Search underway for key WWII battlefield hidden on Pacific seafloor off Guam, team says

A World War II battlefield frozen in time is hidden off the island of Guam, and a team of researchers has set out to find it and document what remains after 79 years on the Pacific Ocean floor.

This includes “submerged shipwrecks, aircraft, amphibious vehicles, artillery and other artifacts” that were lost, scuttled or accidentally dropped during the 1944 U.S. invasion” of the island, according to the National Park Service.

“There has never been a comprehensive underwater inventory of the battle-related items that may still exist. Evidence suggests there is a significant amount of what are now viewed as cultural resources on the seafloor near the landing beaches of Asan and Agat,” NPS investigators say.

“The team will ... map the seafloor and portions of the barrier reef near these landing beaches. They will use these data to identify the location of battle-related cultural resources and characterize the seafloor environment.”

The project, which is funded by NOAA Ocean Exploration, will last through Feb. 25 and extend from shore into waters about 200 feet deep. A second phase will involve exploring significant discoveries in the summer, officials said.

The Asan and Agat landing sites are protected as part of War in the Pacific National Historical Park, about 3,900 miles west of Hawaii. The park commemorates the American seizure of Guam and the Mariana Islands that “hastened the end of the war, but came at a price of thousands of casualties.”

Historians say the expedition is an overdue first attempt to locate artifacts that may be deteriorating more rapidly due to warming ocean temperatures.

“The results of this project will greatly expand our nation’s knowledge and our ability to tell the story of one of the most significant invasions of the Pacific Theater and a turning point in World War II — both from historical and ecological perspectives,” according to Marine Ecologist Monique LaFrance Bartley, of the NPS Ocean and Coastal Resources Branch’s Water Resources Division.

Marines plant the American flag on Guam, July 21, 1944.Photo By:Marine Corps photo
Marines plant the American flag on Guam, July 21, 1944.Photo By:Marine Corps photo

What happened on Guam

What happened on Guam is not among the best known chapters of WWII.

Shortly after the Dec. 7, 1941, attack on Pearl Harbor, the Japanese invaded Guam and seized a small number of American forces “who were unprepared for the attack,” historians say.

The island remained under Japanese control until 1944, with the Chamorro people of Guam bearing the brunt of the hardships, historians say.

“The United States didn’t have time to sufficiently mobilize its fleet and resources, as the island fell (in) just a week,” according to the U.S. Department of Defense.

“The U.S. was much more prepared by the time of the second battle, which took place July 21 to Aug. 10, 1944. ... Around 59,000 U.S. service members and a large number of native Chamorros faced about 18,000 Japanese. Fighting in the thick jungle and steep terrain was difficult for both sides, with about 3,000 U.S. troops killed and more than 18,000 Japanese dead when it was over.”

Even after the U.S. victory, an estimated “7,500 Japanese soldiers remained in the jungle,” including one soldier not discovered until Jan. 24, 1972, the department reports.

The expedition expects to find all manner of craft associated with the U.S. effort to retake the island, along with evidence of the Japanese defense and the Chamorro resistance effort.

Researchers will also document any impact the landings had on marine ecology. If area reefs suffered long-term damage, Guam is more vulnerable to storms and sea-level rise, experts say.

“We are hoping to identify the locations of the obstacles that the Japanese placed in nearshore waters, that the U.S. Underwater Demolition Teams subsequently destroyed (i.e. detonated with explosives),” Bartley says.

“Interestingly, the level of difficulty we have finding the locations of the obstacles could speak to how much the reef has recovered from the blasting over time.”

An enemy dugout is blown up near the Northern Assault Beaches of Guam in July 1944.
An enemy dugout is blown up near the Northern Assault Beaches of Guam in July 1944.

Artifacts in shallow water

The National Park Service reports “a significant amount of war material” remains out in the open in public spaces all over Pacific Islands.

This includes artifacts seen lying around the War in the Pacific National Historical Park, and the expedition intends to document those items, too.

“Members of the project team have seen evidence of material likely from World War II on shore and in shallow areas near invasion beaches across the Pacific, including in Guam,” according to project investigator Annie Wright of the NPS Submerged Resources Center.

“While the bulk of remaining artifacts and archaeological sites that we identify during this project will likely be in deeper waters, it is possible that we will find some war material visible on or near the shoreline, or in extremely shallow water accessible by wading or snorkeling.”

Among the tools being used is a magnetometer to locate objects covered by sand on the seafloor, and photogrammetry to create “very high resolution 3D models” of the sunken artifacts.

Both are needed, as concerns grow WWII artifacts in the ocean are deteriorating at a rapid pace due to rising ocean temperatures.

“World War II heritage is very much at risk from this as many World War II artifacts are made almost exclusively from metal,” Wright says.

“This project will be documenting any artifacts we find and reconstructing the battlescape. We are not recovering any artifacts or disturbing the seafloor. ... Documenting the area in its entirety is critical to preserving history and learning what we can before these artifacts are gone and it is too late.”

The project is a collaboration within National Park Service of the NPS Submerged Resources Center and the NPS Coastal and Ocean Resources Branch.

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