Conference Agenda

This paper discusses the results of an archaeological survey of Bundschu Ridge in the Asan Unit of War in the Pacific National Historical Park, Guam, which was the site of heavy fighting in the first days of the United States invasion of Guam in July, 1944, during WWII. Part of a multi-phase project in partnership with the Defense POW/MIA Accounting Agency (DPAA), this survey follows up on previous work that acquired LiDAR imagery of the area and identified potential battlefield features. A combination of pedestrian survey, metal detection, and subsurface testing was used to ground-truth the imagery and map battlefield features. This aids in improving methods for identifying WWII battlefield features in LiDAR imagery and in understanding the movement of troops in this area during the fighting in support of potential future recovery missions by the DPAA.

Dense tropical vegetation challenges World War II battlefield documentation in the Pacific Theater. We present UAV-based lidar advances developed through fieldwork at Guadalcanal, Solomon Islands, and Guam's War in the Pacific National Historical Park. While conventional airborne lidar struggles with dense canopy, UAV platforms at 50m altitude achieve ground point densities exceeding 5,000 returns per square meter. However, raw density inadequately assesses data quality where 99% of returns originate from vegetation. We introduce "effective ground feature resolution" for evaluating detection capabilities for foxholes, defensive positions, and trails. Systematic testing of flight parameters—transect spacing (10-40m), speed (3-10 m/s), and azimuth orientations—demonstrates that multiple overlapping flights significantly enhance ground penetration. Comparative analysis of sensor platforms reveals substantial performance variations. Detecting small battlefield features (0.1-0.25m resolution) requires extraordinarily high point densities and meticulous flight planning. This methodology enables documentation of previously invisible Pacific Theater battlefield landscapes.

American Marine landings on Tulagi and Guadalcanal Islands in the Solomon Islands during August 1942 were the first terrestrial battles between the U.S. and Japan during World War II. The eventual defeat of Japan on Guadalcanal began the grinding American offense on islands to the west and north and Japan’s ultimate surrender. Until recently, the pivotal Guadalcanal battlefields have not been documented as landscape-scale archaeological sites. These battlefields are important as multi-national historical resources of the Pacific Theater, case studies for the further development of archaeological methods for investigating battlefields, and, significantly for the U.S., the recovery of the remains of missing servicemembers. We present the results of UAV-mounted remote sensing, pedestrian survey and mapping, historical research, and spatial analysis for “the Gifu,” a portion of the Mount Austen area that saw fierce fighting from December 1942-January 1943.

The Pacific Theater was a testing ground for the development, refinement, and antagonism of the American amphibious assault. Covering the land-water interface, WWII landing beaches remain an integral part of the Pacific WWII battlescape. On the small island of Peleliu, the landing beaches from the 1944 amphibious assault have retained a high degree of integrity due to limited post-war resettlement. With recent military land development, however, Peleliu’s battlefield is undergoing transformative change. This presentation discusses the physical remains of war located on Peleliu’s landing beaches. It further frames these materials in broader contexts of battlefield significance and integrity that may be relevant to sites across the Pacific.

On 15 June 1944 the United States began the invasion of Saipan initiating the Battle for Saipan. The invasion was conducted as an amphibious assault on the Western shores of the island. Archaeological survey was conducted in targeted areas within the sectors of Green, Blue and Yellow Beaches during the period of 8 July 2025 to 14 July 2025 on various sites located within the amphibious landing zone. The archaeological data from the survey, previous archaeological data, and historical analysis have been utilized for a military terrain analysis, KOCOA (Key terrain, Observation and fields of fire, Cover and concealment, Obstacles, and Avenues of approach and withdrawal), to gain a better understanding of the events that unfolded in the amphibious landing zone at Saipan and how the landscape influenced these events.

Orote Peninsulaʻs strategic location and steep cliffs have made it a key defensive position on Guam since at least the 18th century. After seizing Guam in 1941, Imperial Japan built an airfield, repair and refueling stations, and antiaircraft positions on the peninsula. In 1944, U.S. forces recaptured Guam, destroying Japanese military infrastructure and undertaking a massive campaign to rebuild and expand military installations on the island as part of the Pacific Advance Basing strategy. Construction of Naval Air Station Orote was completed in 1945 and expanded through 1949 when it was decommissioned. At least 74 archaeological sites have been recorded on the peninsula; Orote Field was listed in the National Register of Historic Places in 1975. Combining archival research, archaeological survey and testing, and historic landscape analyses, this paper adds valuable new details about the U.S. airfield and presents a revised boundary for the NRHP listing.

