This electronic supplement contains figures of array correlation detection with an alternative embedded event, correlation score as a function of time–bandwidth product, and correlation score using alternative time periods.
Figure S1. The 12 February 2013 explosion at North Korea (DPRK) test site at Punggye-ri (120 s duration short traces) correlated with the 25 May 2009 after it has been transferred to a smaller signal using a transfer function for 2.9t@230 m / 7kt@610 m (proposed yield and depth of the Zhang and Wen [2015] event) embedded in the timeframe of the event reported in Zhang and Wen (2015). The template and stream are filtered between 2 and 8 Hz and are normalized to the maximum amplitude at the array or station, respectively. All detections (circles in SCC traces) are above the 3σ threshold (dashed line), but only the arrays at Ussuriysk, Russian Federation (USRK) has a detection much greater than 3σ. (Station KSRS is located in Wonju, Republic of Korea.)
Figure S2. Correlation score at USRK, where data are for the time period of the Zhang and Wen (2015) event, added to reduced DPRK09, and the template is for DPRK13.
Figure S3. The scaled explosions were embedded in data steams at 75 different times over a one-year time period to explore the detection threshold variability. The median results are shown as large solid dots, and the individual results are shown as small dots. The results for the 12 May 2010 time period are shown as open circles and are the same as in Figure 9. (Z&W10, Zhang and Wen [2015].)
Zhang, M., and L. Wen (2015). Seismological evidence for a low-yield nuclear test on 12 May 2010 in North Korea, Seismol. Res. Lett., 86, doi: 10.1785/02201401170.
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