GSA Data Repository 8 Supplemental Information for Geospatial analysis of Oklahoma earthquakes ( - 6): Quantifying the limits of regional-scale earthquake mitigation measures Ryan M. Pollyea, Neda Mohammadi, John E. Taylor, and Martin C. Chapman Department of Geosciences, Virginia Polytechnic Institute and State University, 96 W. Campus Drive, Blacksburg, Virginia 6 School of Civil and Environmental Engineering, Georgia Institute of Technology, 79 Atlantic Drive NW, Atlanta, Georgia, DATA SOURCES The complete Oklahoma earthquake database was acquired by Internet download from OGS on June 7 (OGS, 7), and annual datasets were compiled between January and December 6 for complete annual earthquakes (M comp ), as well as magnitude.+ (M.+), M.+, and M.+ earthquakes. To assess catalog completeness for the M comp datasets, cumulative frequency-magnitude plots were created for each year of the study (Fig. DR). In doing so, the annual completeness threshold is identified on the basis of the Gutenberg-Richter Law (Gutenberg and Richter, 9) by () fitting a line through the decreasing portion of the distribution, and () determining the lowest earthquake magnitude without substantial deviation from the linear fit. Figure DR shows annual cumulative frequency-magnitude distribution plots, along with each linear fit and lower catalog completeness threshold.
Data for Class II injection well location and SWD volume in Oklahoma were acquired by Internet download for the calendar years - from the OCC website on 8 May 7 (OCC, 7a-e). Each data set was manually inspected to remove incomplete or duplicate records, as well as records without geo-location. The data were then filtered to include () wells within the study area, () wells completed within the combined Arbuckle-Simpson Group, and () wells with non-zero injection volume for a given year. For calendar year 6, well locations and injection volume for Class II wells were acquired by Internet download from the OCC website on 7 June 7 (OCC, 7f). This 6 data set includes weekly reports of daily injection volume for all Arbuckle disposal wells in the OCC Area of Interest, and, as a result, no filtering was required. In the context of geostatistical analysis, qualtitative analysis of the annual datasets indicates that monthly SWD volume is generally consistent for individual wells, and, as a result, the assumption of stationarity is accepted for annual cross semivariogram analysis. For 6, the annual distributions of total Class II SWD injection volume are presented in Figure DR, and the spatial distribution of Class II injection wells is illustrated in Figure DR.
FIGURES Catalog Log N =. -.8M M comp =. N = 97 Catalog Log N = 6.9 -.M M comp =. N =,96 Log N Log N 6 6 Catalog Catalog Log N =.8 -.M Log N = 6. -.M M comp =.7 M comp =. N = 97 N =, Log N 6 Catalog Log N =. -.M M comp =. N =, 6 6 Catalog Log N =.9 -.M M comp =. N =,9 6 Magnitude 6 Magnitude Figure DR. Cumulative frequency-magnitude distribution plots for each annual earthquake catalog compiled for this study. M comp is the lower threshold for catalog completeness determined on the basis of the Gutenberg-Richter Law.
6 o W o W 99 o W 97 o W 9 o W o W o W 99 o W 97 o W 9 o W Figure DR. Spatial distribution of annual earthquake catalogs (green circles) used for geospatial earthquake analysis.
. N = 6. N = 68. 6 8 6. 6 8 6. N = 78. N = 67. 6 8 6. 6 8 6. N = 7. 6 N = 8. 6 8 6. 6 8 6 Figure DR. Annual distribution of class II injection volume for wells within the project study study area (OCC, 7a-f).
6 - o W - o W -99 o W -97 o W -9 o W - o W - o W -99 o W -97 o W -9 o W Class II Injection Well Volume (M m ) <.6.6 -.6.6-6 6 -.79 >.79 Volume (M bbl) <.. -.99 -.99 - > Figure DR. Class II injection well location and SWD volume (OCC, 7a-f) within the study area. Gray shading denotes OCC Expanded Area of Interest for Triggered Earthquakes (OCC, 6) and dashed red box denotes study area.
REFERENCES CITED Gutenberg, B. and Richter, C.F., 9. Frequency of earthquakes in California: Bulletin of the Seismological Society of America, (), pp.8-88. OCC. 6. Media Advisory - Regional Earthquake Response Plan for Central Oklahoma and Expansion of Area of Interest: http://www.occeweb.com/news/6/-7-6advisory-aoi%c%volume%reduction.pdf, Accessed July 7. OCC. 7a. UIC Injection Volumes : http://www.occeweb.com/og/% A%UIC%volumes.xlsx, Accessed 8 May 7. OCC. 7b. UIC Injection Volumes : http://www.occeweb.com/og/% A%UIC%volumes.xlsx, Accessed 8 May 7. OCC. 7c. UIC Injection Volumes : http://www.occeweb.com/og/% A%UIC%volumes.xlsx, Accessed 8 May 7. OCC. 7d. UIC Injection Volumes : http://www.occeweb.com/og/% A%UIC%volumes.xlsx, Accessed 8 May 7. OCC. 7e. UIC Injection Volumes : http://www.occeweb.com/og/% A%UIC%volumes.xlsx, Accessed 8 May 7. OCC. 7f. Arbuckle AOI Wells - D Reported Volumes: at ftp://ftp.occeweb.com/og_data/dlyd.zip, Accessed 7 June 7 OGS. 7. Oklahoma Geological Survey (OGS) Earthquake Catalogs: http://wichita.ogs.ou.edu/eq/catalog/complete/complete.csv, Accessed June 7.