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The purpose of this study is to evaluate tsunami hazard for the community of Seward and northern Resurrection Bay area, Alaska. This report will provide guidance to local emergency managers in tsunami hazard assessment. We used a numerical modeling method to estimate the extent of inundation by tsunami waves generated from earthquake and landslide sources. Our tsunami scenarios included a repeat of the tsunami of the 1964 Great Alaska Earthquake, as well as tsunami waves generated by two hypothetical Yakataga Gap earthquakes in northeastern Gulf of Alaska, hypothetical earthquakes in Prince William Sound and Kodiak asperities of the 1964 rupture, and local underwater landslides in Resurrection Bay. Results of numerical...
Potential tsunami hazards for the Fox Islands communities of Unalaska/Dutch Harbor and Akutan 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 results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Aleutian megathrust. The worst-case scenarios for Unalaska and Akutan are thought to be thrust earthquakes in the Fox Islands region with magnitudes ranging from Mw 8.8 to Mw 9.1 that have their greatest slip at 30-40 km (18-25 mi) depth. We also consider Tohoku-type ruptures and an outer-rise...
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...
The 0.53-second Sitka Alaska Digital Elevation Model provides bathymetric and topographic data in ASCII raster format of 0.53-second resolution in geographic coordinates.
Subaerial landslides at the head of Barry Arm Fjord in southern Alaska could generate tsunamis (if they rapidly failed into the Fjord) and are therefore a potential threat to people, marine interests, and infrastructure throughout the Prince William Sound region. Knowledge of ongoing landslide movement is essential to understanding the threat posed by the landslides. Because of the landslides' remote location, field-based ground monitoring is challenging. Alternatively, periodic acquisition and interferometric processing of satellite-based synthetic aperture radar data provide an accurate means to remotely monitor landslide movement. Interferometric synthetic aperture radar (InSAR) uses two Synthetic Aperture...
In May 2014 the Geophysical Institute at the University of Alaska Fairbanks (UAF) developed integrated bathymetricâtopographic digital elevation models (DEMs) of Skagway and Haines, Alaska, for the National Tsunami Hazard Mitigation Program (NTHMP). The DEMs are designed to fit within a nested hierarchy of similar DEMs of larger spatial extent but coarser resolution. The gridded DEMs will be used to support modeling of tsunami generation, propagation, and inundation. This report describes the various source datasets, data processing tasks and techniques, the surface interpolation, and quality assessment of the seamless 8/15-arcâsecond (~15 m) bathymetric-topographic DEMs. The data files are provided as ASCII...
Between 27 and 11 kyr ago, during the last major (Naptowne) glaciation, the northwestern and western Kenai Peninsula and the Cook Inlet trough were covered by ice except for local nunataks and small refugia, like the Caribou Hills. Landforms related to four glacial stades are recognized and paleogeographic maps document ice limits, drainage systems, glacial-impounded lakes, and glaciomarine terraces. Numerous multidisciplinary studies of glacial, vegetation, and insect histories document Holocene climatic changes.
Summary This data release contains postprocessed model output from a simulation of hypothetical rapid motion of landslides, subsequent wave generation, and wave propagation. A simulated displacement wave was generated by rapid motion of unstable material into Barry Arm fjord. We consider the wave propagation in Harriman Fjord and Barry Arm, western Prince William Sound (area of interest and place names depicted in Figure 1). We consider only the largest wave-generating scenario presented by Barnhart and others (2021a, 2021b). As in Barnhart and others (2021c), we used a simulation setup similar to Barnhart and others (2021a, 2021b), but our results differ because we used different topography and bathymetry datasets....
Categories: Data;
Types: Downloadable,
GeoTIFF,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Raster,
Shapefile;
Tags: Alaska,
Barry Arm,
D-Claw,
Geomorphology,
Marine Geology,
Subaerial landslides at the head of the Barry Arm fjord remain a tsunami threat for the Prince William Sound region in southern Alaska. Tasked RADARSAT-2 synthetic aperture radar (SAR) data from two ultrafine beam modes (2 m), U19 and U15, were used to measure landslide movement of slopes near the toe of the Barry Glacier between 21 May 2021 and 5 November 2021. Data were acquired every 24 days, with U19 beginning on 21 May 2021 and U15 beginning on 28 May 2021. For a few planned acquisition dates, scenes were not captured because of technical issues. Interferometric synthetic aperture radar (InSAR) deformation maps (interferograms) are provided in wrapped phase (line-of-sight (LOS) phase in radians between 0 and...
This data release contains four GIS shapefiles, one Google Earth kmz file, and five metadata files that summarize results from Interferometric Synthetic Aperture Radar (InSAR) analyses in the Glacier Bay region of Alaska and British Columbia. The principal shapefile (Moving_Ground) and the kmz file (GBRegionMovingGround) contain polygons delineating slow-moving (0.5-6 cm/year in the radar line-of-sight direction) landslides and subsiding fan deltas in the region. Landslides and fan deltas were identified from displacement signals captured by InSAR interferograms of Sentinel-1 C-band Synthetic Aperture Radar images. The images were acquired at 12-day intervals from June to October from 2018 to 2020. We applied the...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Alaska,
Climate change,
Climatology,
Geomorphology,
Glacial geology,
This data release contains model output from simulations presented in the associated Open-File Report (Barnhart and others, 2021). In this report, we present model results from four simulations (scenarios C-290, NC-290, C-689, NC-689, Table 1) of hypothetical rapid movement of landslides into adjacent fjord water at Barry Arm, Alaska using the D-Claw model (George and Iverson, 2014; Iverson and George, 2014). The basis for the four scenarios is described in Barnhart and others (2021). Table 1. Summary of four considered scenarios including key simulation input parameter values. Simulation input parameters Scenario name and description NC-290 C-290 NC-689 C-689 Symbol Units Description Smaller,...
