1/2500 (0.04%) PGA (cm/s2) calculated based on smoothed seismicity, with recurrence parameters adjusted for the catalogue activity of the corresponding year (overall rate within the WCSB and distribution of events).The black squares denote locations of known clusters of seismic events (most of which are induced) for reference. The shaded regions around Turner Valley encompass the areas contaminated by undistinguished blasts.