Images

Twentymile bridge

Aerial photographs were collected from a small, fixed-wing aircraft over the coast of Barter Island, Alaska on July 01 2014, September 07 2014. Precise aircraft position information and structure-from-motion photogrammetric methods were combined to derive a high-resolution orthophotomosaic.

USGS scientists, working with researchers from the University of Ghent, probed the floor of Eklutna Lake, Anchorage Borough, Alaska, for evidence of turbidity currents triggered by strong shaking during the 2018 Mw7.1 Anchorage earthquake.

Landslide near Potter Hill, Anchorage, Alaska, after 2018 Anchorage earthquake.

Cores were collected from various areas of thawing permafrost-peatlands in Alaska. Permafrost thaw results in ground subsidence and inundation that kills black spruce and other understory plants living on the permafrost plateau. 

Animation of Twelvemile Lake in the Yukon Flats ecoregion in Alaska, created using USGS Landsat data.

Caption: Trees tipping over and dying as ice-rich permafrost thaws in the Innoko National Wildlife Refuge, Alaska.

Thawing permafrost on various peatlands in Alaska. Permafrost thaw results in ground subsidence and inundation that kills black spruce and other understory plants living on the permafrost plateau. The black spruce forests found on permafrost plateaus are replaced with sedge- and moss-dominated bogs and fens, altering the ecosystem structure and function.

Map of Alaska showing probability (%) of change occurrence. Insets show fire boundaries from the Bureau of Land Management (BLM) Large Fire Database and Landsat 8 imagery (bottom right; 2016) north of Fairbanks, Alaska.

A USGS scientist investigates cracks along Trunk Road in Wasilla, Alaska. Extensional crack and damage to roadway along S Trunk Rd.

A USGS scientist stands in a crack in tide flat sediment that opened during strong shaking in the November 30, 2018 Anchorage earthquake. This upland ground crack near Cottonwood Creek, Palmer Slough had horizontal displacements of ~2.5ft locally and observed maximum depth of ~3ft. The crack was observed ~150ft from the active river channel.

Exposed sand within a extensional crack along the Knik River, Alaska. Measuring a crack in sandy sediment along the south bank of the Knik River. This crack was one of many that opened across the Anchorage and Mat-Su region due to strong shaking during the M7.1 November 30, 2018 Anchorage earthquake.

Landslide from bluff below rail grade north of Rabbit Creek. Main scarp of slump/flow slide at Potter Hill. Railroad grade is to the left, tidal flat to the right. Note ponded drainage and disrupted slide material.

2018 Anchorage Earthquake

Lateral spread cracks at the north end of the Port of Anchorage, Alaska. These cracks were among many that opened across the Anchorage and Mat-Su region due to strong shaking during the M7.1 November 30, 2018 Anchorage earthquake.

Lateral spread cracks at northern end of Port of Anchorage. These cracks were among many that opened across the Anchorage and Mat-Su region due to strong shaking during the M7.1 November 30, 2018 Anchorage earthquake.

Extensional cracking and settling around private residence in Chugiak.

2018 Anchorage Earthquake

Crack observed in 2018 along headscarp of 1964 Government Hill landslide.

2018 Anchorage Earthquake

Slumping along the Alaska Railroad right-of-way evolved into long-runout landslides. The same area failed in earthquakes in 1954 and 1964.

2018 Anchorage Earthquake

Superficial slides along Eagle River east of Eagle River Loop Road. 

2018 Anchorage Earthquake

Eklutna Lake dam appeared to be undamaged the day after the earthquake; overflights of the lake showed no landslides impacted the lake shoreline.

USGS scientists conduct an aerial inspection of a line of sand vents along the Cook Inlet tide flat at Earthquake Park in Anchorage. Cook Inlet coastal plain liquefaction and bluff raveling near Earthquake Park. These vents opened and ejected sand due to liquefaction triggered by strong shaking during the M7.1 November 30, 2018 Anchorage earthquake.