Geophysical mapping and research have demonstrated that the seabed on the inner continental shelf has a variety of shapes which are linked to long-term evolution of the barrier island. Regional-scale modeling forecasts how atmospheric forcing and oceanographic circulation case sand, gravel, and other materials to be transported by tides, winds, waves, fresh water fluxes, and density variations.
The inner shelf adjacent to Fire Island is where geologic and oceanographic processes interact to influence the long-term behavior of the island and shoreline. First, mapping the geology of the inner shelf allows us to identify the sources of sediment that have contributed to the formation of Fire Island over the last several thousand years. Next, studying patterns of sediment distribution influence how much sand is transported along and across the shelf during stormy and fair-weather periods, contributing to our understanding of the historical behavior of the island. Finally, changes in inner shelf shape and slo pe alter waves as they approach the coast which can lead to spatial variability in coastal response to storms. All of this information helps coastal managers understand the sediment budget of the island so they can make sound sediment management decisions.
Coastal Change Processes
The USGS has been actively studying sediment distribution, morphology, and sub-seafloor structure of the inner shelf off of Fire Island for more than 20 years. As instrumentation has improved and as data resolution has increased, we have been able to build upon previous work to augment and refine our understanding of the geological processes that shaped the coastal landscape in the past and will continue to influence coastal behavior in the future.
Tides, winds, and waves drive currents offshore that erode and deposit sediment and change offshore morphology. Using a combination of oceanographic observations and modeling, the USGS is quantifying the processes that drive the connections between shelf geology and modern coastal behavior.
Below are other science projects associated with this project.
Coastal System Change at Fire Island, New York
Back-barrier and Estuarine - Coastal System Change at Fire Island, New York
Oceanside Beaches and Dunes - Coastal System Change at Fire Island, New York
Nearshore - Coastal System Change at Fire Island, New York
Coastal Change Processes- Fire Island, NY
Below are data or web applications associated with this project.
High-resolution geophysical data collected offshore of Fire Island, New York in 2011, U.S. Geological Survey Field Activity 2011-005-FA
Below are publications associated with this project.
Change in morphology and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York between 2011 and 2014: Analysis of hurricane impact
Assessing the impact of Hurricanes Irene and Sandy on the morphology and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York
Maps showing bathymetry and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York, pre-Hurricane Sandy
Modification of the Quaternary stratigraphic framework of the inner-continental shelf by Holocene marine transgression: An example offshore of Fire Island, New York
Geologic evidence for onshore sediment transport from the inner continental shelf: Fire Island, New York
Improving understanding of near-term barrier island evolution through multi-decadal assessment of morphologic change
- Overview
Geophysical mapping and research have demonstrated that the seabed on the inner continental shelf has a variety of shapes which are linked to long-term evolution of the barrier island. Regional-scale modeling forecasts how atmospheric forcing and oceanographic circulation case sand, gravel, and other materials to be transported by tides, winds, waves, fresh water fluxes, and density variations.
The inner shelf adjacent to Fire Island is where geologic and oceanographic processes interact to influence the long-term behavior of the island and shoreline. First, mapping the geology of the inner shelf allows us to identify the sources of sediment that have contributed to the formation of Fire Island over the last several thousand years. Next, studying patterns of sediment distribution influence how much sand is transported along and across the shelf during stormy and fair-weather periods, contributing to our understanding of the historical behavior of the island. Finally, changes in inner shelf shape and slo pe alter waves as they approach the coast which can lead to spatial variability in coastal response to storms. All of this information helps coastal managers understand the sediment budget of the island so they can make sound sediment management decisions.
Coastal Change Processes
The USGS has been actively studying sediment distribution, morphology, and sub-seafloor structure of the inner shelf off of Fire Island for more than 20 years. As instrumentation has improved and as data resolution has increased, we have been able to build upon previous work to augment and refine our understanding of the geological processes that shaped the coastal landscape in the past and will continue to influence coastal behavior in the future.
Tides, winds, and waves drive currents offshore that erode and deposit sediment and change offshore morphology. Using a combination of oceanographic observations and modeling, the USGS is quantifying the processes that drive the connections between shelf geology and modern coastal behavior.
- Science
Below are other science projects associated with this project.
