Images

Coral atolls develop from reefs fringing volcanic islands. As first hypothesized by Charles Darwin, and confirmed by ocean drilling done by British scientists a century ago, reefs fringing volcanic islands build vertically to sea level, forming steep-walled barrier reefs.

Many coral reefs fringing coasts consist of nearshore inner reef flats that slope to deeper water fore reefs farther offshore. The reef crest, between the inner reef flat and outer fore reef, lies in extremely shallow water and may be exposed during the lowest tides. Waves commonly crash against or break on the reef crest.

Overall perspective view of the Los Angeles Margin and Basin looking northeast. The distance across the bottom of the image is about 100 kilometers with a vertical exaggeration of 6 times. The margin is bisected by a series of large underwater canyons, channels, and gullies.

Photograph of a coastal cliff where a large landslide occurred between 2002 and 2010. This photo, taken in 2002, shows the cliff before the landslide.

Large-scale poster describing USGS work.

The USGS mapped Crater Lake, Oregon using sonar, in cooperation with the National Park Service, the University of New Hampshire, and C&C Technologies.

A bed of manganese nodules from deep offshore of the Cook Islands; photo sourced from Hein et al., 2015, taken during a Japanese research cruise in the year 2000. Nodules range from about 2 to 10 centimeters across.

A bed of manganese nodules from deep offshore of the Cook Islands. Each color bar in the staff represents 10 centimeters.

This image was acquired on December 26, 2000, by the Enhanced Thematic Mapper plus instrument aboard NASA’s Landsat 7 satellite.

The south area of the La Honda oil field, California, was discovered during the late 1950s and produced an estimated 595,000 barrels of oil from about 12 wells, including the well in this photo.

An earthquake along a subduction zone happens when the leading edge of the overriding plate breaks free and springs seaward, raising the sea floor and the water above it. This uplift starts a tsunami. Meanwhile, the bulge behind the leading edge collapses, thinning the plate and lowering coastal areas.

Large-scale poster describing USGS work.

The USGS mapped western San Francisco Bay using sonar, in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and C&C Technologies. Some parts of the Bay floor are so shallow that a large tanker or container ship could run aground at low tide and create a massive oil spill.

George Tate (right, in light baseball cap) drives a raft on the Colorado River in Grand Canyon, 1992. The crane near the bow was used to deploy a small tripod holding a rotating sidescan sonar, which sat on the riverbed recording the motion of underwater sand dunes.

Extensive coral reefs are found in the waters of the United States and its territories. In the Atlantic Ocean, Gulf of America, and the Caribbean Sea these include reefs off Florida, Texas, Puerto Rico, and the U.S. Virgin Islands.

An automobile lies crushed under the third story of this apartment building in the Marina District. The ground levels are no longer visible because of structural failure and sinking due to liquefaction.

Large-scale poster describing USGS work.

The USGS, in cooperation with the UK Institute of Oceanographic Sciences (IOS) and others, took images of the seafloor 200 miles around the Hawaiian Islands using GLORIA. GLORIA is a long-range sonar that gives a bird’s-eye view of the seafloor.

Sea Beam bathymetric map of southern Escanaba Trough study area. Contour interval is 10m and is noted by color change. Locations of single- channel water-gun reflection profiles 4 to 12, cruise L1-86-NC, are shown.

Photo shows the side of an actively venting massive sulfide chimney colonized by tube worms and palm worms.

Sea Beam bathymetric map of Escanaba Trough from 1985. A, Northern half. B, Southern half. Contour interval is 50 m; each color change represents 100 m. Yellow indicates areas of no data.

Older, oxidized sulfide deposit colonized by sponges at SESCA site, southern half of Escanaba Trough.

Sulfide mound and talus at NESCA site, northern half of Escanaba Trough. Rectangular marker at center of photograph is 15 by 30 cm.

Dynaphot photomicrographs of foraminifers from Escanaba Trough. A-D, Rhabdammina sp.