The Alaska Division of Geological & Geophysical Surveys (DGGS) used lidar to produce digital terrain models (DTM), a digital surface model (DSM), and an intensity model for Homer, Alaska. Detailed bare earth elevation data for Homer were collected and processed for use in a landslide hazard resiliency project for the City of Homer. Data coverage includes neighboring Kachemak City. Lidar and Global Navigation Satellite System (GNSS) data were collected on June 3, 2019, and subsequently processed using TerraSolid and ArcGIS. The Alaska Division of Mining Land & Water (DMLW) Survey Section conducted a targeted Ground Control Survey for this project on June 19-20, 2019. These data are being released as a Raw Data File with an open end-user license. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30591).

Landslide hazard susceptibility mapping in Haines, Alaska, Report of Investigation 2024-8, provides a map and database of historical and prehistoric slope failures, maps of shallow and deep-seated landslide susceptibility, and a map of simulated debris flow runouts for the city and borough of Haines, Alaska. This work was prompted by the deadly Beach Road landslide that occurred on December 2, 2020, in Haines, Alaska, which highlights the significant safety and financial risks posed by slope failures to people and infrastructure. To better inform the Haines Borough of their potential landslide hazards and increase the city's hazard resiliency, the Alaska Division of Geological & Geophysical Surveys (DGGS) developed maps of historical and prehistorical slope failures, shallow landslide susceptibility, and modeled debris flow runouts. DGGS staff created a shallow landslide susceptibility map following protocols like those developed by the Oregon Department of Geology and Mineral Industries, which includes incorporating landslide inventory data, geotechnical soil properties, and lidar-derived topographic slope to calculate the Factor of Safety (FOS), which serves as a proxy for landslide susceptibility. Debris flow runout extents were generated using the model Laharz, which simulates runout extents based on catchment-specific physical parameters (e.g., hypothetical sediment volumes). Data from these analyses are collectively intended to depict locations where landslides are relatively more likely to occur or are relatively more likely to travel. The results provide important hazard information that can help guide planning and future risk investigations. The maps are not intended to predict slope failures and are site-specific; detailed investigations should be conducted before development in vulnerable areas. Results are for informational purposes and are not intended for legal, engineering, or surveying uses. These data and the interpretive maps and report are available from the DGGS website: http://doi.org/10.14509/31309.

Report of Investigation 2019-6A, Addendum A: Regional tsunami hazard assessment for Pasagshak, Alaska, provides an estimated extent of the tsunami hazard zone in the community of Pasagshak, Alaska. Pasagshak is a small community on Kodiak Island, about 70 km (44 mi) south of Kodiak. The highest resolution bathymetric grid that covers this community is the level 3 grid with a grid size of about 45x82 m. We estimate the extent of the tsunami hazard zone in Pasagshak by running all nine tsunami scenarios described in the main report (Report of Investigation 2019-6). Each model run was performed for 12 hours of tsunami propagation to account for all waves in the wave train, including any secondary (reflected) waves. The maximum value of the tsunami height based on a composite of all scenarios, multiplied by a safety factor of 1.3, results in a maximum estimated runup height of 39 m (128 ft) for the community of Pasagshak. We illustrate the maximum estimated tsunami runup on land by drawing an elevation contour on the 5-m (16-ft) resolution community topographic map that corresponds to the maximum modeled wave height offshore. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/30763.

