Picking results of an M 0.05 catalogue earthquake (2016/03/14 06:47:46.45). (a) Picking examples; black: raw waveform, blue: STA/LTA trace and red: picked arrival; (b) arrivals of the whole array; (c) clustering result, red: reliable point, black: outlier, green: cluster far away from average arrival time and (d) histogram of reduced arrivals before and after clustering. To be clear, arrivals shown in (c) and (d) have been reduced by the array average.