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Seismic safety database for California


California Watch, a project of the Center of Investigative Reporting, has built an interactive database of schools located in seismic hazard zones for the public. It also mapped the public K-12 schools in the state and those without seismic-safety certification under the Field Act, California’s building standards for school construction.

The project started by obtaining digitised maps from the California Geological Survey, which tracks state-designated fault zones. The state law that defines these fault zones was enacted in 1972, a year after the devastating Sylmar earthquake in the San Fernando Valley. The law, known as the Alquist-Priolo Earthquake Fault Zoning Act, restricts most construction within these seismic zones.

Under the law, high-occupancy buildings – such as schools, hospitals and commercial projects – must be set back from an active fault, generally at least 50 feet. To the state, an active fault is defined as one with evidence of earth movement within the past 11,000 years. The state keeps the maps in quadrants – more than 700 of them. California Watch stitched together each quadrant to cover the entire state. After overlaying about 10,000 public schools tracked by the California Department of Education, it found about 90 schools that appeared to be located within these active fault zones.

The project examined U.S. Geological Survey data of earthquake faults in California. The data includes faults that are believed to have caused earthquakes greater than magnitude 6.0.

The database of public schools provided by the California Department of Education included latitude and longitude points, which made mapping possible. California Watch had to identify and add mapping coordinates for some of these schools. The new database allowed it to look for schools inside seismic zones in a way that previously could not be done.

Source: California Watch