The Defense POW/MIA Accounting Agency undertakes the critical mission of locating, identifying, and repatriating the remains of missing American personnel from past conflicts. This humanitarian effort extends to diverse and challenging environments, with underwater search and recovery operations presenting unique complexities. These operations often necessitate collaborative partnerships to leverage specialized expertise and resources. One particular challenge arises in the vicinity of former PBY Catalina bases, where undocumented practices, such as the creation of underwater parts dumping sites, can significantly impede the accurate identification of aircraft loss locations. This paper will delve into a specific case study, illustrating how a submerged debris field near a former PBY base complicated and delayed the positive identification of the intended target aircraft in the Solomon Islands.

This paper presents findings from an underwater archaeological survey of West Loch and Waipiʻo Peninsula at Joint Base Pearl Harbor-Hickam (JBPHH), Oʻahu. Using multibeam and single-beam echosounders, along with diver-led target investigations and visual surveys, we identified submerged cultural resources at four locations in the Waipiʻo area and two in West Loch. While none of the Waipiʻo sites appear eligible for the National Register of Historic Places (NRHP), two West Loch features, a possible sunken vessel and probable floating dock wreckage, may qualify under Criterion D. These may be linked to the May 1944 West Loch disaster, a little-known but significant World War II event. This research highlights the value of remote sensing and diver investigations in identifying submerged heritage. It contributes to ongoing efforts in naval base compliance, long-term cultural resource management, and public engagement with overlooked episodes of WWII maritime history in a culturally and environmentally sensitive region.

In 2024, AECOM conducted an underwater archaeological survey (remote sensing and target investigation) in Apra Harbor, Guam in support of potential future harbor development. This survey was conducted to provide Naval Facilities Engineering Systems Command (NAVFAC), Marianas with the necessary information to determine the potential effects of harbor development on historic properties. The remote sensing survey utilized a marine magnetometer, side scan sonar, and multibeam echosounder. Due to water depths ranging from 5 to 165 feet, a Seamor Chinook ROV was utilized for target investigations. A total of 20 targets were investigated including US Navy Lighterage Pontoons, an amphibious vehicle, a Japanese seaplane, and numerous anchors with chains. This paper will discuss methodological considerations when working in challenging environments with a diverse set of cultural resources and explore the identified resources and resource types within the broader context of Guam during World War II.

Although Saipan was meticulously combed, recorded, and studied by U.S. military personnel immediately following the end of the battle for the island, there is still ample room for new data to be gathered on the Japanese defenses there. During the summer of 1029, graduate students Jack “Gus” Adamson and Aleck Tan with the assistance of Saipan’s Historic Preservation Office archaeologists Jim Pruitt and Lucas Simonds conducted a pedestrian survey to ground truth the possible location of a previously unrecorded Japanese artillery position in Saipan’s western hills. Thorough background research combined with ArcGIS Pro had identified this possible position and handheld GPS and photogrammetry were used to record the data obtained in the field. The resulting dataset revealed material evidence of an artillery piece in the vicinity, but was inconclusive as to a precise location.

While Guam and the Northern Mariana Islands rapidly approach the 80^th anniversary of WWII in the Pacific, the civilian loss and tragedy of that period remains in the memory of survivors and their families and communities. Parades and speeches retell accounts of combat and suffering as do the Veterans Cemeteries, Peace Monuments, and Memorial Parks still frequented by locals and visitors on every island. Less often visited are the archaeological sites of farmsteads and lanchos with long-abandoned house foundations, kitchens, water cisterns, bathrooms, animal pens, and gardens now overgrown in the jungles, but once the homes and hopes of many CHamoru, Carolinian, Okinawan, and Japanese families. Also silent are the steep cliffs and dark caves and dense jungles where suffering and food were shared by young and old, day and night, until acts of desperation or fighting ceased.

There are approximately 8,500 shipwrecks lying across the seafloor today at risk of contaminating the local ecology – most are from World War I and World War II (Michel et al. 2005:iii). Contaminants affect life on the seafloor and the Blue Economy of communities that depend on this environment. Underwater cultural heritage (UCH) is inherent to supporting tourism and fisheries in western Pacific Island communities. Through the study of contaminant data recovered from WWII shipwrecks involved in the WWII Battle for Saipan and interviews with community and stakeholder members, this project aims to better understand how anthropogenic and ecological forces affect each other and the communities living nearby. The project will achieve this goal through a warfare ecological framework – a means of understanding and examining how three stages of war – preparations, war, and postwar activities – affect the local ecosystems and socioeconomic systems with which they interact.