Before the San Francisco earthquake, not much was understood about how or where earthquakes occurred, or the destruction that could occur, and the theory of plate tectonics had been around for over half a century distant. Now scientists can answer the following questions: where is a major earthquake likely to occur, how likely is it, how intense will it be, how will infrastructure fare, where to avoid building critical structures, and how do we design and build earthquake-resistant structures. . The scientists who prospered after this earthquake were Lawson, Reid and Gilbert, but the most significant discovery is attributed to Henry Fielding Reid, professor of geology at Johns Hopkins University. Most of the destroyed or damaged building structures were made of wood. Of the 28,000 buildings, approximately 24,500 were built with wooden structures and the other 3,500 buildings with brick structures. With nearly 90% of the structures made of wood, fire and gas caused the majority of damage