Images

In Leupueng, Indonesia, on the island of Sumatra, Dr. Guy Gelfenbaum measures the height of snapped-off tree trunks and sea level changes shortly after the December 26, 2004 earthquake and tsunami in the Indian Ocean.

As part of an international tsunami survey team, Andy Moore of Kent State University takes measurement of a snapped-off tree trunk in Leupueng, Aceh in 2005, shortly after the deadly tsunami struck the island of Sumatra.

A severely damaged home, or a portion of one, sits atop debris in Banda Aceh on the island of Sumatra. Damage was caused by a massive, highly destructive tsunami, triggered by a magnitude 9.1 earthquake just offshore of Sumatra, on December 26, 2004.

Boat carried inland by tsunami that struck Sumatra on December 26, 2004.

Photo taken about 100 meters inland at Kalmunai on Sri Lanka's east coast.

Tsunami sand deposit at Nilaveli Beach on the northeastern coast of Sri Lanka following the December 26th, 2004 earthquake and tsunami in the Indian Ocean. The sand deposited by the tsunami is light colored and overlies a pre-tsunami darker sandy soil.

Large-scale poster describing USGS work.

The USGS studied air photos of the Big Sur coast taken in 1942 and 1994, in cooperation with the California Department of Transportation (Caltrans) and the University of California at Santa Cruz (UCSC).

Diagram of deep-seated landslide, from USGS Fact Sheet 3004–3072, “Landslide Types and Processes.”

Large-scale poster describing USGS work.

Large-scale poster describing USGS work.

The USGS, in cooperation with Moss Landing Marine Laboratory, mapped the slopes of the Santa Barbara Channel using sonar. We combined this with deep sea drilling records and seismic records to make these maps.

The USGS lidar unit scanning a road embankment failure on Route 252, west of Horinouchi-Cho, in Niigata-ken, Japan. The system can be easily transported by vehicle or backpack to study sites, and travels as checked baggage.

The Great Barrier Reef arches over 2000 kilometers along the northeast coast of Australia. The white calcium carbonate that coats the coral reflects light, making the water above the reef appear bright blue from space.

Sonar-generated image showing underwater topography and the potential for landslides near the head of Resurrection Bay, Alaska. The terrain looks three times as steep as it occurs naturally. The arrow points to underwater landslide debris from the collapse of a fan-delta following the great Alaskan earthquake of 1964.

Large-scale poster describing USGS work.

The preferred method of SASW testing uses a continuous harmonic-wave source produced by a low-frequency computer-controlled electromechanical shaker (device at right) and multi-sensor linear seismometer arrays (2-sensors on the left). This site is 600-PS11, at Trans Alaska Pipeline, Alyeska Pump Station 11, Glennallen, Alaska.

Map showing the paths that ocean current-following surface drifters deployed in coral larval slicks off west Maui traveled in 24 hours following their release during a coral spawning event. Such data suggests that the coral reefs off west-central Maui may provide coral larvae to the reefs off northeastern Lānaʻi.

Underwater photograph of larvae being released into the water column from reef-building coral spawning off Maui the night of June 30, 2003. The white larvae are about 0.5 to 1.5 mm across.

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.

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.

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.