Johanna M. Nevitt Tamara N. Jeppson Roger Bilham Diane E. Moore David A. Lockner Dawn C. S. Ruth Efe T. Ayruk 20260213 tabular digital data https://doi.org/10.5066/P13PIFJR Johanna M. Nevitt Tamara N. Jeppson Roger Bilham Diane E. Moore David A. Lockner William D. Barnhart Ziyadin Cakir Efe T. Ayruk Benjamin A. Brooks Dawn C. S. Ruth Nima Ekhtari Francisco G. Gomez Jonathan R. Weiss Sarah E. Minson Semih Ergintav Ugur Dogan Seda Ozarpaci Nadine G. Reitman Ruth A. Harris 20260129 tabular digital data Mineral assemblages frictional properties, and deformation mechanisms were investigated in samples collected from an outcrop exposure of the Pütürge segment of the East Anatolian Fault Zone, Turkey (Türkiye). X-ray powder diffraction (XRD) analysis was performed on five samples to determine the minerals present. Triaxial shearing experiments were conducted at the USGS Rock Physics Laboratory in Menlo Park, California (now Moffett Field, California) to determine the coefficient of friction and the friction rate parameter (a-b) under the following conditions: room temperature (21C) and 10 MPa effective normal stress; 100C and 36 MPa effective normal stress; 200C and 71 MPa effective normal stress. The rate parameter (a-b) was determined using RSFit3000 (Skarbek and Savage, 2019). Deformation microstructures of the experimental samples were examined using energy dispersive X-ray spectroscopy at the USGS Moffett Field Ebeams Facility, California. The data were collected to investigate the mineralogical and frictional properties of the Pütürge segment of the East Anatolian Fault Zone, Turkey (Türkiye). Samples were collected from a single outcrop exposure on the Pütürge segment of the East Anatolian Fault Zone, Turkey (Türkiye). Geographic coordinates are provided for sample provenance only; the data are laboratory measurements and images and do not constitute a spatial dataset. 20230424 20251115 Time range of laboratory experiments and analysis Complete None planned 38.5071 39.3228 38.4837 38.0351 ISO 19115 Topic Category biota None earthquake rate state friction creep fault USGS Thesaurus earthquakes USGS Metadata Identifier USGS:6972c61cd4be024aa5bde17f None Turkey East Anatolian Fault Puturge None. Please see 'Distribution Info' for details. None. Users are advised to read the data set's metadata thoroughly to understand appropriate use and data limitations. Johanna M. Nevitt U.S. Geological Survey Mailing

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Moffett Field CA 94035 USA 6504392461 Attribute values represent laboratory measurements and derived quantities obtained using established analytical procedures. X-ray diffraction data were collected under controlled instrument settings and processed using standard methods. Triaxial experimental friction data were corrected for jacket shear resistance, seal friction, machine stiffness, and driving block offset prior to calculation of friction coefficients. SEM/EDS image pixel values represent measured electron counts or semi-quantitative apparent elemental concentration and are accompanied by acquisition parameter files documenting instrument configuration and processing. No independent quantitative assessment of measurement uncertainty is provided beyond the documented experimental procedures. Logical consistency of the dataset was evaluated through internal review of file structure, filenames, and data values. Filenames encode experiment identifiers and conditions consistently across data types. Derived quantities, such as friction coefficients and shear displacement, were calculated using documented equations. SEM/BSE and EDS image files are accompanied by acquisition metadata files that describe instrument settings for each image set. No automated consistency checks beyond these reviews were performed. The dataset includes all laboratory measurements, experimental results, and image data described in the associated publication. X-ray diffraction data are provided for all analyzed samples. Triaxial experimental friction data are provided for all experiments discussed in the manuscript. SEM/BSE and EDS image files are included for the documented experiments, along with corresponding acquisition parameter files. Samples were collected from an outcrop exposure (38.2049 N, 38.7872 E) of the Pütürge segment of the East Anatolian Fault Zone, Turkey in March 2023. X-RAY DIFFRACTION DATA X-ray diffraction (XRD) analysis was performed on packed powder samples to determine the minerals present. Data were collected at 40 kV voltage and 20 mA beam current, with the detector scanning from 2 deg to 70 deg in diffraction angle (2-theta) and measuring intensity with a sampling width of 0.01-deg 2-theta and at a sampling