Local Geology
While studying the 1906 earthquake, members of the State Earthquake Investigation Commission noticed how certain types of soil and rock caused more shaking than others(Report of the State Earthquake). In San Francisco, the most shaking occured in China Basin and the Marina District - both soft sedimentary soils(National Earthquake). These areas would also sustain the most damage during the Loma Prieta earthquake of 1989.
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Types of Soil/Rock in California
On a scale from 1 to 5, 1 least prone to shaking, 5 most prone to shaking
(National Earthquake Hazard)
Map of Shaking in California(Lawson Report 1908)
Using Our Knowledge Of Local Geology
When we know what types of soils will exprience the strongest shaking, we can avoid building important structures in these areas. People who wish to live in less earthquake-prone areas may find it easier to do so(Finch pers. comm.). The discovery of the connection between local geology and earthquakes has also made it easier to know where a strong earthquake might strike("United Staes Geological Survey").