Schussler ensured that each block of the dam was poured with concrete made to the exact proportions of his mix specifications . The dam has survived both the 1906 San Francisco earthquake and the 1989 Loma Prieta earthquake — despite its location about 100 yards east of the San Andreas Fault . It was subject to severe shaking in both earthquakes
1989 Loma Prieta earthquake
1989 Loma Prieta earthquake
Crystal Springs Dam