Data for: Kroll and Cochran, 2024, Cyclic Injection Leads to Larger and More Frequent Induced Earthquakes Under Volume-Controlled Conditions, Seismoloigcal Research Letters

Supplemental Material for: “Cyclic Injection Lead to Larger and More Frequent Induced Earthquakes” Seismological Research Letters, submitted 2023.

Kayla A. Kroll and Elizabeth S. Cochran

These are the 2000 unique synthetic seismicity catalogs that were produced for the work to understand the impact of constant rate versus cyclically varying injection rates on seismicity.

These catalogs were developed by considering the following:

·      Two injection histories

o   Constant rate injection (hereinafter referred to as “constant”) of 0.008 m^2/s for 70 years

o   Fluctuating injection (hereinafter referred to as “cyclic”) at a rate of 0.014 m^2/s for 10 year intervals

§  Injection rate of 0.014 m^2/s applied between 0-10 years, 20-30 years, 40-50 years, 60-70 years

§   Injection rate of 0.00 m^2/s applied between 10-20 years, 30-40 years, 50-60 years, 70+ years

·      Two values of the average pre-existing shear stress (hereinafter referred to as “initTau”)

o   initTau = 16 MPa

o   initTau = 17 MPa

·      500 unique realizations of the pattern of the pre-existing shear stress. These patterns are generated using the von Karman auto-correlation function which can be reconstructed with 4 parameters: Hurst exponent (H), correlation length (axay), standard deviation of the amplitude of the heterogeneity (Asd), and the seed value used in the random number generator. The algorithm PSUADE (https://computing.llnl.gov/projects/psuade) was used in Design of Experiments manner to determine 100 unique combinations of the independent/physical variables (H, axay, and Asd). These combinations were then repeated over 5 values of the categorical parameter (the seed term). We use a quasi Monte Carlo method for deriving the sampling combinations with draws from uniform probability distributions in the following ranges for each parameter:

o   0 < H < 1

o   30m < axay < 10000m

o   1 MPa < Asd < 5 MPa (~0.3initTau)

·      The name of each catalog in this repository is coded to indicate which injection strategy was applied (e.g. Cyclic or fluctuating), the value of the average initial pre-existing shear stress (e.g. initTau), and the statistical properties of the von Karman distribution (e.g. H, axay, Asd, seed).