Survey explores underwater battlefield in western Pacific

The survey, conducted by a team of scientists from the US National Park Service, is the first of a two-part project.

A major survey has explored the underwater archaeology of the island of Guam, which was fought over by the Japanese and Americans during World War II.

The island in the Western Pacific, which is today an overseas territory of the United States, was captured by Japanese imperial forces in 1941. It was later liberated by the US after an invasion and battle in July 1944.

lefT A member of the dive team exploring an amtrac (amphibious tractor), one of the few known underwater relics from the 1944 US invasion of Guam. The island was occupied by the Japanese for two and a half years.
A member of the dive team exploring an amtrac (amphibious tractor), one of the few known underwater relics from the 1944 US invasion of Guam. The island was occupied by the Japanese for two and a half years. Image: National Park Service

The survey, conducted by a team of scientists from the US National Park Service, is the first of a two-part project. According to the service, the objective is to categorise submerged material relating to the 1944 invasion of the island and to study how the war affected the ecosystem of the surrounding coral reef.

On 8 December 1941, just hours after the attack on Pearl Harbor, Guam – a US territory since 1899 – was captured by troops of the Japanese Empire. The following two and a half years of occupation saw the native population subjected to forced labour, torture, and summary executions.

In July 1944, as part of Operation Forager, US troops captured Guam, along with neighbouring Mariana islands Saipan and Tinian around the same time.

Airfields were later constructed on Saipan and Tinian, from which strategic bombing missions against the Japanese home islands were launched.

During the survey, conducted in January and February this year, the team identified a clear line of blast craters inside the barrier reef of Asan beach, one of the two on which US troops landed.

The craters, the team say, correspond with the position of Japanese obstacles destroyed by American underwater demolition teams during fighting.

Other evidence of blasting includes a 200ft area of the barrier reef at Agat beach that enabled tank landing ships to offload cargo.

Additionally, the team found more than 280 ‘targets’ that they say ‘warrant further investigation’. During the second part of the survey, due to take place this summer, divers will explore each of these sites individually.

‘This project is meaningful because there has never been a comprehensive underwater inventory of the battle-related items that may still exist,’ the survey team said in a statement.

‘Evidence suggests there is a significant amount of cultural resources on the seafloor near the landing beaches of Asan and Agat.’