According to Richard A. Trapp of the former Arizona Geological Survey, Tucson's earthquake zone classification is 2A.
A report prepared for Pima County Flood Control District, opens a new window (PDF) states "the Tucson metropolitan area straddles the boundary between Zone 1 and Zone 2A of the Seismic Zone Map of the Contiguous States (Uniform Building Code, 1994 and USACE ER 1110-2-1806, dated 31 July 1995) and thus is located in a region of low to moderate seismic potential."
The U.S. Geological Survey (USGS) is a good source for information about earthquakes. The USGS Earthquakes Hazards Program, opens a new window provides latest earthquakes, earthquake lists, maps, and statistics, and a searchable earthquake catalog.
Richard A. Trapp, Arizona Geological Survey. Mr. Trapp says Tucson's earthquake zone classification is from the 1994 Uniform Building Code. (Telephone call made by PCPL staff 09/27/2003.)
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