"Over a century of building along the Hawaiian shoreline, without this sort of detailed knowledge about shoreline change, has led to some development that is located too close to the ocean," said Dr. Charles Fletcher, UH Geology and Geophysics Professor and lead author.  "A better understanding of historical shoreline change and human responses to erosion may improve our ability to avoid erosion hazards in the future."

The researchers used historical data sources such as maps and aerial photographs to measure shoreline change at more than 12,000 locations.

Shoreline changes are measured in specialized Geographic Information System software.

This analysis of past and present trends of shoreline movement is designed to allow for future repeatable analyses of shoreline movement, coastal erosion, and land loss.

"The results of this research provide critical coastal change information that can be used to inform a wide variety of coastal management decisions," said Dr. Rob Thieler, sponsor of the study with the USGS.

The research was also supported by grants from a number of federal, state, and county agencies as well as non-profit organizations.

The report, titled "National Assessment of Shoreline Change: Historical Shoreline Change in the Hawaiian Islands," is the sixth report produced as part of the USGS’s National Assessment of Shoreline Change project, which already includes the U.S. Gulf of Mexico and Atlantic coasts, as well as California.

An accompanying report that provides the GIS data used to conduct the Hawaii coastal change analysis is being released simultaneously.