Christopher F. Waythomas Thomas P. Miller Margaret T. Mangan Frank A. Trusdell Andrew T. Calvert Katie Sullivan 2025 vector digital data Reston, VA U.S. Geological Survey https://doi.org/10.5066/P1HUP9CA Thomas P. Miller Christopher F. Waythomas Margaret T. Mangan Frank A. Trusdell Andrew T. Calvert 2025 publication Scientific Investigations Map SIM 3519 Reston, VA U.S. Geological Survey https://doi.org/10.3133/sim3519 The Emmons Lake volcanic center is a spatially clustered group of stratovolcanoes and calderas on the Alaska Peninsula near Cold Bay, Alaska. The volcanic center is characterized by several ice- and snow-clad stratovolcanoes located within and along the margins of a nested-caldera complex that includes Emmons Lake. A shield-like ancestral edifice (ancestral Mount Emmons) is truncated by the caldera complex and forms a broad volcanic platform around the center. The main stratovolcanoes of the Emmons Lake volcanic center (from northeast to southwest) are Pavlof Sister, Pavlof Volcano, Little Pavlof, Double Crater, Mount Hague, and Mount Emmons. Pavlof Volcano, in the northeastern part of the Emmons Lake volcanic center, is one of the most historically (that is, the past about 300 years) active volcanoes in Alaska, and eruptions from Pavlof Volcano pose the greatest hazards to the region. Lava flows, volcanic breccia, and fluvial volcaniclastic rocks of the Emmons Lake volcanic center, which are as old as late Miocene, overlie continental and marine sedimentary rocks of chiefly Late Jurassic to early Tertiary age. The Emmons Lake volcanic center was affected multiple times by Quaternary glaciation, and glaciation has played a key role in shaping the present-day landscape. Much of the eruptive history of the Emmons Lake volcanic center has involved interactions with glacier ice. Thus, a brief review of the Quaternary glacial history of the area is provided to establish the physical context for Emmons Lake volcanic center eruptive activity. The purpose of this report is to describe the geology and eruptive history of the Emmons Lake volcanic center. The main contribution of this report to the multiyear study of the volcanic geology of the area is its 1:100,000-scale geologic map and cross section of the volcanic center. The spatial database contains detailed information about geologic-unit compositions, faults, and contacts. Also included in this report are photographs and figures illustrating key geologic relations, thin-section photographs and brief descriptions, and tables of radiocarbon ages and argon-argon and potassium-argon ages and data. Available in two associated data releases are thin-section data and major- and trace-element geochemical analyses of major rock units. This database contains file geodatabase feature classes describing geologic lines and polygons, faults, caldera boundaries, geochronology, and rock chemistry. This metadata file was written to provide an overview description of the complete database. Any shapefiles derived from the geodatabase may have abbreviated or shortened field names. The data release contains a geodatabase that contains one feature dataset, GeologicMap. The feature dataset contains the feature classes that store the geologic data. In addition to the feature dataset, this database contains four tables. Below is an attribute overview for the features found in the feature classes and tables. Detailed metadata files can be found associated with each feature class. There are three line feature classes: ContactsAndFaults, CartographicLines, and GeologicLines. The ContactsAndFaults feature class contains the locations of the geologic contacts, faults, dikes, scarps, and water boundaries. The Type field contains the designations for each, and the IsConcealed, ExistenceConfidence, IdentityConfidence, and LocationConfidence fields contain whether the object is concealed, how well the author can recognize the line, and how well the author can locate the line. The CartographicLines feature class contains non-geologic lines used on the cartographic layout, for example leaders and cross section locations. The GeologicLines feature class contains the locations of synclines, anticlines, fold hinges, and caldera boundaries. These feature classes also contain other fields specified by the GeMS database schema. These feature classes also contain other fields specified by the GeMS database schema. There is one polygon feature class: MapUnitPolys. The MapUnitPolys feature class contains the boundaries for geologic units. Geologic unit symbols for each polygon are stored in the MapUnit field, and the IdentityConfidence field describes how well the author can identify the map unit at this location. The MapUnit field can be used as the primary key to join or relate the MapUnitPolys feature class to the DescriptionsOfMapUnits table using the MapUnit field in this table as the foreign key for access to geologic unit symbols, full geologic unit names and ages, and complete unit descriptions. This feature class also contains other fields specified by the GeMS database schema. There are two point feature classes: GeochronPoints and VolcanicPoints. The GeochronPoints feature class contains the locations of the geochronology measurements taken. The author's preferred age is listed in the PreferredAge field with PreferredAgeError. The VolcanicPoints feature class contains the locations of vents and fumaroles. These feature classes also contain other fields specified by the GeMS database schema. There are seven annotation feature classes: CartographicLinesAnno, ConeAnno, GeochronPointsAnno, GeogAnno, GeologicLinesAnno, HydroAnno, and MapUnitPolyAnno. These feature classes contain cartographic elements for labeling features such as map unit polygons, place names, fault names, and river names. Each feature has a spatial location as well as all the label text and font style information to display the cartographic text. The text to label the feature is stored in the Text String field. These fields are Esri managed and defined as map text is updated in the software. These feature classes are not specified by the GeMS database schema. The database also contains four tables: DataSources, DescriptionOfMapUnits, GeoMaterialDict, and Glossary. The DataSources table contains the references used in the creation of this map. The DataSourcesID is the foreign key to the DataSources_ID field in all other tables. The DescriptionOfMapUnits table contains the geologic unit symbols, full geologic unit names and ages, and complete unit description for each of the geologic units on the map in the MapUnit, Name, FullName, and Age, and Description fields. The GeoMaterialDict table contains the standard definitions for the geomaterials found in the DescriptionOfMapUnits table. This is a standard default GeMS table. The Glossary table provides definitions in the Definition field for many of the terms used in the database. These tables also contain other fields specified by the GeMS database schema. 19990817 20050807 ground condition Complete None planned -162.3526 -161.7454 55.5083 55.2019 ISO 19115 Topic Category geoscientificInformation USGS Thesaurus geologic maps geology volcanology glaciation hazards volcanic rocks geologic history Lithologic classification of geologic map units Tuff Andesite Basalt Dacite Rhyodacite Rhyolite Alexandria Digital Library Feature Type Thesaurus volcanic features USGS Metadata Identifier USGS:a320f1d8-3454-45f9-8c9f-39b78555ebfe None Mount Emmons Emmons Lake Pavlof Volcano Alaska Peninsula Common geographic areas Alaska United States Alaska Peninsula National Wildlife Refuge No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons Zero v1.0 Universal (CC0-1.0) public domain dedication and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Christopher F. Waythomas USGS - ALASKA REGION Research Hydrologist mailing and physical

