Oakland, California Oakland to consistently be listed as one of America's most crime-ridden cities. In 1980 Oakland's black population reached its 20th-century peak at approximately 47% of the overall city population. The 6.9 Loma Prieta earthquake occurred on October 17, 1989. The rupture was related to the San Andreas fault system and affected the entire San Francisco Bay Area with a maximum Mercalli intensity of IX ("Violent"). Many structures in Oakland were badly damaged including the double-decker portion of Interstate 880 that collapsed. The eastern span of the San Francisco–Oakland Bay Bridge also sustained damage and was closed to traffic for one
1989 Loma Prieta earthquake about from the epicenter. From October 5, they reported that a substantial increase in noise was measured in the frequency range 0.01–10 Hz. The measurement instrument was a single-axis search-coil magnetometer that was being used for low frequency research. Precursor increases of noise apparently started a few days before the earthquake, with noise in the range 0.01–0.5 Hz rising to exceptionally high levels about three hours before the earthquake. Though this pattern gave scientists new ideas for research into potential precursors to earthquakes, and the Fraser-Smith et al. report remains one of the most frequently cited examples of a specific