Project Grant G25AP00315

PROJECT TITLE: QUATERNARY SLIP RATES AND SURFACE GEOMETRY OF THE EAST GALLATIN-REESE CREEK FAULT SYSTEM, YELLOWSTONE NATIONAL PARK: COLLABORATIVE RESEARCH WITH MONTANA TECHNOLOGICAL UNIVERSITY AND WYOMING STATE GEOLOGICAL SURVEYPROJECT PERIOD: 8 1 2025 THROUGH 7 31 2026AWARD PURPOSE: UNDERSTANDING THE EARTHQUAKE HAZARD POSED BY AN ACTIVE FAULT RELIES ON FUNDAMENTAL KNOWLEDGE OF THE FAULTS GEOMETRY AND SLIP HISTORY. THIS STUDY WILL INVESTIGATE THE GEOMETRY AND SLIP RATE OF THE EAST GALLATIN-REESE CREEK FAULT SYSTEMA 40-KM-LONG, QUATERNARY-ACTIVE, EAST-DIPPING NORMAL FAULT SYSTEM IN NORTHWEST YELLOWSTONE NATIONAL PARKTO BETTER UNDERSTAND ITS SEISMIC HAZARD. THE RECIPIENT WILL MAP FAULT SCARPS, MEASURE FAULT SCARP TOPOGRAPHIC PROFILES, AND DATE FAULT-DISPLACED DEPOSITS USING COSMOGENIC RADIONUCLIDE EXPOSURE DATING. RESULTS WILL INFORM TARGETED QUESTIONS ABOUT FAULT GEOMETRY AND EXTENT, AND THE RATE AND VARIABILITY OF POST-GLACIAL FAULT SLIP. ACTIVITIES TO BE PERFORMED: (1) MAP FAULT SCARPS ALONG THE TRACE OF THE EAST GALLATIN-REESE CREEK FAULT SYSTEM USING LIGHT DETECTION AND RANGING DIGITAL ELEVATION MODELS AND FIELD VERIFICATION (2) USE COSMOGENIC RADIONUCLIDE EXPOSURE DATING TO QUANTIFY THE AGE OF GLACIAL DEPOSITS AND GEOMORPHIC SURFACES OFFSET ACROSS SCARPS OF THE EAST GALLATIN-REESE CREEK FAULT SYSTEM (3) MEASURE FAULT SCARP TOPOGRAPHIC PROFILES USING LIGHT DETECTION AND RANGING DIGITAL ELEVATION MODELS TO QUANTIFY VERTICAL SEPARATION OF GEOMORPHIC SURFACES ALONG THE EAST GALLATIN-REESE CREEK FAULT SYSTEM.DELIVERABLES AND EXPECTED OUTCOMES: PROJECT DELIVERABLES WILL BE: (1) DIGITAL SPATIAL DATA OF MAPPED FAULT SCARPS, COSMOGENIC RADIONUCLIDE SAMPLE LOCATIONS, AND SCARP TOPOGRAPHIC PROFILE LOCATIONSALL OF WHICH ARE INTENDED FOR USE IN A GEOGRAPHIC INFORMATION SYSTEM (2) TABULAR DATA OF COSMOGENIC RADIONUCLIDE ANALYTICAL RESULTS, SCARP VERTICAL SURFACE SEPARATION CALCULATIONS, AND FAULT SLIP RATE CALCULATIONSALL OF WHICH ARE INTENDED FOR USE IN A SPREADSHEET PROGRAM (3) MAP PLATE AT A SCALE OF 1:24,000 OR GREATER DISPLAYING THE SURFACE TRACE OF THE EAST GALLATIN-REESE CREEK FAULT SYSTEM, COSMOGENIC RADIONUCLIDE SAMPLE LOCATIONS, AND RELEVANT GEOMORPHIC FEATURES (4) REPORT DETAILING THE PROJECT FINDINGS. DELIVERABLES 1 AND 2 WILL BE PUBLISHED AS WYOMING STATE GEOLOGICAL SURVEY DATA RELEASES DELIVERABLES 3 AND 4 WILL BE PUBLISHED AS JOINT WYOMING STATE GEOLOGICAL SURVEY MONTANA BUREAU OF MINES AND GEOLOGY PEER-REVIEWED PUBLICATIONS CONSISTING OF A STANDALONE GEOLOGIC MAP AND A TECHNICAL REPORT. ALL DELIVERABLES WILL BE PUBLICLY AVAILABLE AS FREE DIGITAL FILE DOWNLOADS. THE EXPECTED OUTCOMES OF THIS WORK ARE TO GENERATE SPATIAL DATA ON THE SURFACE GEOMETRY AND QUANTITATIVE DATA ON THE LATE QUATERNARY SLIP RATE OF THE EAST GALLATIN-REESE CREEK FAULT SYSTEM. FAULT GEOMETRY AND SLIP RATE DATA ARE THE PRIMARY COMPONENTS OF EARTHQUAKE GEOLOGY DATASETS THAT ARE INPUTS TO THE NATIONAL SEISMIC HAZARD MODEL, YET THERE ARE NO PREVIOUS STUDIES THAT HAVE EXPRESSLY DETERMINED THESE PARAMETERS FOR THE EAST GALLATIN-REESE CREEK FAULT SYSTEM. OUTCOMES FROM THIS WORK WILL THUS HELP REFINE THE PROBABILISTIC GROUND MOTION MAPS, HAZARD CURVES, AND OTHER IMPACTFUL SEISMIC HAZARD PRODUCTS FOR SUBSEQUENT UPDATES TO THE NATIONAL SEISMIC HAZARD MODEL IN NORTHWEST WYOMING AND SOUTHWEST MONTANA.INTENDED BENEFICIARIES: FAULT GEOMETRY AND SLIP RATE RESULTS ARE INTENDED TO BE DIRECT INPUTS INTO FAULT SECTION AND EARTHQUAKE GEOLOGY INFORMATION DATABASES THAT ARE COMPILED BY THE U.S. GEOLOGICAL SURVEY FOR PERIODIC UPDATES TO THE NATIONAL SEISMIC HAZARD MODEL. THE PROJECT DELIVERABLES ARE ALSO INTENDED FOR USE BY LOCAL GOVERNMENTS AND LAND MANAGEMENT AGENCIES, INCLUDING YELLOWSTONE NATIONAL PARK, TO INFORM GEOLOGIC HAZARD ASSESSMENTS THAT CAN BE USED TO MITIGATE EARTHQUAKE RISK TO RESIDENTS, VISITORS, AND INFRASTRUCTURE.SUBRECIPIENT ACTIVITIES: N A