Categories: Data;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Alaska,
Barry Arm,
D-Claw,
Geomorphology,
Geophysics,
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...
In this report, we evaluate potential tsunami hazards for southeastern Alaska communities of Elfin Cove, Gustavus, and Hoonah and numerically model the extent of inundation from tsunami waves generated by tectonic and landslide sources. We perform numerical modeling of historic tsunami events, such as the tsunami triggered by the 1964 Great Alaska Earthquake, and the tsunami waves generated by the recent 2011 Tohoku and 2012 Haida Gwaii earthquakes. Hypothetical tsunami scenarios include variations of the extended 1964 rupture, megathrust earthquakes in the Prince William Sound and Alaska Peninsula regions, and a Cascadia megathrust earthquake. Local underwater landslide events in Taylor Bay and Port Frederick,...
Summary This data release contains postprocessed model output from simulations of hypothetical rapid motion of landslides, subsequent wave generation, and wave propagation. A modeled tsunami wave was generated by rapid motion of unstable material into Barry Arm Fjord. This wave propagated through Prince William Sound and then into Passage Canal east of Whittier. Here we consider only the largest wave-generating scenario presented by Barnhart and others (2021a, 2021b) and use a simulation setup similar to that work. The results presented here are not identical to those presented in Barnhart and others (2021a, 2021b) because the results in this data release were obtained using an expanded dataset of topography and...
Categories: Data;
Types: Downloadable,
GeoTIFF,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Raster,
Shapefile;
Tags: Alaska,
Barry Arm,
D-Claw,
Geomorphology,
Marine Geology,
We evaluate potential tsunami hazards for the city of Valdez and numerically model the extent of inundation from tsunamis generated by earthquake and landslide sources. Tsunami scenarios include a repeat of the tsunami triggered by the 1964 Great Alaska Earthquake, as well as hypothetical tsunamis generated by an extended 1964 rupture, a Cascadia megathrust earthquake, and earthquakes from the Prince William Sound and Kodiak asperities of the 1964 rupture. Local underwater landslide events in Port Valdez are also considered as credible tsunamigenic scenarios. Results of numerical modeling are verified by simulating the tectonic and landslide-generated tsunamis in Port Valdez observed during the 1964 earthquake....
This work integrated multiple topographic and bathymetric data sources to generate a merged topobathymetric map of western Prince William Sound. We converted all data sources to NAD 83 UTM Zone 6 N and mean higher high water (MHHW) before compiling. In Barry Arm, north of Port Wells, we used a digital terrain model (DTM) derived from subaerial light detection and ranging (lidar) data collected on June 26, 2020, (Daanen and others, 2021) and submarine multibeam sonar bathymetric data collected between August 12 and 23, 2020 (NOAA, 2020). In College Fiord, adjacent to Barry Arm to the east, we used multibeam sonar bathymetric data collected between March 25 and August 26, 2021 (NOAA, 2021). These data were combined...
Categories: Data;
Types: Downloadable,
GeoTIFF,
Map Service,
Raster;
Tags: Alaska,
Barry Arm,
D-Claw,
Geomorphology,
Marine Geology,
Potential tsunami hazards for the community of Chenega Bay, located on Evans Island between Sawmill and Crab bays, were evaluated by numerically modeling the extent of inundation from tsunami waves generated by earthquakes. Tsunami scenarios include a repeat of the tsunami triggered by the 1964 Great Alaska Earthquake, as well as tsunamis generated by a hypothetically extended 1964 rupture, a hypothetical Cascadia megathrust earthquake, a hypothetical earthquake in the Kodiak asperity of the 1964 rupture, and a hypothetical Tohoku-type rupture in the Gulf of Alaska region. Results of numerical modeling are verified by simulations of the tectonic tsunami observed in Chenega Cove during the 1964 earthquake. The results...
In this report we evaluate potential tsunami hazards for the southeastern Alaska community of Yakutat and numerically model the extent of inundation from tsunami waves generated by tectonic and landslide sources. We use numerical modeling of historical tsunami events at Yakutat, such as the tsunami triggered by the 1964 Great Alaska Earthquake, and the tsunami waves generated by the recent 2011 Tohoku earthquake, to verify the tsunami model. Potential hypothetical tsunami sources include variations of the extended 1964 rupture, megathrust earthquakes in the Prince William Sound and Alaska Peninsula regions, and earthquakes in the Yakataga-Yakutat area, including the historical September 10, 1899, earthquake. Local...
Tags: Tsunami,
geoscientificInformation
The purpose of this study was to evaluate a potential tsunami risk for communities of Homer and Seldovia in the Kachemak Bay area, Alaska. This report provides guidance to the local emergency managers in tsunami hazard assessment. We used a numerical modeling method to estimate the extent of inundation due to tsunami waves generated by earthquake sources. Our tsunami scenarios included a repeat of the tsunami of the 1964 great Alaska earthquake, as well as a hypothetical tsunami wave generated by a local fault source. We didn't consider landslide-generated tsunamis in this study. Results of numerical modeling combined with historical observations in the region are intended to help local emergency services officials...
In this report, we evaluate potential tsunami hazards for the southeastern Alaska community of Juneau and numerically model the extent of inundation from tsunami waves generated by tectonic and submarine landslide sources. We calibrate our tsunami model by numerically simulating the 2011 Tohoku tsunami at Juneau and comparing our results to instrument records. Analysis of calculated and observed water level dynamics for the 2011 event in Juneau reveals that the model underestimates the observed wave heights in the city by a factor of two, likely due to complex tsunami-tide interactions. We compensate for this numerical underestimation by doubling the coseismic slip of the hypothetical tsunami sources in our models....
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