Plate Tectonics Plate Tectonics is theory of global tectonics that has served as the master key in modern geology for understanding the structure, history, and dynamics of the earth's crust. The theory is based on the observation that the earth's solid crust is broken up into a dozen semirigid ...

Understanding the Loma Prieta Earthquake:10 Years LaterAt 5:04 PM on October 17, 1989, the San Francisco Bay Area was severely shaken for 15 seconds by the Loma Prieta earthquake located to the south on the San Andreas fault near Santa Cruz. Although the quake did not tear the ground surface, it co...

Studying Seismic ActivityCalifornia has 200 or more faults capable of producing large earthquakes. Some of the faults are hidden and some visible at the surface. The biggest concentration of faults are in the San Adreas fault zone and the San Jacinto fault zone. Because of California's large amou...