The STRESSINVERSE code uses an iterative method to find the nodal planes most consistent with the stress field given fault frictional properties. STRESINVERSE inverts the strike, rake and dip from moment tensor solutions for the in-situ state of stress. The code iteratively solves for an optimal friction parameter in evaluating the fault instability to find optimal fault planes. Vavrycuk (2014) states that numerical tests show that inversion results are insensitive to the friction parameter, and it is sufficient to assign a reasonable value for all inversions. Vavrycuk, V., 2014. Iterative joint inversion for stress and fault orientations from focal mechanisms, Geophys. J. Int., 199, 69-77.

The link points to a website at NCEDC to download the full moment tensors inversion software The moment tensor analysis conducted in the current project is based on the full moment tensor model described in Minson and Dreger (2008). The software including source, examples and tutorial can be obtained from ftp://ncedc.org/outgoing/dreger (download file pasi-nov282012.tar.gz). Performance criteria, mathematics and test results are provided by Minson and Dreger (2008), Ford et al. (2008, 2009, 2010, 2012) and Saikia (1994). References: Ford, S., D. Dreger and W. Walter (2008). Source Characterization of the August 6, 2007 Crandall Canyon Mine Seismic Event in Central Utah, Seism. Res. Lett., 79, 637-644. Ford, S. R., D. S. Dreger and W. R. Walter (2009). Identifying isotropic events using a regional moment tensor inversion, J. Geophys. Res., 114, B01306, doi:10.1029/2008JB005743. Ford, S. R., D. S. Dreger and W. R. Walter (2010). Network sensitivity solutions for regional moment tensor inversions, Bull. Seism. Soc. Am., 100, p. 1962-1970. Ford, S. R., W. R. Walter, and D. S. Dreger (2012). Event discrimination using regional moment 665 tensors with teleseismic-P constraints, Bull. Seism. Soc. Am. 102, 867-872. Minson, S. and D. Dreger (2008), Stable Inversions for Complete Moment Tensors, Geophys. J. Int., 174, 585-592. Saikia, C.K. (1994), Modified Frequency-Wavenumber Algorithm for Regional Seismograms using Filons Quadrature: Modeling of Lg Waves in Eastern North America. Geophys. J. Int., 118, 142-158.

The link points to a website at NCEDC to download the full moment tensors inversion software The moment tensor analysis conducted in the current project is based on the full moment tensor model described in Minson and Dreger (2008). The software including source, examples and tutorial can be obtained from ftp://ncedc.org/outgoing/dreger (download file pasi-nov282012.tar.gz). Performance criteria, mathematics and test results are provided by Minson and Dreger (2008), Ford et al. (2008, 2009, 2010, 2012) and Saikia (1994). References: Ford, S., D. Dreger and W. Walter (2008). Source Characterization of the August 6, 2007 Crandall Canyon Mine Seismic Event in Central Utah, Seism. Res. Lett., 79, 637-644. Ford, S. R., D. S. Dreger and W. R. Walter (2009). Identifying isotropic events using a regional moment tensor inversion, J. Geophys. Res., 114, B01306, doi:10.1029/2008JB005743. Ford, S. R., D. S. Dreger and W. R. Walter (2010). Network sensitivity solutions for regional moment tensor inversions, Bull. Seism. Soc. Am., 100, p. 1962-1970. Ford, S. R., W. R. Walter, and D. S. Dreger (2012). Event discrimination using regional moment 665 tensors with teleseismic-P constraints, Bull. Seism. Soc. Am. 102, 867-872. Minson, S. and D. Dreger (2008), Stable Inversions for Complete Moment Tensors, Geophys. J. Int., 174, 585-592. Saikia, C.K. (1994), Modified Frequency-Wavenumber Algorithm for Regional Seismograms using Filons Quadrature: Modeling of Lg Waves in Eastern North America. Geophys. J. Int., 118, 142-158.

This submission contains 167 full moment tensor (MT) solutions for the seismicity observed two years prior and three years post start of injection activities. Also included are the azimuth and plunge angles for the three main stress directions sigma1, sigma 2 and sigma 3 at the Prati32 EGS demonstration site in the northwest Geysers geothermal reservoir. The data are divided into 15 time periods spanning a range of five years, including two years prior to start of injection until three years post start of injection activities.

