Images

Enlarged from previous figure, this map shows a string of basins along the fault and offset of the south wall of the Yakobi Sea Valley. Line A–B marks the location of multichannel seismic-reflection profile.

Multichannel seismic-reflection profile showing sediment layers beneath the seafloor disrupted by the Queen Charlotte-Fairweather fault near Cross Sound. The profile is approximately 16 kilometers across, and it extends approximately 370 meters beneath the seafloor. See related multimedia below, for the location of this profile.

Profile of newly discovered volcano-like cone in sonar record collected off southern Alaska. The cone’s summit is at about 1,000 meters water depth. Note fluid plume (blue) rising more than 700 meters upward from the summit.

Seafloor trace of the Queen Charlotte-Fairweather fault (from top left to bottom right) offsets the edge of the Yakobi Sea Valley off southeast Alaska. This 700-mile-long fault has generated large earthquakes in the past. Future shocks—and tsunamis—could threaten coastal communities in the U.S. and Canada. (Color-coded depths, in meters, were mapped in 2015.)

Enlarged map of the Yakobi Sea Valley. Closeup view (upper right) shows right-lateral offset of the Yakobi Sea Valley wall by the Queen Charlotte-Fairweather fault. MCS, multichannel seismic; km, kilometers. For location, see the southeastern Alaska trackline map.

This USGS vessel acquires single-beam bathymetry in shallow nearshore environments. We acquire repeat bathymetry surveys over multiple years and compute changes in bathymetry, thus allowing us to identify hotspots of erosion and deposition on short timescales.

Map showing the change in modern sediment thickness in meters between 1996-1997 and 2011 offshore of Fire Island. Green areas indicate accretion and red a

USGS pilot Sandy Brosnahan and Senate Pro Tempore Marc Pacheco discuss the use of Umanned Aerial Systems (UASs, also known as drones) to collect data in coastal environments. Photo credit: Dann Blackwood, USGS.

Bathymetry and backscatter intensity of the sea floor of the Hudson Shelf Valley location map

Map showing the tracklines and grab sample sites of the 2014 and 2015 geophysical surveys offshore of the Delmarva Peninsula.

Storm induced erosion of marsh shorelines can provide significant quantities of sediment to the bay altering the deposition patterns.

Woods Hole Coastal and Marine Science Center personnel process data in the dry lab on the M/V Scarlett Isabella

Flood tidal shoal at Barnegat Inlet, New Jersey (courtesy USGS EROS NAIP orthophotography)

Inundated marsh at Forsythe National Wildlife Refuge, New Jersey.

Box-cores provide a relatively undistributed look into the recent past to help better understand the processes contributing to sediment deposition and erosion.

Deck shot of M/V Scarlett Isabella

Surface sediments will be analyzed for various physical parameters that will be used as initial conditions in hydrodynamic and sediment transport models.

Sunset on the Delmarva Peninsula

Vector Shorelines and Associated Shoreline Change Data for the Southeast Atlantic Coast

Relative seagrass biomass in West Falmouth Harbor, MA, under current and potential future nitrogen loading scenarios. Seagrass biomass increases in western (seaward) portions of the harbor while eastern (landward) areas see new colonization by seagrass.

Measuring seagrass biomass in Chincoteague Bay, Maryland to constrain numerical models.