A tidal marsh bank exposed during low tide on Sitkinak Island, Alaska. The bank reveals ledges of alternating peat and silt. Abrupt uplift and subsidence during large megathrust earthquakes is interpreted to be the cause of the alternating layers.
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Geologic Studies on Sitkinak Island, Alaska
A tidal marsh bank exposed during low tide on Sitkinak Island, Alaska. The bank reveals ledges of alternating peat and silt. Abrupt uplift and subsidence during large megathrust earthquakes is interpreted to be the cause of the alternating layers.
Geologic Studies on Sitkinak Island, Alaska
Base camp, Sitkinak Island.
Base camp, Sitkinak Island.
Geologic Studies on Sitkinak Island, Alaska
Geologists examine cores on Sitkinak Island, Alaska.
Geologists examine cores on Sitkinak Island, Alaska.
Geologic Studies on Sitkinak Island, Alaska
Geologists examine an exposure of a tidal marsh bank on Sitkinak Island, Alaska. The bank exposes interbedded peat and silt that records sudden vertical land movements associated with megathrust fault slip during large earthquakes.
Geologists examine an exposure of a tidal marsh bank on Sitkinak Island, Alaska. The bank exposes interbedded peat and silt that records sudden vertical land movements associated with megathrust fault slip during large earthquakes.
Geologic Studies on Sitkinak Island, Alaska
Geologists extract a hand-driven core from 2-3 m depth on Sitkinak Island, Alaska. The cores contain peat with interbedded sand layers that record inundation of the coast by prehistoric tsunamis. (l-r: Peter Haeussler, USGS; Andrew Kemp, Tufts University; Alan Nelson, USGS)
Geologists extract a hand-driven core from 2-3 m depth on Sitkinak Island, Alaska. The cores contain peat with interbedded sand layers that record inundation of the coast by prehistoric tsunamis. (l-r: Peter Haeussler, USGS; Andrew Kemp, Tufts University; Alan Nelson, USGS)
Geologic Studies on Sitkinak Island, Alaska
Geologists driving a core into marsh sediment to document interbedded peat and silt that records sudden vertical land movements associated with megathrust fault slip during large earthquakes.
Geologists driving a core into marsh sediment to document interbedded peat and silt that records sudden vertical land movements associated with megathrust fault slip during large earthquakes.
Rainbow Over Yukon River, Eagle, Alaska, June 2002
Eagle was our put-in point for our first synoptic cruise down the Yukon River.
Eagle was our put-in point for our first synoptic cruise down the Yukon River.
Repeat oblique photographs of Gulkana glaciers in Alaska.
Repeat oblique photographs of Gulkana glaciers in Alaska. 1967, Unknown USGS photographer. 2016, L. Sass, USGS.
Repeat oblique photographs of Gulkana glaciers in Alaska. 1967, Unknown USGS photographer. 2016, L. Sass, USGS.
Repeat oblique photographs of Wolverine glacier in Alaska.
Repeat oblique photographs of Wolverine glacier in Alaska. 1966 image by unknown USGS photographer; 2015 image by L. Sass, USGS.
Repeat oblique photographs of Wolverine glacier in Alaska. 1966 image by unknown USGS photographer; 2015 image by L. Sass, USGS.
Chenega Village after tsunami waves hit in 1964
Photograph taken in 1964 of the main part of the Chenega village site in Alaska. Pilings in the ground mark the former locations of homes swept away by tsunami waves. The schoolhouse on high ground was undamaged.
Photograph taken in 1964 of the main part of the Chenega village site in Alaska. Pilings in the ground mark the former locations of homes swept away by tsunami waves. The schoolhouse on high ground was undamaged.
Muir and Riggs Glaciers, Muir Inlet, Alaska - 1950
This, the first of two repeat photographs, documents significant changes that have occurred during the nine years between photographs A and B. Although Muir Glacier has retreated more than 3 kilometers and thinned more than 100 meters, exposing Muir Inlet, it remains connected with tributary Riggs Glacier. White Thunder Ridge remains devoid of vegetation.
This, the first of two repeat photographs, documents significant changes that have occurred during the nine years between photographs A and B. Although Muir Glacier has retreated more than 3 kilometers and thinned more than 100 meters, exposing Muir Inlet, it remains connected with tributary Riggs Glacier. White Thunder Ridge remains devoid of vegetation.
Muir and Riggs Glaciers, Muir Inlet, Alaska - 1941
This northeast-looking photograph, on the southeastern side of White Thunder Ridge ,shows the lower reaches of Muir Glacier, then a large tidewater calving valley glacier, and its tributary Riggs Glacier. The séracs in the lower right-hand corner of the photograph mark Muir Glacier’s terminus. The ice thickness is more than 700 meters.
This northeast-looking photograph, on the southeastern side of White Thunder Ridge ,shows the lower reaches of Muir Glacier, then a large tidewater calving valley glacier, and its tributary Riggs Glacier. The séracs in the lower right-hand corner of the photograph mark Muir Glacier’s terminus. The ice thickness is more than 700 meters.
Katmai National Park and Preserve, Alaska
Volcanic ash drifts around houses at Katmai after the June 1912 eruption of Novarupta Volcano. Church in the distant background. August 13, 1912.
Volcanic ash drifts around houses at Katmai after the June 1912 eruption of Novarupta Volcano. Church in the distant background. August 13, 1912.