Skip to main content
U.S. flag

An official website of the United States government

Two samples of beach sediment from Ichinomiya, Japan.

Detailed Description

Two samples of beach sediment from Ichinomiya, Japan. This beach was the likely source for the sand used in the balloon bombs. 

During World War II, USGS scientist Julia Gardner, at 59 years-old, served the war effort again (previously served as an auxiliary nurse during World War I) this time as a member of the Military Geology Unit. She became the leader of a group known as "The Dungeon Gang" and her expertise helped locate the Japanese military’s launch sites for balloon-borne incendiary bomb attacks against the U.S. Pacific Northwest, by analyzing seashells in the balloons’ sand ballast.  

The sand ballast inside the balloons contained seashells that originated from specific coastal regions. Gardner’s expert eyes could recognize these shells and traced their origins. By studying the types of molluscs represented in the seashells, she could pinpoint the exact locations where the balloons were launched. 


Public Domain.

Image provided courtesy of the Paleontological Research Institution, Ithaca, New York.