Bender, Adrian M. (ORCID: 0000-0001-7469-1957) Haeussler, Peter J. (ORCID: 0000-0002-1503-6247) Powers, Peter M. (ORCID: 0000-0003-2124-6184) 20210510 vector and tabular digital data Geologic Inputs for the 2023 Alaska Update to the U.S. National Seismic Hazard Model (NSHM) ver 2.0, February 2023 Anchorage, Alaska U.S. Geological Survey, Alaska Science Center Suggested Citation: Bender, A.M, Haeussler, P.J., Powers, P.M., 2021, Geologic inputs for the 2023 Alaska update to the U.S. National Seismic Hazard Model (NSHM) (ver 2.0, February 2023): U.S. Geological Survey data release, https://doi.org/10.5066/P97NRR0F https://doi.org/10.5066/P97NRR0F This data release is composed of three crustal (as opposed to subduction zone) geologic input datasets for the 2023 Alaska update to the U.S. National Seismic Hazard Model (NSHM): 1) fault section vector line data, 2) fault zone vector polygon data, and 3) accompanying earthquake geology attributes. The purpose of this data release is to provide geospatial data of crustal fault and fold lines and zones with slip rates and structural geometries as foundational geologic inputs for modeling seismic hazard in the 2023 National Seismic Hazard Map update for Alaska. This version reflects input by the community of USGS, State, and academic scientists as well as geotechnical engineers and stakeholders following a public workshop held May 27, 2021. 2023 publication date Complete None planned -165.92 -130.15 70.75 50.39 USGS Metadata Identifier USGS:ASC371 ISO 19115 Topic Category GeoScientificInformation NASA GCMD Earth Science Keyword Thesaurus Earth science Tectonic Landforms Faults Tectonic Processes USGS Thesaurus Geology Structural geology Paleoseismology USGS Geographic Names Information System (GNIS) Alaska Alaska Range Brooks Range Yukon No access constraints. No use constraints. These data are marked with a Creative Common CC0 1.0 Universal License and are in the public domain. It is requested that this USGS data release be cited for any subsequent publications that reference or utilize these data. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. U.S. Geological Survey, Alaska Science Center Mailing and Physical

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Anchorage Alaska 99508 USA 907-786-7000 gs-ak_asc_datamanagers@usgs.gov Adrian Bender conducted the mapping and data compilation to prepare these datasets. Peter Haeussler and Peter Powers supervised the dataset preparation. Evan Thoms, Camille Collett, and Dennis Walworth reviewed the data release. U.S. Geological Survey 2020 website online U.S. Geological Survey U.S. Geological Survey, 2020, U.S. Quaternary Faults Interactive Fault Map: https://doi.org/10.5066/F7S75FJM https://www.usgs.gov/natural-hazards/earthquake-hazards/faults U.S. Geological Survey 2020 Vector digital data online U.S. Geological Survey U.S. Geological Survey, 2020, Quaternary Fault and Fold Database for the Nation, https://doi.org/10.5066/P9BCVRCK https://doi.org/10.5066/P9BCVRCK U.S. Geological Survey 2022 website online U.S. Geological Survey U.S. Geological Survey - Earthquake Hazards, 2022, National Seismic Hazard Model, last updated March 9, 2022 https://www.usgs.gov/programs/earthquake-hazards/science/national-seismic-hazard-model Where applicable, attribute values in this dataset were cross-referenced for accuracy and consistency with attributes in the U.S. Geological Survey Quaternary Fault and Fold Database (QFFD). Attribute values are internally consistent between the three datasets contained in this release, and are consistent with values stored in the U.S. Geological Survey Quaternary Fault and Fold Database (QFFD). Within this data release, the dataset NSHM2023_Alaska_FaultSections contains a map of lines simplified from the U.S. Geological Survey Quaternary Fault and Fold Database (QFFD). Simplification was executed for modeling purposes (downstream in the NSHM workflow) and involves removal of faults or folds with length less than 5 kilometers, manual consolidation of faults expressed as many small short features with line ends within 5 kilometers into continuous lines, and manual reduction of line vertex spacing to between 1 and 10 km to preserve essential strike changes with as few vertices as possible. The 10 km upper vertex spacing limit approximates half the thickness of the seismogenic crust. The positional accuracy of the fault trace linework reflects the 1:500,000 scale of the map. Mapped lines generally occur within 50 m of the fault trace lines archived in QFFD, which approximate the real-world position of the faults. U.S. Geological Survey 2017 Vector digital data online U.S. Geological Survey U.S. Geological Survey and Alaska Department of Natural Resources, Quaternary fault and fold database, accessed March 3, 2021 at: https://www.usgs.gov/natural-hazards/earthquake-hazards/faults https://www.usgs.gov/natural-hazards/earthquake-hazards/faults online database 2021 access date Quaternary Fault and Fold Database (QFFD) Detailed fault and fold linework used to derive the simplified fault and deformation zones contained in this data release. Accessed and downloaded QFFD data Quaternary Fault and Fold Database (QFFD) Unknown Used ESRI ArcMap (version 10.8.1) software to simplify (1:500,000 scale) lines >5 kilometers where State=Alaska