A building in downtown San Francisco damaged in the 1906 quake. This fissure was a result of the 1989 Loma Prieta earthquake. Damage on East Howard Street after the 1906 earthquake.

San Jose Introduction Have you ever considered how your city could withstand an earthquake? This is a crucial question to think about if you live in California because California is considered "Earthquake Territory." In particular, the San Francisco Bay Area is very vulnerable to earthquakes. San Jose usually is not the epicenter of earthquakes, but that does not mean that the city does not get shaken! San Jose is located southeast of San Francisco. Nearby Faults Two major fault systems are located near San Jose. The San Andreas Fault system and the Hayward Fault system. The San Andreas Fault system is located to the west of San Jose. The Hayward Fault system is located to the east of San Jose. San Jose is pretty much surrounded by the major fault systems of Northern California. The San Andreas Fault is very active. I'm sure you remember one of the most memorable earthquakes in Northern California, the 1906 San Francisco earthquake. It was recorded that more than 3,000 people died. 102 of the deaths occurred in and near San Jose. Another well-known earthquake was the 1989 Loma Prieta earthquake. According to the 1990 studies by the United States Geological Survey (USGS), there is a good chance that the next big earthquake on the San Andreas Fault system could occur near San Jose. It is said that the earthquake will cause greater damage compared to the 1989 Loma Prieta earthquake, because of the increase of population. � The 1868 Hayward earthquake extended from San Jose to San Pablo Bay, 74 miles northward. The 1868 earthquake had a magnitude of an M7.0. More than 60 people died, plus, there were over 3,000 injuries. Damage Towards Buildings Most modern buildings are safe during an earthquake (most modern buildings are built to seismic standards). Damage during an earthquake can result from the strength of the shaking, the length of the shaking, the type of soil that the buildings are founded on, and the type of buildings that were built. The strength of the shaking increases as the distance of the earthquake decreases. Depending on how the fault breaks during an earthquake factors how long the earthquake will last. Greater damage occurs to the buildings that shake the longest. Bayfill mud is a type of substrate that causes a lot of shaking because the soil is soft, thick, and wet, therefore, making the ground unstable during an earthquake (the shaking is increased). A big problem for San Jose and San Francisco areas is liquefaction. Because San Jose is located on bayfill, the San Jose State Marine Station, (located in Moss Landing) was damaged by liquefaction. For residential structures, structures of wooden-frame construction have performed well in past earthquakes because they tend to be light. Some major exceptions are older structures (pre-1940s), irregular shaped newer homes, and multi-story apartment buildings (or houses). Other Information There have been at least four earthquakes in San Jose (meaning that the epicenter was located in San Jose). All of them had magnitudes between M5.5-M6.5. --by Margot Mansfield � � � �

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