Coastal System Change at Fire Island, New York
Fire Island is a 50-km long barrier island along the south shore of Long Island, New York. The island is comprised of seventeen year-round communities; federal, state, and county parks; and supports distinct ecosystems alongside areas of economic and cultural value. In addition to providing resources to its residents, the barrier island also protects the heavily-populated mainland from storm waves...Back-barrier and Estuarine - Coastal System Change at Fire Island, New York
Regional-scale modeling forecasts how atmospheric forcing and oceanographic circulation influence estuarine circulation and water levels, sediment transport, and wetland change.Oceanside Beaches and Dunes - Coastal System Change at Fire Island, New York
Oceanfront research at Fire Island, New York, is primarily focused on understanding the long- and short-term behavior of the ocean-facing terrestrial barrier island system, including human influences. The USGS has had ongoing research activities on Fire Island since the late 1990s, providing science to help inform management decisions. Recent efforts include monitoring the response to and recovery...Nearshore - Coastal System Change at Fire Island, New York
The nearshore is the submerged portion of the shoreface between the inner shelf and the shoreline and includes the surf zone, where waves break. Along with beaches and dunes, nearshore morphology and geology adjusts to changes in waves, sediment supply, human alterations, and sea level rise. By measuring nearshore morphologic and geologic variations, we can understand how quickly beaches and dunes...Coastal Change Processes- Fire Island, NY
Fire Island, a 50-km long barrier-island system between Fire Island Inlet and Moriches Inlet, attracts significant tourism, includes federal, state, and county parks, contains a number of coastal communities, provides storm damage protection to the adjacent heavily populated mainland, and supports a distinct barrier island ecosystem, all of which are affected by coastal change. Mitigating the... - Data
Below are data or web applications associated with this project.
High-resolution geophysical data collected offshore of Fire Island, New York in 2011, U.S. Geological Survey Field Activity 2011-005-FA
The U.S. Geological Survey (USGS) mapped approximately 336 square kilometers of the lower shoreface and inner-continental shelf offshore of Fire Island, New York in 2011 using interferometric sonar and high-resolution chirp seismic-reflection systems. These spatial data support research on the Quaternary evolution of the Fire Island coastal system and provide baseline information for research on c - Publications
Below are publications associated with this project.
Change in morphology and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York between 2011 and 2014: Analysis of hurricane impact
Seafloor mapping investigations conducted on the lower shoreface and inner continental shelf offshore of Fire Island, New York in 2011 and 2014, the period encompassing the impacts of Hurricanes Irene and Sandy, provide an unprecedented perspective regarding regional inner continental shelf sediment dynamics during large storm events. Analyses of these studies demonstrate that storm-induced eroAssessing the impact of Hurricanes Irene and Sandy on the morphology and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York
This report documents the changes in seabed morphology and modern sediment thickness detected on the inner continental shelf offshore of Fire Island, New York, before and after Hurricanes Irene and Sandy made landfall. Comparison of acoustic backscatter imagery, seismic-reflection profiles, and bathymetry collected in 2011 and in 2014 show that sedimentary structures and depositional patterns moveMaps showing bathymetry and modern sediment thickness on the inner continental shelf offshore of Fire Island, New York, pre-Hurricane Sandy
The U.S. Geological Survey mapped approximately 336 square kilometers of the lower shoreface and inner continental shelf offshore of Fire Island, New York, in 2011 by using interferometric sonar and high-resolution chirp seismic-reflection systems. This report presents maps of bathymetry, acoustic backscatter, the coastal plain unconformity, the Holocene marine transgressive surface, and modern seModification of the Quaternary stratigraphic framework of the inner-continental shelf by Holocene marine transgression: An example offshore of Fire Island, New York
The inner-continental shelf off Fire Island, New York was mapped in 2011 using interferometric sonar and high-resolution chirp seismic-reflection systems. The area mapped is approximately 50 km long by 8 km wide, extending from Moriches Inlet to Fire Island Inlet in water depths ranging from 8 to 32 m. The morphology of this inner-continental shelf region and modern sediment distribution patternsGeologic evidence for onshore sediment transport from the inner continental shelf: Fire Island, New York
Sediment budget analyses along the south shore of Fire Island, New York, have been conducted and debated in the scientific and coastal engineering literature for decades. It is well documented that a primary component of sediment transport in this system is directed alongshore from E to W, but discrepancies in volumetric sediment budget calculations remain. An additional quantity of sand, averaginImproving understanding of near-term barrier island evolution through multi-decadal assessment of morphologic change
Observed morphodynamic changes over multiple decades were coupled with storm-driven run-up characteristics at Fire Island, New York, to explore the influence of wave processes relative to the impacts of other coastal change drivers on the near-term evolution of the barrier island. Historical topography was generated from digital stereo-photogrammetry and compared with more recent lidar surveys to