Locating War Beneath the Waves: Archival-Guided Multidisciplinary Documentation of World War II Blast Features in Guam

The National Park Service conducted an amphibious battlefield survey in 2023 of the Agat and Asan Beach Units of War in the Pacific National Historical Park, Guam. This exploratory project used a multidisciplinary approach to further understanding of the 1944 Battle of Guam, one of the most significant invasions of the Pacific Theater during World War II. As part of the project, the team located and documented blast features created by U.S. Navy Underwater Demolition Teams during the removal of obstacles placed on and near the landing beaches by the Japanese as deterrents. The discovery of these blast features was guided by archival research and documented through photogrammetry, bathymetry, and RTK GNSS surveys. The blast features represent intentional modification to the seafloor and were examined in archaeological and ecological contexts. This article discusses the discovery and documentation of the blast features, the long-lasting impact of World War II on the island, the value of integrating cultural and natural resource studies, and implications for maritime heritage research and management. This article concludes with considerations for future directions for archaeological and multidisciplinary research focused on seafloor modification.