DOI: 10.5066/p13nfglt
title: Quaternary fault mapping of the Zapata and Blanca sections of the Sangre de Cristo fault zone from high-resolution 3DEP topography

description: This data release contains a dataset that depicts fault scarps along the Zapata and Blanca sections of the Sangre de Cristo fault zone located in the San Luis basin of southern Colorado. The Zapata and Blanca sections extend from the Great Sand Dunes National Park and Preserve to the Blanca Peak massif and are differentiated by a sharp change in fault zone orientation from north-south to east-west. The fault scarps are the result of Quaternary tectonic extension causing surface rupturing earthquakes estimated to have occurred most recently 8-12 ka with probable Mw 6-7 (Ruleman & Machette, 2007). The dataset represents detailed mapping of probable fault surface rupture on high-resolution (1m/pix) topographic data from USGS 3DEP (U.S. Geological Survey, 2012; U.S. Geological Survey, 2021) mapped at 1:1400 scale. The mapping has been validated with GPS surveys at select locations along the fault zone. Primarily, mapping was conducted between September 2022 and December 2022 with subsequent updates and corrections. The data has undergone peer review but remains subject to revision as more information becomes available. The dataset is provided in shapefile KML, and geoJSON formats.

Explanation of Data:

Fault Lines
The dataset consists of detailed fault mapping from high resolution USGS 3DEP lidar-derived digital elevation models (1-meter/pix resolution DEMs) and computed topographic derivatives (shaded relief, slope, and curvature). Mapping was performed at 1:1400 scale. Lines included in the dataset demarcate fault scarps and tectonic lineations. Mapping is based on geomorphic indicators visible in the topographic data with field validation from GPS surveys in select locations. The attributes of the linework dataset describe the mapped faults: The ‘Symbol’ field denotes the Federal Geographic Data Committee code for the line. The ‘type’ field describes the specific feature mapped (normal fault, lineation, etc.). The ‘id_confid’ field provides a confidence ranking for whether the feature is a fault (high, medium, or low) and the ‘loc_confid’ field describes confidence in the fault’s positional accuracy at the surface. The ‘notes’ attribute provides a more detailed description of the mapped feature, such as the scarp-face direction or degree of geomorphic and/or anthropogenic modification. The linework has been peer reviewed for both geologic identification and mapping accuracy.

References: 
Ruleman, C. and Machette, M., 2007, An Overview of the Sangre de Cristo Fault System and New Insights to Interactions Between Quaternary Faults in the Northern Rio Grande Rift in Rocky Mountain Section Friends of the Pleistocene Field Trip – Quaternary geology of the San Luis Basin of Colorado and New Mexico, September 7-9, 2007: U.S. Geological Survey Open-File Report 07-1193, 197 p.
 
U.S. Geological Survey, 2021, 3D Elevation Program 1-Meter Resolution Digital Elevation Model CO_SanLuisJuanMiguel_2020_D20: accessed 2022-12-18 at https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/CO_SanLuisJuanMiguel_2020_D20/CO_SanLuisJuanMiguel_4_2020.
 
U.S. Geological Survey, 2012, 3D Elevation Program 1-Meter Resolution Digital Elevation Model CO-San-Luis-Valley 2011: Distributed by OpenTopography, accessed 2022-12-18 at https://portal.opentopography.org/usgsDataset?dsid=CO_San-Luis-Valley_2011.