in QFFD. Reduced line vertex spacing to between 1 and 10 kilometers in order to preserve key strike changes while using as few vertices as possible with a maximum spacing equivalent to half the thickness of Earth's seismogenic crust. For faults and folds with published active deformation rates and structural geometry information, we attributed the fault section lines with these data. Otherwise we attributed the fault sections with categorical data contained in the QFFD. Quaternary Fault and Fold Database (QFFD) Unknown Used ESRI ArcMap (version 10.8.1) software to generate polygon zones around fault and fold lines with some combination of inadequate length (<5 km) or ambiguous rate/timing of activity that precluded inclusion in the Fault Sections model as a line. Quaternary Fault and Fold Database (QFFD) Unknown Used ESRI ArcMap (version 10.8.1) software to generate centroid points of lines in the Fault Sections model to generate a table with additional data about each fault included in the Fault Sections model. Added latitude and longitude coordinates for each point and exported the attribute table as comma separated values file. QFFD Unknown LITERATURE CITED: Aki, K., Richards, P.G., 1980. Quantitative Seismology: Theory and Methods. W.H. Freeman, San Francisco Unknown U.S. state and Canadian province provide geographic name reference. Vector String 105 0.000000001 0.000000001 Decimal degrees World Geodetic System of 1984 (WGS84) World Geodetic System of 1984 (WGS84) 6378137 298.257223563 [FOLDER] NSHM2023_Alaska_FaultSections.zip Vector geospatial data mapping Alaska fault sections, including fault section attributes. Lines are simplified from active fault and fold traces mapped and archived in the Quaternary Fault and Fold Database of the United States (QFFD) and original studies cited in the companion table "NSHM2023_Alaska_EQGeoDB.csv". The purpose of this database is to provide geology-based fault and fold lines, rates, and geometries for modeling earthquake hazard in the 2023 NSHM update for Alaska. Provided in Esri shapefile (SHP), KML, and GeoJSON formats. Author defined FID Internal ESRI feature number ESRI 0 104 Shape Feature geometry ESRI Polyline Vector geospatial polyline ESRI name Unique fault section name. Corresponds to the 'name' field in the "NSHM2023_Alaska_EQGeoDB.csv" file, included with this data package. Quaternary Fault and Fold Database (QFFD) Unique fault section name. state State or Province in which fault section occurs Author defined AK The state of Alaska, United States of America Author defined YT The province of Yukon, Canada Author defined BC The province of British Columbia, Canada Author defined dip Fault dip in degrees from horizontal. If dip is based on published observations (i.e., not assumed based on slip sense), the reference is cited in the 'DipRef' field of the "NSHM2023_Alaska_EQGeoDB.csv" table, included with this data package. Author defined 5 90 Degrees rake Fault rake in degrees (between 180 and -180) representing the direction of fault slip according to the right-hand rule convention of Aki and Richards (1980). Author defined -90 180 degrees upperDepth Upper depth of fault in kilometers. This is primarily a place keeper field for subsequent applications; most entries from geologic inputs are 0. Author defined Upper depth of fault in kilometers. lowerDepth Lower depth of fault in kilometers. This is primarily a place keeper field for subsequent applications; most entries from geologic inputs are 0. Author defined Lower depth of fault in kilometers. rateType Indicates whether entry in 'rate' field represents fault-parallel (SLIP_RATE) or vertical (VERTICAL_SLIP_RATE) rate of fault offset. Author defined SLIP_RATE Entry in 'rate' field represents fault-parallel slip Author defined VERTICAL_SLIP_RATE Entry in 'rate' field represents vertical motion Author defined NOMINAL Entry reflects an assigned nominal rate matching the lower QFFD rate bin that the authors deemed suitable based on fault expression. Author defined FaultID Unique identifying number for each fault section. Corresponds to the 'FaultID' field in the "NSHM2023_Alaska_EQGeoDB.csv" file, included with this data package. Author defined Unique identifying number for each fault section. rate Vertical or fault-parallel slip rate in mm/yr, corresponds to the 'Rate' field in the table "NSHM2023_Alaska_EQGeoDB.csv" included with this data package. Based on 'RateData' and 'RateRef' in table. Author defined 0.01 54.4 millimeters per year [FOLDER] NSHM2023_Alaska_FaultZones.zip Vector geospatial data mapping Alaska fault zones. These are Polygon zones covering regions of diffuse or low-rate deformation. Zones defined based on active fault and fold traces mapped and archived in the QFFD and original studies cited in the companion table "NSHM2023_Alaska_EQGeoDB.csv". Provided in Esri shapefile (SHP), KML, and GeoJSON formats. Author defined FID Internal ESRI feature number ESRI 0 3 Shape Feature geometry ESRI Polygon Vector geospatial polygon ESRI Id Sequential record identifier Author defined Sequential record identifier name Unique fault zone polygon name. Author defined Fault zone name state State or Province in which fault zone occurs Author defined AK The state of Alaska, United States of America Author defined YT The province of