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Coastal Landforms and Historical Shoreline Change on the West Coast of Hawai'i
Scientists from the U.S. Geological Survey (USGS)'s Coastal and Marine Geology Program have recently begun work with the National Park Service (NPS) to help create an inventory of geologic resources for two National Historical Parks (NHPs) and one National Historic Site (NHS) on the west coast of the Big Island of Hawai'i. Part of this effort involves making coastal-landform maps to be incorporated into a geographic information system (GIS) data layer. A long-term historical shoreline change analysis is also part of the inventory.
In February 2004, a team of scientists from the USGS offices in Santa Cruz and Menlo Park, CA (Cheryl Hapke, Bruce Richmond, and Tom Reiss), conducted ground-based fieldwork at the three sites: Kaloko-Honokohau NHP, Pu'ukohola Heiau NHS, and Pu'uhonua O Honaunau NHP on Hawai'i's west coast. The purpose of the fieldwork was to collect ground-control points for photogrammetric processing of aerial photographs that will be used in the shoreline-change analysis, as well as to begin mapping coastal landforms in the parks.
The first phase of the coastal landform mapping focused on identifying shoreline features. Large segments of all three of the parks' shorelines consist of a low-lying basalt terrace or bench overlain by carbonate sand and gravel beaches. These perched, or storm, beaches are typically active only during large-wave events. As luck would have it, the team arrived for their fieldwork during just such an event; however, access to many of the beaches was closed because of hazardous conditions. Although large-wave events are positive processes in terms of delivering sediment to the beaches, these events are also responsible for damage to many of the unique Hawaiian historic sites that dot the coast. An improved understanding of the processes that shape the parks' coast will help park personnel better manage park resources. Future work will include additional offshore surveys to continue mapping of the coral reefs at Kaloko-Honokohau NHP and initiation of offshore mapping at both Pu'ukohola Heiau NHS and Pu'uhonua O Honaunau NHP. More detailed coastal landform mapping will also be conducted at all three parks.
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in this issue:
Study Notes Increased Disease in Marine Life Cape Cod Natural History Conference |