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Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential tsunami hazards for the city of Sand Point, on Popof Island in the Shumagin Islands archipelago. We numerically modeled the extent of inundation from tsunami waves generated by local and distant earthquake sources. We considered the results in light of historical observations. The worst-case scenarios are defined by analyzing results of the sensitivity study of the tsunami dynamics with respect to different slip distributions along the Aleutian megathrust. For the Sand Point area, the worst-case scenarios are thought to be thrust earthquakes in the Shumagin Islands region with magnitudes...
This data lists the historically active volcanoes of Alaska and the year of the last major eruptive event. The volcanoes listed meet at least one of the following criteria since 1700 CE: (1) documented, unquestioned eruption, or (2) a strongly suspected eruption, often an eruption documented in the historical account with very little information (current geologic knowledge must not contradict the eruption account), or (3) persistent (usually on the order of decades, but certainly longer than several months) fumaroles, with temperatures (where measured) within ~10 degrees C of the boiling point, or (4) significant, measured, volcanic-related, non-eruptive deformation, (5) documented earthquake swarm with strongly...
The data consist of levels of organic pollutants found in the blue mussels (Mytelus trossulus) samples from 44 sites along the Aleutian archipelago and in Cross Sound in southeast Alaska. For each site, the percent lipid, percent water and the sum of the target organic compounds are reported. The compounds are PCBs (polychlorinated biphenyls), DDTs (dichlorodiphenyltrichloroethanes), HCHs (hexachlorocyclohexanes), chlordane, and HCB (hexachlorocyclobenzene).
Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
Okmok volcano, Aleutian Islands, Alaska, explosively erupted over a five-week period between July 12 and August 23, 2008. The eruption was predominantly phreatomagmatic, producing fine-grained tephra that covered most of northeastern Umnak Island. The eruption had a maximum Volcanic Explosivity Index (VEI) of 4, with eruption column heights up to 16 km during the opening phase. Several craters and a master tuff cone formed in the caldera as a result of phreatomagmatic explosions and accumulated tephra-fall and surge deposits. Ascending magma continuously interacted with an extensive shallow groundwater table in the caldera, resulting in the phreatomagmatic character of the eruption. Syneruptive explosion and collapse...
In support of geologic mapping and hazards evaluation in and near Whittier, Alaska, the Division of Geological & Geophysical Surveys (DGGS) acquired, and is making publicly available, lidar (light detection and ranging) data for an area along Passage Canal, Portage Lake, and Portage Glacier Highway. The lidar data, acquired and processed by Watershed Sciences, Inc. (WSI) consist of continuous coverage encompassing an area extending from Portage Lake eastward to Logging Company Bay in Passage Canal in the Seward D-4, D-5, and D-6 1:63,360-scale quadrangles. Lidar data collected below 1,600 ft (488 m) elevation have a minimum average pulse density of 8 pulses/square meter; above 1,600 ft (488 m) data were collected...
Potential tsunami hazard for the Umnak Island community of Nikolski is evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Aleutian megathrust. The worst-case scenarios for Nikolski are thought to be thrust earthquakes in the Umnak Island region with their greatest slip at 10-30 km (6.2-19 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture in the area of Umnak Island. The maximum predicted water depth on Main Street is about 15 m (49 ft), while the maximum current...
Between 1979 and 1982, the Alaska Division of Geological & Geophysical Surveys (DGGS) and the Geophysical Institute, University of Alaska Fairbanks, undertook an assessment of the states geothermal resources under a program jointly sponsored by the U.S. Department of Energy and the State of Alaska. During this period, reconnaissance investigations of more than 100 thermal spring sites and fumarole fields located in Alaska were conducted by DGGS.
This dataset consists of the vector digital GIS files that were used to create sheet 1 of the "Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska" (DGGS RI 2004-3). The map area is centered around Okmok Volcano, on eastern Umnak Island. The data includes volcano-hazard zones for ballistics, ash accumulation, pyroclastic flows, floods and lahars, and debris avalanches. Also included in the dataset are roads, trails, seismic station locations, continuous GPS station locations, creeks, and the location of the Fort Glenn airstrip.
The data table consists of a compilation of sea otter survey results from Bering Island, Russia and select Western Aleutian Islands conducted between 1959 and 2015. The counts were reduced to sea otters per kilometer of coastline for temporal comparability. A correction factor of 3.6 was applied to aerial survey totals to yield results comparable to skiff based surveys. The data table provides the island, year, mode (aerial, skiff, or ground), and shore length covered in each survey. Counts of independent otters and pups are provided if available. Total otters counted or calculated with the correction factor and the calculated linear density are also provided.
