Earthquakes and volcanoes are among Earth’s most spectacular and
terrifying geological events. The Mount St. Helens eruption of 1980
and the Haiti (7.0 magnitude) and Chile (8.8 magnitude) earthquakes
of 2010 are recent and memorable examples of the extreme power
that often accompanies these events. The Indian Ocean tsunami of
2004 was caused by an underwater earthquake that is estimated to
have released the energy of 23,000 Hiroshima-type atomic bombs, and
caused the deaths of more than 150,000 people.