UAV-based post disaster assessment of cultural heritage sites following the 2014 South Napa Earthquake

On Sunday, August 24, 2014, the American Canyon (South Napa) Earthquake occurred at 3:20am local time with moment magnitude MW of 6.1, causing damage with and estimated economic impact of over one billion dollars. Many historic landmarks were severely damaged, some too dangerous to access, while others where simply difficult or impossible to reach quickly by conventional means. This paper explores semi- automatic surveying techniques using unmanned aerial vehicles (UAVs) to support immediate post-earthquake perishable data collection and damage assessment in the context of a case study for the Trefethen Family Vineyard. This case study will examine the methods used to create 3D models through Structure from Motion, which uses photogrammetric data to recreate the geometry of the site being imaged. The ability to recreate accurate models of real world objects rapidly, using images from low cost drones underlines the increasing feasibility of using UAVs for emergency response scenarios.