This submission contains 167 full moment tensor (MT) solutions for the seismicity observed two years prior and three years post start of injection activities. Also included are the azimuth and plunge angles for the three main stress directions sigma1, sigma 2 and sigma 3 at the Prati32 EGS demonstration site in the northwest Geysers geothermal reservoir. The data are divided into 15 time periods spanning a range of five years, including two years prior to start of injection until three years post start of injection activities.

Included are experimental data recorded from shear experiments that specifically explore the link between fluid-injection rate and seismic moment resulting from shear reactivation of laboratory faults. Raw mechanical data from three experiments are included alongside corresponding MATLAB scripts that import and plot the data, as well as use it to calculate shear and normal stress. Experiments are performed on 2.5-3 inch long granitoid cores from the Utah FORGE EGS demonstration site, containing a single inclined fracture with small-scale roughness added to the fracture surface. The raw data included here were recorded from an aluminum triaxial pressure vessel (TEMCO) configured with three independent servo-controlled pumps, with distilled water used as the working fluid. The pumps control confining pressure, upstream pore pressure, and axial pressure, with each pump connected to a LabView interface to record applied pressures, cumulative injected water volumes, and pump flow rates. The downstream outlet from the fracture is closed to allow pressurization, which is measured by an external pressure transducer. A linear variable differential transformer (LVDT) attached to the axial piston measures axial displacement, from which we calculate shear displacement along the fracture. Additionally, P-wave transducers are used to record acoustic signatures, where acoustic emission events and maximum amplitudes are compared against seismic moment and shear slip velocity. Fluid injection rates range between 0.05 mL/min, 0.25 mL/min, and 0.75 mL/min for each experiment. Along-fault pressure distributions are progressively less uniform as injection rates increase, representing a switch from steady-state to transient conditions. Triggered shear displacement is used as a proxy for seismic moment and is indexed against cumulative injection volume and rate. Each experiment is performed under constant shear stress conditions, and the sample is fully saturated with DI water. Axial and confining stresses are applied to 3 MPa through pressure-stepping in 500 kPa increments. The pore pressure is held constant at 200 kPa prior to initiating the experiment, and initial axial displacement is recorded. The axial stress is then increased to initiate shear mobilization during the loading phase (run-in) until a peak steady state is achieved. The initial shear stress is reduced to approximately 80% of the peak shear stress by decreasing the axial stress, then held constant for the duration of each experiment.

This dataset contains experimental and acoustic data from shear reactivation tests that investigate the relationship between fluid-injection rate, pore pressure distribution, and seismic moment during laboratory fault slip. It includes raw mechanical data and acoustic emission recordings from fifteen experiments performed on 2.5-3 inch granitoid cores from the Utah FORGE enhanced geothermal systems (EGS) site. Each sample contains a single inclined fracture with small-scale surface roughness. Experiments were conducted in an aluminum triaxial pressure vessel (TEMCO) equipped with three independently servo-controlled pumps using distilled water as the working fluid. The pumps regulated confining, upstream pore, and axial pressures, with each connected to a LabView interface to record applied pressures, cumulative injected volumes, and flow rates. The downstream outlet was closed to allow pressurization, monitored by an external pressure transducer. Axial displacement was measured by a linear variable differential transformer (LVDT) attached to the axial piston and converted to shear displacement along the fracture. Acoustic emissions were recorded using P-wave transducers, with event timing, amplitude, and cumulative amplitude compared against seismic moment and shear slip velocity. Fluid injection rates of 0.05, 0.25, and 0.75 mL/min were applied under constant shear stress conditions, with both uniform and non-uniform along-fault pressure distributions. Samples were fully saturated with deionized water. Axial and confining stresses were increased to 3 MPa in 500 kPa increments, while pore pressure was held at 200 kPa prior to initiating shear mobilization. Axial stress was then increased to induce shear slip and subsequently reduced to approximately 60%, 80%, or 90% of the peak shear stress, depending on the experiment. The raw mechanical data files include time-series measurements of confining, pore, and axial pressures; pump volumes and flow rates; time (in hours:minutes:seconds); axial displacement (in millimeters); and downstream pressure (in psi).

A global, mosaiced (hybrid resolution) model of Vs30.

A global, mosaiced (hybrid resolution) model of Vs30.

Earthquake focal mechanisms and stress inversion results for the conterminous United States.