquake is likely to be.