Glenn Olds Hall, Alaska Pacific University, Alaska

Anchorage AK 99508 907-786-7122 cwaythomas@usgs.gov T.P. Miller, C.F. Waythomas, M.T. Mangan, F.A. Trusdell, A.T. Calvert, and C.J. Nye, 1999–2004; minor revisions, 2005–2017. Reconnaissance sampling and mapping by T.P. Miller, D.H. Richter, and M.E. Yount, 1986–1991. Potassium-argon geochronology by M. Lanphere from samples collected in 1974. Argon-argon geochronology by P. Layer and A.T. Calvert from samples collected in 1999–2004. GIS database and digital cartography by E. Thoms and J. McIntire. Edited by Taryn A. Lindquist; digital cartographic production by Katie Sullivan. Manuscript approved for publication January 26, 2024 Windows 11 Enterprise, Version: 23H2, OS build: 22631.6199, Windows Feature Experience Pack 1000.22700.1108.0, ArcGIS Pro 3.5.2 No formal attribute accuracy tests were conducted. Polygon and arc (chain-node) topology present in appropriate feature classes. Other feature classes are point, annotation or raster and do not require topologic relationships. Data review shows that values fall within expected ranges and data metadata adequately describes data. The data set is intended to describe completely the igneous and volcanic products, and volcanic vent locations at 1:63,360 scale. Geological information appropriately mapped at larger scale has been omitted. Data set is considered complete for the information presented, as described in the abstract. The position of each feature in the database is derived from a USGS 1:63,360 topographic base map. The positional accuracy of each feature is indicated quantitatively within the LocationConfidenceMeters field in the attribute table. In general, features in the database are well located, or within 30 m. A formal accuracy assessment of the vertical positional information in the data set has either not been conducted, or is not applicable. The original geodatabase and associated GIS files were missing; therefore, a new geodatabase was reconstructed from the Adobe Illustrator map document using Avenza MaPublisher, a geospatial and cartographic software integrated with Illustrator. Because the map data were displayed on a historic topographic base that did not align with modern coordinates, updated spatial reference information was required. The historic topographic maps were imported into ArcGIS Pro, and an updated latitude and longitude graticule was generated and overlaid to establish current coordinate control. This graticule was then transferred to the Illustrator document and aligned to the topographic base for spatial consistency. MaPublisher was used to georeferenced the map using control points derived from the updated coordinate grid. Following successful georeferencing, individual Illustrator layers were exported as ESRI shapefiles and organized by feature type (e.g., contacts, unit polygons). An empty file geodatabase was created in ArcGIS Pro, and then shapefiles were exported into feature classes in the newly created geodatabase. Geologic and geographic annotation feature classes were then created and modified throughout the production process. The final geodatabase was subsequently prepared for compliance with the Geologic Map Schema (GeMS) through correction of topology errors, creation of required fields and tables, population of mandatory attributes, and execution of GeMS validation tools to identify and resolve remaining schema inconsistencies. 2025 Universal Transverse Mercator 3 0.9996 -165.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meters North_American_Datum_1927 Clarke 1866 6378206.4 294.978698213898 This database contains file geodatabase feature classes describing geologic lines and polygons, faults, caldera boundaries, geochronology, and rock chemistry. This metadata file was written to provide an overview description of the complete database. Any shapefiles derived from the geodatabase may have abbreviated or shortened field names. The data release contains a geodatabase that contains one feature dataset, GeologicMap. The feature dataset contains the feature classes that store the geologic data. In addition to the feature dataset, this database contains four tables. Below is an attribute overview for the features found in the feature classes and tables. Detailed metadata files