rate of 1-deg 2-theta per minute. The presence of swelling clays was tested in two samples (3B, 4) by placing them in a glycol bath for 2-3 days and re-running the analysis. XRD analysis was performed at the USGS in Menlo Park, California. TRIAXIAL FRICTION DATA Rate-stepping triaxial shearing experiments were conducted to measure the frictional properties. Samples were ground to <106 micrometers and assembled into a 2-mm-thick gouge layer along a 30 deg inclined sawcut between cylindrical driving blocks. Room temperature experiments used 25.4 mm-diameter Westerly granite and Berea sandstone block pairs in a latex jacket. Heated experiments used 19.1 mm-diameter Westerly granite blocks in a lead jacket. All samples were saturated with deionized water and pore pressure was maintained to prevent phase change at elevated temperature. To assess frictional rate dependence, each experiment included four velocity steps in which the axial displacement rate changed abruptly between 1 micrometer/s and 0.1 micrometer/s. Experiments were performed in April and May 2023 in the USGS Rock Physics Laboratory in Menlo Park, California. The data were corrected to account for the jacket shear resistance, seal friction, machine stiffness, and driving block offset. The friction coefficient is calculated as mu = (corrected shear stress) / (effective normal stress). Shear displacement along the inclined fault plane was calculated from the corrected axial displacement as D_shear = D_axial/cos(30 deg). ENERGY DISPERSIVE X-RAY SPECTROSCOPY (EDS) DATA Backscattered electron (BSE) images and energy dispersive x-ray spectroscopy (EDS) maps were collected using a Tescan Vega 3 scanning electron microscope (SEM) with two attached Oxford X-MaxN 150 mm2 energy dispersive spectrometers. Samples from Experiment Turkey 7 (Sample 3A, 100C, 36 MPa effective normal stress) and Experiment Turkey8 (Sample 3A, 200C, 71 MPa effective normal stress) were epoxied, cut in the slip direction orthogonal to the shear plane, polished to probe quality, and carbon coated. Data were collected in AZtec at 2048 resolution under vacuum with an accelerating voltage of 15 kV, a working distance of 15 mm, a process time of 4, and a pixel dwell time of 100 microseconds. Beam intensity was optimized to produce a dead time between 30-40%. QuantMap processing of all elements was performed, with pulse pile up correction, thresholding with 3.0 sigma level, with carbon deconvoluted, and results normalized. SEM-EDS analysis was performed in November 2025 at the USGS Ebeams Facility in Moffett Field, California. Acquisition details for Turkey7 EDS map in Fig. 5C Pixel Size: 0.07495 µm Image Width: 154μm Image Height: 154μm Magnification: 1607 x Acquisition details for Turkey7 EDS map in Fig. 5D: Pixel Size: 0.16388 µm Image Width: 336μm Image Height: 336μm Magnification: 735 x Acquisition details for Turkey8 EDS map in Fig. 5E: Pixel Size: 0.07340 µm Image Width: 150μm Image Height: 150μm Magnification: 1641 x Acquisition details for Turkey8 EDS map in Fig. 5F-I: Pixel Size: 0.02056 µm Image Width: 42.1μm Image Height: 42.1μm Magnification: 5860 x 20251115 XRD_Sample*.csv Comma Separated Value (CSV) file containing data. Producer defined 2 theta Diffraction Angle Producer defined 2.0 70.0 Intensity Intensity Producer defined 3.33333 8668.33 Experiment_Turkey*.csv Comma Separated Value (CSV) file containing data. Producer defined Time_s Time Producer defined 0 27100 s ShearDisplacement_mm Shear Displacement Producer defined -0.0914082242956268 10.290633463009 mm EffectiveNormalStress_MPa Effective Normal Stress Producer defined 9.977780000000001 10.081 MPa EffectiveFrictionCoefficient Effective Friction Coefficient Producer defined -0.0228273394502725 0.37019801977664396 FrictionRateParameter_Summary.csv Comma Separated Value (CSV) file containing data. Producer defined ExperimentName Experiment Name Producer defined Turkey4 Experiment on Sample 3B at room temperature, 10 MPa effective normal stress Producer defined Turkey5 Experiment on Sample 3A at room temperature, 10 MPa effective normal stress Producer defined Turkey7 Experiment on Sample 3A at 100C, 36 MPa effective normal stress Producer defined Turkey8 Experiment on Sample 3A at 200C 71 MPa effective normal stress Producer defined ShearDisplacement_mm Experimental shear displacement at the time of velocity step Producer defined 1.0332318 7.9940644 mm InitialVelocity_um_s Shear velocity at the start of the velocity step Producer defined 0.11002 1.1507 micrometer/s FinalVelocity_um_s Shear velocity at the end of the velocity step Producer defined 0.11305 1.159 micrometer/s a_minus_b Rate parameter a-b Producer defined -0.00138430077058123 0.00223039151412937 