Is the Southwest Seismic Zone of Western Australia a fixed zone
The completeness magnitude for earthquakes in Western Australia in the decade prior to the Meckering earthquake is about M3, so the image below shows the progression of earthquakes M>=3 in the subsequent decades. North of Meckering (big purple star at the start of the gif), there is a trend of northeastward migration of seismicity away from Meckering. South of Meckering, the trend is not so obvious but there is still a general sense of migration of seismicity away from Meckering. Note also the fall off of seismicity in the direct vicinity of Meckering.