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Photogrammetric digital surface models and orthoimagery for 26 coastal communities of western Alaska
The State of Alaska Division of Geological & Geophysical Surveys acquired photogrammetric digital surface models (DSMs) and co-registered orthorectified aerial images (orthoimages) for the west coast of Alaska in support of coastal vulnerability mapping efforts. This report is a summary of the data collected over 26 developed areas along approximately 3,500 km of coastline in the Bering Sea, Norton Sound, and Yukon-Kuskokwim Delta regions (fig. 1). Aerial photographs were collected between July 31 and September 6, 2015, and processed using Structure from- Motion (SfM) photogrammetry techniques. Ground control points (GCPs) and checkpoints were collected in support of these data products during a Global Navigation...
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...
During 2009, the Alaska Division of Geological & Geophysical Surveys continued a program, begun in 2006, of reconnaissance mapping of surficial geology in the proposed natural-gas pipeline corridor through the upper Tanana River valley. The study area is a 12-mi-wide (19.3-km-wide) area that straddles the Alaska Highway from the western boundaries of the Tanacross B-3 and A-3 quadrangles near Tetlin Junction eastward to the eastern boundaries of the Nabesna D-1 and C-1 quadrangles along the Canada border. Mapping during 2008-2009 in the Tanacross and Nabesna quadrangles linked with the mapping completed in the Tanacross, Big Delta and Mt. Hayes quadrangles in 2006-2008. Surficial geology was initially mapped in...
Aerial photographs of the coastline from Teller to Nome were collected between August 26, 2015 - August 27, 2015. The photographs were processed using Structure-from-Motion (SfM) photogrammetric techniques. Global Positioning System (GPS) checkpoints were collected via a Global Navigation Satellite System (GNSS) survey conducted between August 15 and September 14, 2015. For the purposes of open access to elevation and orthoimagery datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license. Orthoimages contain 4-band, 8-bit, unsigned raster data (red/green/blue/no data; file format-GeoTIFF; source-Fairbanks Fodar) with 20 cm GSD. No-data values are found...
The State of Alaska Division of Geological & Geophysical Surveys (DGGS) produced an orthorectified aerial optical image mosaic (orthoimage) and digital surface model over an area extending from milepost (MP) 17 to approximately MP 24.5 on the Alaska State Highway 7 (Haines Highway) north of Haines along the Chilkat River in southeast Alaska. The aerial photogrammetric survey targeted large debris fans and their alpine source areas on the west side of the Takshanuk Mountains in support of cryosphere hazards mapping and monitoring efforts. Aerial photographs and Global Navigation Satellite System (GNSS) data were collected on May 26, 2014, and were processed using Structure-from-Motion (SfM) photogrammetric techniques...
Photogrammetric digital surface models and orthoimagery for 26 coastal communities of western Alaska
The State of Alaska Division of Geological & Geophysical Surveys acquired photogrammetric digital surface models (DSMs) and co-registered orthorectified aerial images (orthoimages) for the west coast of Alaska in support of coastal vulnerability mapping efforts. This report is a summary of the data collected over 26 developed areas along approximately 3,500 km of coastline in the Bering Sea, Norton Sound, and Yukon-Kuskokwim Delta regions (fig. 1). Aerial photographs were collected between July 31 and September 6, 2015, and processed using Structure from- Motion (SfM) photogrammetry techniques. Ground control points (GCPs) and checkpoints were collected in support of these data products during a Global Navigation...
Aerial photographs of the coastline from Nome to Elim were collected on August 23, 2015. The photographs were processed using Structure-from-Motion (SfM) photogrammetric techniques. Global Positioning System (GPS) checkpoints were collected via a Global Navigation Satellite System (GNSS) survey conducted between August 15 and September 14, 2015. For the purposes of open access to elevation and orthoimagery datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license. This file is a single-band, 32-bit float DSM (digital surface model) which represents surface elevations of buildings, vegetation, and uncovered ground surfaces in meters with 20 cm GSD. The...
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,...
In August 2013, a helicopter-based crew photographed approximately 52 miles (84 km) of shoreline near Port Heiden, Alaska, from 7 miles (11 km) northeast of Reindeer Creek, known locally as North Creek, to 10 miles (16 km) southwest of Strogonof Point. During this flight, 1,441 oblique aerial photographs were collected and were spatially referenced using a Garmin Dakota 20 handheld GPS. For a complete description of the image collection and file organization process please see the detailed metadata associated with this Raw Data File.
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 1:50,000 scale geologic map describes the distribution of unconsolidated deposits, identifies local geologic hazards, and provides information about the depositional environment and basic engineering properties of common surficial-geologic materials in and around Shaktoolik, Alaska. Map units are the result of combined field observations and aerial imagery interpretation. A suite of local ground observations were collected over a two-week period in July 2011 by a helicopter-supported team of DGGS geologists and collaborators. Field investigations included soil test pits, sample collection, soil and rock description, oblique aerial photography, and documentation of landscape morphology.
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...
The State of Alaska Division of Geological & Geophysical Surveys (DGGS) produced a digital surface model (DSM) and an orthorectified aerial optical image mosaic (orthoimagery) of the Resurrection Bay watershed, surrounding the city of Seward in south-central Alaska. Aerial photographs and Global Navigation Satellite System (GNSS) data were collected on August 13, 2015, and were processed using Structure-from-Motion (SfM) photogrammetric techniques to create the DSM and orthoimagery. All data are projected in UTM Zone 6 North (meters) using the NAD83 (2011; EPSG 26906) horizontal datum and NAVD88 (Geoid12A; EPOCH 2010.00) vertical datum. The project was part of an ongoing investigation of the impact of flooding,...
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....
The purpose of this study is to evaluate potential tsunami hazards for the community of Whittier and western Passage Canal area. We numerically model the extent of inundation due to tsunami waves generated from earthquake and landslide sources. Tsunami scenarios include a repeat of the tsunami triggered by the 1964 Great Alaska Earthquake, as well as tsunami waves generated by a hypothetically extended 1964 rupture, a hypothetical Cascadia megathrust earthquake, hypothetical earthquakes in Prince William Sound, and Kodiak asperities of the 1964 rupture. Local underwater landslide and rockslide events in Passage Canal are also considered as credible tsunamigenic scenarios. Results of numerical modeling combined with...
Aerial photographs of the coastline from Wales to Teller were collected on August 27, 2015 - August 28, 2015. The photographs were processed using Structure-from-Motion (SfM) photogrammetric techniques. Global Positioning System (GPS) checkpoints were collected via a Global Navigation Satellite System (GNSS) survey conducted between August 15 and September 14, 2015. For the purposes of open access to elevation and orthoimagery datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license. Orthoimages contain 4-band, 8-bit, unsigned raster data (red/green/blue/no data; file format-GeoTIFF; source-Fairbanks Fodar) with 20 cm GSD. No-data values are found...
The State of Alaska Division of Geological & Geophysical Surveys (DGGS) produced a digital surface model (DSM) and an orthorectified aerial optical image mosaic (orthoimagery) of the Resurrection Bay watershed, surrounding the city of Seward in south-central Alaska. Aerial photographs and Global Navigation Satellite System (GNSS) data were collected on August 13, 2015, and were processed using Structure-from-Motion (SfM) photogrammetric techniques to create the DSM and orthoimagery. All data are projected in UTM Zone 6 North (meters) using the NAD83 (2011; EPSG 26906) horizontal datum and NAVD88 (Geoid12A; EPOCH 2010.00) vertical datum. The project was part of an ongoing investigation of the impact of flooding,...
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