GEOL 2207 Lecture Notes - Longshore Drift, Wave Power, Megathrust Earthquake
Document Summary
Describe how tsunami form and how they are detected. Earthquakes, volcanic eruptions, meteor impacts, landslides, icebergs falling from glaciers. Dart system: measures pressure changes on seafloor, communicates info to warning centres. Explain how a tsunami differs from more common, wind-driven ocean waves. Short wavelength and period, breakers arrive and recede quickly. Tsunami: ultralong walvelength and period, huge mass of water comes ashore for several minutes. Vertical fault motion, energy transfer to water column, common in large subduction-related earthquakes. Identify tsunami warning signs, and know how to respond. Trough may arrive first, watch for receding sea level. Describe the risks from a tsunami for the coast of british columbia, especially one resulting from a megathrust earthquake. Define wave breaking, and determine when a wave will break. Waves become unstable, too high for wavelength. Wave energy becomes surf energy, turbulent mass of water rushing onshore.
