GG231 Chapter Notes - Chapter 3: Mathematical Model, Subduction, Lesson Learned
Document Summary
December 2004 countries around indian ocean. Chapter 3: 230 000 people killed, hundreds of thousands injured, millions displaced, source was from magnitude 9. 1 quake off sumatra. Tsunami"s are produced by the sudden displacement of ocean, lake or river water. Triggers = large quake, landslide, explosive volcanic eruption, impact in the ocean. Quake can cause tsunami by displacing ground or by triggering landslides: displacement more common block of earth"s crust moves up or down. Takes m > 7. 5 to trigger damaging tsunami. 4 stage process: displacement of seafloor transmits outward and upward from source via oscillatory waves. Waves intercept surface and spread outward like ripple: @ deep ocean, waves move more rapidly and are spaced far apart. @ deep ocean velocity = 720 km/h. Wave crests far apart and only 1 m high not noticeable. @ near land, water depth and velocity decrease, space between wave crests decrease, height increases.
