For residents of the san francisco bay area in California, their home is in one of the most agreeable parts of the world. The Bay Area has good weather, beautiful landscape, great job opportunities, and some of the most competitive and resourceful minds in the world to interact with. However, at the back of their minds is a phenomenon that can destroy the tranquility in Silicon Valley: earthquakes. The Bay Area sits on top of one of the most seismically active zones in the world. Crisscrossing the city, the valley and their neighbourhoods are seven geological fault lines. The great San Francisco earthquake of 1906 had released so much energy from the earth's bowels that it needed time to build up pressure again. So the 20th century was an unusually quiet period seismically. Geophysicists who study the area now say that this may have ended. "I think we are out of the earthquake shadow,' says David Schwartz, earthquake geologist at the US Geological Survey (USGS). "The Bay Area can now have a series of large earthquakes years or decades apart.' Economically, these earthquakes can have a disastrous effect on Silicon Valley. Experts estimate that even one earthquake from the about-to-explode Hayward Fault would be a disaster equal in magnitude