The aftershock sequence of the 5 August 2014 Orkney earthquake (M L 5.5), South Africa

摘要: More than 1000 aftershocks were recorded within a month after the occurrence of ML 5.5, 5 August 2014 Orkney earthquake. The events relocated using double difference method as part an effort to identify fault which might be source events. A north–south trend seismicity was revealed by events, with diffuse cluster north main event. depth profile shows these two clusters: one at about 2 km event and other between 3 6 south Focal mechanism solutions 18 determined first motion polarities from seismic stations Council for Geoscience networks. Stress inversion analysis results focal show dominant extensional stress field in region; had strike-slip plane solution. This is consistent regional predominantly related East African rift system. It possible that triggered on shallower faults mining horizons oriented different direction occurred. area has complex heterogeneous faulting structure indicated observed low p values solutions.