can be found associated with each feature class. There are three line feature classes: ContactsAndFaults, CartographicLines, and GeologicLines. The ContactsAndFaults feature class contains the locations of the geologic contacts, faults, dikes, scarps, and water boundaries. The Type field contains the designations for each, and the IsConcealed, ExistenceConfidence, IdentityConfidence, and LocationConfidence fields contain whether the object is concealed, how well the author can recognize the line, and how well the author can locate the line. The CartographicLines feature class contains non-geologic lines used on the cartographic layout, for example leaders and cross section locations. The GeologicLines feature class contains the locations of synclines, anticlines, fold hinges, and caldera boundaries. These feature classes also contain other fields specified by the GeMS database schema. These feature classes also contain other fields specified by the GeMS database schema. There is one polygon feature class: MapUnitPolys. The MapUnitPolys feature class contains the boundaries for geologic units. Geologic unit symbols for each polygon are stored in the MapUnit field, and the IdentityConfidence field describes how well the author can identify the map unit at this location. The MapUnit field can be used as the primary key to join or relate the MapUnitPolys feature class to the DescriptionsOfMapUnits table using the MapUnit field in this table as the foreign key for access to geologic unit symbols, full geologic unit names and ages, and complete unit descriptions. This feature class also contains other fields specified by the GeMS database schema. There are two point feature classes: GeochronPoints and VolcanicPoints. The GeochronPoints feature class contains the locations of the geochronology measurements taken. The author's preferred age is listed in the PreferredAge field with PreferredAgeError. The VolcanicPoints feature class contains the locations of vents and fumaroles. These feature classes also contain other fields specified by the GeMS database schema. There are seven annotation feature classes: CartographicLinesAnno, ConeAnno, GeochronPointsAnno, GeogAnno, GeologicLinesAnno, HydroAnno, and MapUnitPolyAnno. These feature classes contain cartographic elements for labeling features such as map unit polygons, place names, fault names, and river names. Each feature has a spatial location as well as all the label text and font style information to display the cartographic text. The text to label the feature is stored in the Text String field. These fields are Esri managed and defined as map text is updated in the software. These feature classes are not specified by the GeMS database schema. The database also contains four tables: DataSources, DescriptionOfMapUnits, GeoMaterialDict, and Glossary. The DataSources table contains the references used in the creation of this map. The DataSourcesID is the foreign key to the DataSources_ID field in all other tables. The DescriptionOfMapUnits table contains the geologic unit symbols, full geologic unit names and ages, and complete unit description for each of the geologic units on the map in the MapUnit, Name, FullName, and Age, and Description fields. The GeoMaterialDict table contains the standard definitions for the geomaterials found in the DescriptionOfMapUnits table. This is a standard default GeMS table. The Glossary table provides definitions in the Definition field for many of the terms used in the database. These tables also contain other fields specified by the GeMS database schema. The entity and attribute information were generated by the individual and/or agency identified as the originator of the data set. Please review the rest of the metadata record for additional details and information. U.S. Geological Survey NGMDB mailing address

12201 Sunrise Valley Drive

MS 908

Reston VA 20192 USA N/A ngmdb@usgs.gov 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 (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P1HUP9CA None 20251201 Christopher F. Waythomas USGS - ALASKA REGION Research Hydrologist mailing and physical

Glenn Olds Hall, Alaska Pacific University, Alaska

Anchorage AK 99508 907-786-7122 cwaythomas@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998