a_minus_b_Error 2-sigma error in a-b Producer defined 1.54321634222719e-05 0.000122069741747288 *_AcquisitionDetails.txt Text files with supplemental instrument metadata Producer defined Contents Acquisition resolution, pixel size, image dimensions, and SEM-EDS instrument and processing settings for the corresponding image set. Producer defined Acquisition resolution, pixel size, image dimensions, and SEM-EDS instrument and processing settings for the corresponding image set. Turkey_*.tiff Backscattered electron (BSE) images and Energy Dispersive X-Ray Spectroscopy (EDS) elemental maps Producer defined PixelValue Pixel values represent backscattered electron counts (BSE) and semi-quantitative apparent concentration (EDS) Producer defined Pixel values represent backscattered electron counts (BSE) and semi-quantitative apparent concentration (EDS) This data release contains laboratory measurements and imagery collected from natural and experimentally sheared fault gouge samples from the Pütürge segment of the East Anatolian Fault Zone, Turkey (Türkiye). The dataset includes X-ray diffraction (XRD) data, triaxial experimental friction data, friction rate parameters and errors derived from the experimental data, and scanning electron microscope (SEM) backscattered electron (BSE) images and energy-dispersive X-ray spectroscopy (EDS) elemental maps. Together, these data document mineralogical composition, frictional behavior, and deformation microstructures associated with fault gouge under controlled laboratory conditions. X-RAY DIFFRACTION DATA X-ray diffraction data are provided as comma-separated value (CSV) files (XRD_Sample*.csv), each corresponding to an individual sample collected from the outcrop. Files contain diffraction angle (2-theta) and measured intensity values from powder XRD. These data represent relative diffraction intensity as a function of angle and are used to identify mineral phases present in each sample. Detailed descriptions of sample preparation, instrument settings, and analytical procedures are provided in the metadata lineage section and the associated manuscript. TRIAXIAL FRICTION DATA Corrected triaxial experimental friction data are provided as CSV files (Experiment_Turkey*.csv). Each file contains time-series measurements from a single rate-stepping friction experiment, including elapsed time, shear displacement along the fault plane, effective normal stress, and the calculated coefficient of friction. Values represent laboratory measurements corrected for apparatus effects and are intended for analysis of frictional behavior under specified temperature, stress, and pore-pressure conditions. Experimental setup, correction procedures, and calculation methods are documented in the metadata lineage section and the primary manuscript. FRICTION RATE PARAMETER SUMMARY Friction rate parameter results are provided in FrictionRateParameter_Summary.csv. This file contains values of the rate-and-state friction parameter (a-b) and associated uncertainties derived from velocity step inversions of the experimental data. Each record corresponds to a specific experiment and velocity step. Details of the inversion methodology are provided by Skarbek and Savage (2019; https://doi.org/10.1130/GES02122.1). ENERGY DISPERSIVE X-RAY SPECTROSCOPY (EDS) DATA SEM backscattered electron images and EDS elemental maps are provided as individual TIFF files, organized by experiment and figure designation. BSE images represent backscattered electron counts, while EDS maps represent apparent elemental concentration at each pixel. For each image set, a corresponding text file (*_AcquisitionDetails.txt) documents acquisition parameters, pixel size, image dimensions, and processing settings. Detailed descriptions of sample preparation, SEM operating conditions, and EDS processing are provided in the metadata lineage section and the primary manuscript. Johanna M. Nevitt, Tamara N. Jeppson, Roger Bilham, Diane E. Moore, David A. Lockner, Dawn C. S. Ruth, and Efe T. Ayruk, 2026, Laboratory data for natural and experimental gouge samples from the Pütürge segment of the East Anatolian Fault Zone, Turkey (Türkiye): X-ray diffraction, triaxial shearing experiments, and energy dispersive X-ray spectroscopy: https://doi.org/10.5066/P13PIFJR. GS ScienceBase U.S. Geological Survey mailing address

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Denver CO 80225 United States 1-888-275-8747 sciencebase@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 on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P13PIFJR None 20260213 Johanna M. Nevitt Mailing

P.O. Box 158

Moffett Field CA 94035 650-439-2461 jnevitt@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998