EARTHSC 2GG3 Lecture Notes - Lecture 8: Seattle Fault, Island, Warning System
Document Summary
Lecture 8, september 23, 2013: historical tsunami. An estimated 1200 km of fault slipped about 15 m along the subduction zone (indian and burma plates) over a period of several minutes. The waves devastated the shores of the ocean. Coastal residents should be aware of danger signals for tsunami, including earthquakes and a rapid rise or fall in sea level: once these signs are noticed, inhabitants should run upslope or drive directly inland. Permits waves to penetrate without building higher: reinforce shoreline with well-rooted trees that permit water to flow between them and slow wave, prediction: future mega-tsunami, large ditch or reinforced concrete wall can reduce impact of first wave. Tsunami from major pacific coast subduction earthquakes occur every few hundred years and reach shore within 20 minutes of the quake. The record of subduction zone tsunami is based on sand sheets over felled forests and marsh vegetation pushed into coastal bays.