GEOL 2207 Lecture Notes - 2002 Denali Earthquake, 1964 Niigata Earthquake, Trans-Alaska Pipeline System
Document Summary
Dense rock (bedrock) transmit earthquake energy quickly. Slow down in heterogeneous rocks, unconsolidated sediment and sediment with high water content. Amplification occurs when energy transferred from p and s waves to surface waves as they slow. Increases when speed of earthquake energy slows down. Richmond and delta and areas around fraser river. More damage can occur in areas further away from epicenter depending on local ground conditions. Clays (lake sediments up to 40m thick) amplified motions up to 50x compared to adjacent solid rock. Displacement along the fault causes cracks in surface and fault scarps. Lot of money in california spent in planning. Causes damage to buildings, bridges, dams, tunnels, pipelines, etc. Sand layers turn from solid to liquid, causing buildings and land to sink. Occurs in young lose, water saturated sediments: water pushed out between pores, and becomes liquid, makes sand volcanoes when water reaches to surface. The 1964 niigata earthquake (7. 5m) liquefied the soil beneath apartment buildings.
