In light of Tuesday's tsunami in Samoa and American Samoa, find
out how the killer waves are caused, what the warning signs are,
and how to respond when a tsunami threatens. A massive,
magnitude 8.0 undersea earthquake south of Samoa and American
Samoa sparked today's tsunami, according to the U.S. Geological
Survey. Scientists have found traces of an asteroid-collision
event that they say would have created a giant tsunami that
swept around the Earth several times, inundating everything
except the tallest mountains 3.5 billion years ago. The
coastline of the continents was changed drastically and almost
all life on land was exterminated. (Read the story.) An
earthquake generates a tsunami if it is of sufficient force and
there is a violent enough movement of the seafloor to cause
substantial and sudden displacement of a massive amount of
water. Tsunami (pronounced soo-NAH-mee) is a Japanese word, and
in fact tsunamis are fairly common in Japan. Many thousands of
Japanese have been killed by them in recent ce