Digital database of the geologic map of the middle east rift geothermal subzone, Kilauea Volcano, Hawai'i By Michael H. Zoeller, Frank A. Trusdell, and Richard B. Moore U.S. Geological Survey (USGS) Data Series 1111 2019 WEB ACCESS This report and any updates to it are available at https://doi.org/10.3133/ds1111. INTRODUCTION This database release contains all the information used to produce Geologic Investigations Series map I-2614 (https://pubs.usgs.gov/imap/2614/). The main component of this digital release is a geodatabase prepared using ArcGIS, but Esri shapefiles are included as well. ABSTRACT Kilauea is an active shield volcano in the southeastern part of the Island of Hawai'i. The middle East Rift Zone (MERZ) map includes about 27 square kilometers of the MERZ and shows the distribution of the products of 34 separate eruptions during late Holocene time. Lava flows erupted during 1983-86 have reached the mapped area. The subaerial part of the MERZ is 3-4 km wide and about 18 km long. It is a constructional ridge, 50-150 m above the adjoining terrain, marked by low spatter ramparts and cones as high as 60 m. Lava typically flowed either northeast or southeast, depending on vent location relative to the topographic crest of the rift zone. The MERZ receives more than 100 inches of rainfall annually and is covered by tropical rain forest. Vegetation begins to grow on lava a few months after its eruption. Relative heights of trees can be a guide to relative ages of underlying lava flows, but proximity to faults, presence of easily weathered cinders, and human activity also affect the rate of growth. The rocks have been grouped into five basic age groups. The framework for the ages assigned is provided by eight radiocarbon ages from nearby mapping by the authors and a single date from within this investigation area. The numerical ages are supplemented by observations of stratigraphic relations, degree of weathering, soil development, and vegetative cover. ACKNOWLEDGMENTS The authors sincerely thank Joel Robinson (USGS, California Volcano Observatory) and Joe Bard (USGS, Cascades Volcano Observatory) for their reviews of this report, and Jan Zigler (USGS, Menlo Park Publishing Science Center) for her proofreading and assistance in the publication process. Their combined efforts provided valuable input, greatly improving the usability of the geospatial data and the readability of the metadata. The authors also extend their appreciation to the Hawaii Department of Land and Natural Resources, the Office of Hawaiian Affairs, and Hawai'i Volcanoes National Park for facilitating field operations and implementing safety measures, among other logistical support roles. Their efforts make it possible for the USGS to conduct remote field operations safely and with respect for the rich cultural and environmental resources on the Island of Hawai'i. FILES AND FOLDERS KIL_MiddleERZ.gdb: Esri file geodatabase for the Geologic map of the middle east rift geothermal subzone, Kilauea Volcano, Hawai'i. KIL_MiddleERZ.mxd: Esri ArcMap document displaying the geodatabase data. Shapefiles: Folder containing Esri shapefile and dBASE versions of the feature classes and non-spatial tables, respectively, in the KIL_MiddleERZ.gdb geodatabase. The "Open" shapefiles are direct exports from the feature classes and non-spatial tables, and the "Simple" shapefiles are more easily readable versions of the feature classes. Each folder also contains a GeoTIFF version of the background digital raster graphic in the Geologic map of the middle east rift geothermal subzone, Kilauea Volcano, Hawai'i. Metadata: FGDC metadata text files describing the feature classes in the KIL_MiddleERZ.gdb Esri file geodatabase, the corresponding Esri shapefiles, and accompanying GeoTIFFs. Symbology: Folder containing layer files to symbolize the shapefiles, and an Esri style file with symbols for all features. ReadMe.txt: Overview of the data folder - this file. PRINTED COPY AVAILABLE Visit http://store.usgs.gov to order Geologic Investigations Series map I-2614 and other USGS information products. SUGGESTED CITATION Zoeller, M.H., Trusdell, F.A., and Moore, R.B., 2019, Digital database of the geologic map of the middle east rift geothermal subzone, Kilauea Volcano, Hawai'i: U.S. Geological Survey Data Series 1111, scale 1:24,000. DISCLAIMERS All trademarks and trade names are the property of their respective owners.