Categories: Data;
Tags: Adak Island, Alaska,
Aleutian Islands,
Amchitka Island, Alaska,
Attu Island, Alaska,
Bering Island, Russia,
This data lists the historically active volcanoes of Alaska, their location in latitude/longitude decimal degrees, and the year of the last major eruptive event. The 52 volcanoes listed meet at least one of the following criteria since 1700 CE: (1) documented, unquestioned eruption, or (2) a strongly suspected eruption, often an eruption documented in the historical account with very little information (current geologic knowledge must not contradict the eruption account), or (3) persistent (usually on the order of decades, but certainly longer than several months) fumaroles, with temperatures (where measured) within ~10°C of the boiling point, or (4) significant, measured, volcanic-related, non-eruptive deformation,...
The data consist of counts of kelps and estimated percent cover of fleshy red algae, other benthic algal cover, and non-motile invertebrates in quadrats from over 600 nearshore rocky bottom sites that were sampled by scuba between 1987 and 2021. The sites are from 38 locations on the north Pacific Rim ranging from Bering Island, along the Aleutian Island chain and the Alaska Peninsula to southeast Alaska. At each site, divers counted kelps and estimated percent cover of other algae and encrusting invertebrates in 20 quadrats along 20-25-foot depth contour. At a subset of sites, 40-foot depths were targeted. Quadrat size is specified in the data table but was 0.25 m2 at almost all sites. At the same sites where kelps...
Categories: Data;
Tags: Aleutian Islands,
Gulf of Alaska,
Marine Nearshore Subtidal,
Russia,
Southeast Alaska,
The Alaska Volcano Observatory (AVO) uses an informal set of names for about 140 'volcanoes.' Some names refer to large, complex volcanic centers, while others indicate only a specific cone. This publication expands the list of 140 named volcanoes to include all volcanic vents where magma has reached the surface over the past 2.6 million years. This database of all known (published, or unpublished with permission) Quaternary volcanic vents was developed to better describe the nature and character of Quaternary volcanism in Alaska and specifically to aid in the discussion of spatial and temporal patterns of Alaska volcanism. This list is a preliminary starting point, and we hope that it is updated and expanded by...
This dataset comprises the locations of volcanoes and volcanic centers in Alaska.
Potential tsunami hazards for the Alaska Peninsula communities of King Cove and Cold Bay were evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources and taking into account historical observations. Worst-case hypothetical scenarios are defined by analyzing the tsunami dynamics related to various slip distributions along the Aleutian megathrust. Our results show that the worst-case scenarios for King Cove and Cold Bay are thrust earthquakes in the western Alaska Peninsula region, with magnitudes ranging from Mw 8.9 to Mw 9.3, which have their greatest slip at 10-20 km (6-12 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture...
The 2008 eruption of Kasatochi volcano caused major topographic changes to Kasatochi Island, making all prior topographic maps and data obsolete. The topographic map and data presented here are derived from stereoscopic satellite images acquired on April 18, 2009. Subsequent topographic data has not been acquired, although there has been substantial topographic modification to the island, particularly to the shoreline, since these data were acquired.
This dataset contains digital data that were used for the creation of a geologic map shown in Figure 3 in USGS SIR 2017-5150; Postglacial Eruptive History and Geochemistry of Semisopochnoi Volcano, Western Aleutian Islands, Alaska by Coombs, M.L. and others. The map shows the generalized geology of the island and the locations of stations occupied during field work conducted in the summer of 2005. The data are based on mapping completed during the field work, high-resolution digital imagery, and geochemical and radiometric analyses of rock and soil samples.
With the ending of the Cold War, the US Department of Energy is responsible for the remediation of radioactive waste and disposal of land no longer needed for nuclear material production or related national security missions. The task of characterizing the hazards and risks from radionuclides is necessary for assuring the protection of health of humans and the environment. This is a particularly daunting task for those sites that had underground testing of nuclear weapons, where the radioactive contamination is currently inaccessible. Herein we report on the development of a Science Plan to characterize the physical and biological marine environment around Amchitka Island in the Aleutian chain of Alaska, where three...
Categories: Publication;
Types: Citation;
Tags: Alaska,
Aleutian Islands,
Amchitka Island,
Development,
Science,
This shaded relief image of Okmok Volcano serves as the basemap for sheet 1 of the "Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska" (DGGS RI 2004-3). The map area is centered around Okmok Volcano, on eastern Umnak Island. SRTM and AirSAR DEM datasets were combined in ArcGIS to produce a georeferenced shaded relief TIFF image of Okmok Volcano.
This shapefile is of prospective regional outlines of where marine minerals may occur on the Alaska Outer Continental Shelf (OCS). Polygons were hand digitized based on a U.S. Geological Survey (USGS) data review that considers the state of knowledge regarding marine mineral occurrences within the Alaska OCS. This data release is a companion to the USGS Professional Paper, Gartman and others, 2022. Reference Gartman, A., Mizell, K., and Kreiner, D.C., 2022, Marine minerals in Alaska — A review of coastal and deep-ocean regions: U.S. Geological Survey Professional Paper 1870, 46 p., https://doi.org/10.3133/pp1870.
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