Tsunami inundation maps of Anchorage and upper Cook Inlet, Alaska, Report of Investigation 2023-2, evaluates potential tsunami hazards for upper Cook Inlet, including Anchorage, Girdwood, and Hope, Alaska, by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquakes. We define an updated suite of earthquakes, including Tohoku-style megathrust ruptures and other sources in the eastern part of the Alaska-Aleutian megathrust, to calculate vertical seafloor displacements and model resulting tsunami dynamics. We also perform a numerical analysis of tsunami-tide interactions for the 1964 Great Alaska Earthquake in upper Cook Inlet, an area with some of the most extreme tidal ranges in the U.S. This analysis reveals why the 1964 earthquake-generated tsunami largely went undetected in upper Cook Inlet and highlights that the tidal stage at the time of future great earthquakes determines the severity of tsunami impacts around Anchorage. A rare combination of earthquake magnitude, location, and timing must be satisfied for tsunami wave energy to reach upper Cook Inlet coincident with a natural high tide. A hypothetical earthquake with maximum slip distributed between depths of 17 and 32 km (10.6 and 19.9 mi) results in worst case tsunami inundation for Anchorage. If the tsunami arrives to the Anchorage area at high tide, the maximum predicted overland flow depths in the community can reach up to 10 m (32.8 ft), and the currents could be as strong as 4 m/sec (7.8 knots). Dangerous wave activity is expected to last for more than 24 hours. The results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami damage. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/31018.

The Division of Geological & Geophysical Surveys has analyzed long-term shoreline change at 48 Alaska communities. Shoreline datasets were compiled from previously published U.S. Geological Survey assessments and created from historical and recent aerial images by the Alaska Division of Geological & Geophysical Surveys. Shorelines were analyzed to calculate shoreline change rates every 25 meters along coastlines and tidally influenced riverbanks using the Digital Shoreline Analysis System (DSAS; Himmelstoss and others, 2018). The geodatabase for each community includes shoreline positions, the alongshore baseline used to cast transects, and transects that include shoreline change rates and statistics. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30552).

Seward Peninsula airborne electromagnetic survey, Kigluiak, Bendeleben, and Darby Mountains, Geophysical Report 2024-2, covers parts of the Teller, Bendeleben, Nome, and Solomon 1:250,000-scale U.S. Geological Survey (USGS) quadrangles on the Seward Peninsula north of Nome, Alaska. Time-domain electromagnetic data were collected with the SkyTEM 306HP system, which was towed by a helicopter, from September 8 to October 3, 2023, and from June 5 to July 18, 2024. A total of 4,330-line kilometers (km) were collected covering 4,817 km2. The survey was flown with semi-parallel lines spaced approximately 1 km apart and oriented perpendicular to regional geologic strike. Electromagnetic data were used to create resistivity models. The data, as well as additional metadata, are available from the DGGS website: http://doi.org/10.14509/31303.

The Division of Geological & Geophysical Surveys has analyzed long-term shoreline change at 48 Alaska communities. Shoreline datasets were compiled from previously published U.S. Geological Survey assessments and created from historical and recent aerial images by the Alaska Division of Geological & Geophysical Surveys. Shorelines were analyzed to calculate shoreline change rates every 25 meters along coastlines and tidally influenced riverbanks using the Digital Shoreline Analysis System (DSAS; Himmelstoss and others, 2018). The geodatabase for each community includes shoreline positions, the alongshore baseline used to cast transects, and transects that include shoreline change rates and statistics. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30552).

The Division of Geological & Geophysical Surveys has analyzed long-term shoreline change at 48 Alaska communities. Shoreline datasets were compiled from previously published U.S. Geological Survey assessments and created from historical and recent aerial images by the Alaska Division of Geological & Geophysical Surveys. Shorelines were analyzed to calculate shoreline change rates every 25 meters along coastlines and tidally influenced riverbanks using the Digital Shoreline Analysis System (DSAS; Himmelstoss and others, 2018). The geodatabase for each community includes shoreline positions, the alongshore baseline used to cast transects, and transects that include shoreline change rates and statistics. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30552).

The Division of Geological & Geophysical Surveys has analyzed long-term shoreline change at 48 Alaska communities. Shoreline datasets were compiled from previously published U.S. Geological Survey assessments and created from historical and recent aerial images by the Alaska Division of Geological & Geophysical Surveys. Shorelines were analyzed to calculate shoreline change rates every 25 meters along coastlines and tidally influenced riverbanks using the Digital Shoreline Analysis System (DSAS; Himmelstoss and others, 2018). The geodatabase for each community includes shoreline positions, the alongshore baseline used to cast transects, and transects that include shoreline change rates and statistics. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30552).