Yukon, Canada Author defined BC The province of British Columbia, Canada Author defined NSHM2023_Alaska_EQGeoDB.csv Table that documents the sources for geologic rate and geometry inputs to the fault sections in the "NSHM2023_Alaska_FaultSections" vector geospatial data. Files can joined using the 'FaultID' or 'Name' field. These data can also be displayed independently as points with coordinates of the fault section line midpoint (CentLat, CentLong). Presented in a Comma Separated Value (CSV) formatted table. Author defined FaultID Unique identifying number for each fault section. Corresponds to the 'FaultID' field in the "NSHM2023_Alaska_FaultSections" vector geospatial data, included with this data package. Author defined Unique identifying number for each fault section. Name Unique fault section name. Corresponds to the 'name' field in the "NSHM2023_Alaska_FaultSections" vector geospatial data, included with this data package. Quaternary Fault and Fold Database (QFFD) Unique fault section name. state State or Province in which fault section occurs Author defined AK The state of Alaska, United States of America Author defined YT The province of Yukon, Canada Author defined BC The province of British Columbia, Canada Author defined CentLat Latitude of the midpoint of each fault section line. Derived from the "NSHM2023_Alaska_FaultSections" file, included with this data package. Author defined 53.2316 70.5277 Decimal degrees (WGS 1984) CentLong Longitude of the midpoint of each fault section line. Derived from the "NSHM2023_Alaska_FaultSections" file, included with this data package. Author defined -165.413 -132.8902 Decimal degrees (WGS 1984) RateData This field describes slip rate source data. If the slip rate is derived from a field study, the entry is "slip rate study". If a categorical rate is applied, the entry is "QFFD slip rate bin lower bound". If rate represents balance between rates of kinematically adjacent structures, the entry is "rate balanced". Author defined slip rate study Slip rate is derived from field data. Citation to the referenced study provided in the 'RateRef' field of this table. Author defined QFFD slip rate bin lower bound Slip rate entry is a categorical lower QFFD bin rate bound. Author defined rate balanced Rate entry represents balance between rates of kinematically adjacent structures. Author defined nominal assigned value Rate entry is assigned lower QFFD value consistent with fault expression in the absence of extant rate constraint. Author defined Rate Slip rate in mm/yr selected based on RateData and RateRef. Author defined 0.01 54.4 millimeters per year RateRef Reference for the source used to derive the 'rate' entry. Author defined 'RateData' = "slip rate study" Citation of the referenced study. Author defined 'RateData' = "QFFD" Slip rate bin lower bound, assigned to the fault in the QFFD. Author defined 'RateData' = "rate balanced" Explanation of the fault rates balanced to yield the assigned rate. Author defined 'RateData' = "nominal assigned value" The fault section rate is not explicitly known but assigned to match the lower QFFD rate bin that the authors deemed suitable based on fault expression. Author defined DipDeg Fault dip in degrees from horizontal. If dip is based on published observations (i.e., not assumed based on slip sense), the reference is cited in the 'DipRef' field of this table. Author defined 5 90 Degrees DipDir Direction of fault dip. Author defined N north Author defined NE northeast Author defined E east Author defined SE southeast Author defined S south Author defined SW southwest Author defined W west Author defined NW northwest Author defined V vertical Author defined DipRef Source study citation for fault dip, or basis for dip assumption (e.g., "assumed based on slip sense (reverse)"). Author defined Source study citation for fault dip, or basis for dip assumption (e.g., "assumed based on slip sense (reverse)"). LowDepth Lower structural depth of fault in kilometers. The default value is 0 for unknown lower fault depths. References cited for reported lower depth values are listed in the 'DepthRef' field of this table. Author defined 10 35 DepthRef Reference cited for 'LowDepth' field'. Default LowDepth value of 0 km corresponds to faults of unknown lower depth. Author defined Reference cited or nominal default assignment for "LowDepth" field entry. U.S. Geological Survey USGS ScienceBase Team Mailing and Physical

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Denver Colorado 80225 USA 1-888-275-8747 sciencebase@usgs.gov The U.S. Geological Survey, Alaska Science Center is the authoritative source of these data, distributed by ScienceBase (a USGS Trusted Digital Repository). Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data for other purposes or on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. SHP, GeoJson, KML, CSV Vector geospatial data in SHP, GeoJSON, and KML formats; tabular data in CSV format; FGDC metadata in XML and HTML formats. https://doi.org/10.5066/P97NRR0F None 20250609 U.S. Geological Survey, Alaska Science Center Mailing and Physical

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Anchorage Alaska 99508 USA 907-786-7000 gs-ak_asc_datamanagers@usgs.gov FGDC Content Standard for Digital Geospatial Metadata (CSDGM) FGDC-STD-001-1998