Images

Underwater image of Valonia fastigiata algae growing on a reef in the National Park of American Samoa on Ofu.

Aerial image of a reef flat on Ofu, American Samoa, from a thermal drone that captures both regular images and radiometric images.

USGS and NPS scientists collecting a coral core within the National Park of American Samoa on Ofu.

Graph showing corrected thermal camera imagery from the National Park of American Samoa on Ofu.

Scientists installing a wind and rain gauge in the National Park of American Samoa on Ofu.

Map of Ofu, American Samoa, showing study sites to investigate outbreaks of Valonia fastigiata algae.

Thermal camera tower method. 1) Original oblique view data 2) Orthorectified nadir view 3) thermal corrections for angular and distance dependence 4) Calibrated thermal image. 

Diagram showing oceanographic and hydrogeologic processes including submarine groundwater discharge on Ofu, American Samoa.

Chart showing relative flood risk per county as a function of sea level rise, from the study Tropical or extratropical cyclones: what drives the compound flood hazard, impact, and risk for the United States Southeast Atlantic coast? 

Graphic showing geographic location of four benchmarking sites used in the study Benchmarking satellite-derived shoreline mapping algorithms.

Study region with GTSM-ERA5 output locations marked as black circles and tide gauge locations marked as blue squares. Gray labels denote NOAA designated tide gauge station IDs. Information on tide gauges, including ID number, latitude, longitude, and the date when observations start, are listed in the table to the right of the map.

Component contributions to extreme water levels. Panel (a) shows GTSM-ERA5 stations (in black) with highlighted “multi-POT” node locations marked in red and numbered to correspond with panel (c).

Map of highest storm-driven flood impact category in 63 Alaska coastal communities for flood events from 1887 to 2022, from the study Current and projected flood exposure for Alaska coastal communities.

Cover image for the geonarrative "Paleoclimate: Lessons from the past, roadmap for the future". In this interactive geonarrative, viewers can explore the different applications of USGS paleoclimate research.

Map showing location of radar network for the Advanced Quantitative Precipitation Information system in the San Francisco Bay Area.

Animation of a computed tomography scan of a coral core.

Map of the study area from the United States-Canada border to the Bering Strait, Alaska. Simulations were carried out in stationary mode for 2,500 sea states over eight two-dimensional (2D) curvilinear and one 2D rectangular domains for a total of nine domains. The offshore extent was roughly defined by the 20-meter isobath.

Scan of coral core, showing yearly growth rates and the density of the coral, which can in turn be used to determine the calcification, or constructive process responsible for reef growth. 

Animation of a computed tomography scan of a coral core.

The newly developed USGS Coral Core Archive, housed at the Santa Cruz and St. Petersburg Coastal and Marine Science Centers, contains approximately 500 coral reef cores from U.S. jurisdictions worldwide.

Photo of coral carbonate standards, arranged from high to low density. To convert CT values to real-world densities and quantify the uncertainty in reconstructed density as a result of offsets, a set of carbonate standards are included in every CT scan that represent a range of coral species with different densities.