Rates and patterns of surface deformation from laser scanning following the South Napa earthquake, California

摘要: The A.D. 2014 M6.0 South Napa earthquake, despite its moderate magnitude, caused significant damage to the Valley in northern California (USA). Surface rupture occurred along several mapped and unmapped faults. Field observations following earthquake indicated that magnitude of postseismic surface slip was likely approach or exceed maximum coseismic as such presented ongoing hazard infrastructure. Using a laser scanner, we monitored deformation three dimensions through time 0.5 km main rupture. A key component this study is demonstration proper alignment repeat surveys using point cloud–based methods minimize error imposed by both local survey errors global navigation satellite system georeferencing errors. solid modeling natural cultural features, quantify dextral displacement at hundred points near fault trace. We also total initially straight features. Total from first 2.5 d ranges 0.22 0.29 m. This range increased 0.33–0.42 m 59 post-earthquake. Furthermore, estimate up 0.15 vertical during post-earthquake, which then ∼0.02 not expressed distinct step scarp trace but rather broad up-to-the-west zone increasing elevation change spanning over tens meters, challenging common notions about development strike-slip systems. Integrating these analyses provides three-dimensional mapping identifies spatial variability attribute distributed via subtle block rotation. These results indicate benefits scanner active faults demonstrate fine-scale has been missed traditional response methods.