Volcano Watch: Aerial photographs and volcanic ash — looking back to move forward

  • Left: Aerial photograph of the Pahala area, on the southern side of the Island of Hawaii, taken on December 11, 1976. Right: The backside of the same photo showing labeled field locations, marked with a pinhole through the photograph, which correspond to the geologist’s field notes. (USGS/Special to West Hawaii Today)

A new project at the USGS Hawaiian Volcano Observatory (HVO) is once again making use of old aerial photographs and field notes that were used to make geologic and hazard maps. Buried within hundreds of old mapping photos and field notes are the locations and thicknesses of several ash deposits on the flanks of Mauna Loa that have never been fully quantified.