ypical geologic investigations of active earthquake fault zones require that the fault can be observed at or near the Earth’s surface. However, in urban areas, where faults present a direct hazard to dense populations, the surface expression of a fault is often hidden by development of buildings and infrastructure. This is the case in San Diego, California, where the Rose Canyon fault zone trends through the highly developed downtown.
Due to regulations on development in areas of active faulting, hundreds of individual, city block-sized fault investigations have been conducted by geotechnical consulting firms in downtown San Diego since the late 1970s. The reports produced from these investigations include information on geology and faulting beneath the urban landscape that is valuable to government agencies, the geotechnical community, and earthquake scientists.
Luke Weidman, Jillian M. Maloney, and Thomas K. Rockwell compiled data from 268 of these individual reports to create the first centralized geodatabase for study of the Rose Canyon fault zone through downtown San Diego. The geodatabase includes 2020 georeferenced datapoints with links to the original data logs. The team then used the interactive geodatabase to examine the geometry of the Rose Canyon fault zone beneath the city.
Read more at: Geological Society of America
Map of the Rose Canyon fault zone (RCFZ) through San Diego (SD), California (USA) and across the San Diego Bay pull-apart basin. Grid shows population count per grid cell (~1 km2) (source: LandScan 2017, Oak Ridge National Laboratory, UT-Battelle LLC, https://landscan.ornl.gov/). DF--Descanso fault; SBF--Spanish Bight fault; CF--Coronado fault; SSF--Silver Strand fault; LNFZ--La Nacion fault zone. (Photo Credit: LandScan 2017, Oak Ridge National Laboratory, UT-Battelle LLC, https://landscan.ornl.gov/)