An earthquake is a natural phenomenon caused by seismic (sound) waves transmitted through the earth and causing the surface of the earth to tremble for a varying period of time. The degree of shaking can range from nearly undetectable to violent and devastating.
CQ Researcher, December 16, 1994.
Magill, Frank N., ed. Magill’s Survey of Science: Earth Science Series, 1990.
McGraw-Hill Encyclopedia of Science and Technology, 1992.
The New Book of Popular Science. Grolier, 1992.
Ritchie, David. The Encyclopedia of Earthquakes and Volcanoes, 1994. General encyclopedias
EBSCO Magazine Article Summaries
NewsBank and other newspaper indexes
Readers’ Guide to Periodical Literature
SIRS (Social Issues Resources Series)