
CHAPTER 3
The Tsunami
3.1 General
Most large tsunamis arise around the rim of the Pacifi c Ocean and the
Indian Ocean, along seafl oor faults called subduction zones, where
colliding tectonic plates trigger large earthquakes (Folger 2012). Waves
spread in opposite directions from the fault and within minutes crash
onto nearby land, as in Japan in 2011; within hours crossing the ocean
and in this case sweeping a California man out to sea. Landslides and
volcanic eruptions can launch tsunamis in lakes and rivers. A warning
system consisting of a network of 53 detector buoys, most in the Pacifi c
Ocean, now tracks the movement of tsunamis, alerting ...