The Bay Bridge in San Francisco didn't fare too well during the earthquake of 1989, when a portion of its upper deck collapsed onto the lower deck. A fissure in Loma Prieta created by the earthquake. Damage to a garage in the North Beach area, near Embarcadero. Damage to a wood-frame house in San Francisco's Marina district.

1989 Loma Prieta Earthquake At 5:04 pm on October 17th, 1989, a major earthquake occurred, its epicenter in the Loma Prieta area, south of San Francisco. It caused considerable damage to buildings in San Francisco, especially in the Marina district. Candlestick Park in San Francisco, where the Giants were about to play in the World Series, was shaken up pretty badly, and a few baseball fans were taken to the hospital. As people were trying to get into and out of the city, part of the Bay Bridge collapsed. In total, the Loma Prieta earthquake killed 63 people in the Bay Area. The rupture along the San Andreas fault was relatively minor compared to that of the 1906 San Francisco quake, only about 30 miles long in contrast to 1906's 270 miles. The focal depth of the quake, however, was unusually deep: 11 miles, as opposed to the typical California earthquake focal depth of 4 to 6 miles. The Marina district of San Francisco suffered some of the worst damage of this earthquake as a result of liquefaction. The 1989 Loma Prieta earthquake was a moment magnitude 7.0 (7.1 Richter), not considered even among the 15 largest earthquakes. Compared to the 3,000 casualties in the 1906 earthquake, the only 63 deaths in the 1989 quake, while still tragic, were the result of better building codes and more earthquake awareness. Although some of the casualties could have been avoided, such as by decreasing building on bayfill and retrofitting the Bay Bridge and other potentially unsafe structures, the Bay Area fared relatively well in the 1989 Loma Prieta earthquake. As in the 1906 San Francisco earthquake, liquefaction contributed to quite a bit of damage in the Marina district. Fortunately, not as many buildings were dependent upon the bayfill foundations, but damage was still maximum in the Marina district of San Francisco as well as portions of the East Bay, where fires broke out. A large section of the Bay Bridge's upper deck collapsed onto the lower deck during the earthquake, and the Embarcadero was badly damaged. Highways 1 and 101 were both closed due to landslides and unstable bridges. However, the most loss of life occurred on I-880 in Oakland. Over 40 slabs of concrete from the upper deck, weighing 600 tons each, collapsed onto traffic below. It took days to discover that 41 people had died in that incident alone. Much of the earthquake damage was limited to a few select areas. In many neighborhoods, there was almost no evidence that a major earthquake had even occurred. --by Alex Hoff �

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