As Professor of Earthquake Physics at the University of Ulster, I recently returned from New Zealand where I was a member of an expert panel on future earthquake hazards in the Christchurch area.
We had to assess a number of different models but the basic question was simple: would the current sequence of earthquakes, which included the devastating Christchurch event in February, continue?
Our answer would inform decisions on the earthquake standards to which new structures in the region must be built.
Each of us independently provided our recommendations, so I don’t know what the overall conclusion will be (or would have been before Friday’s earthquake).
However, my view – based on the research I do at Ulster – was that further earthquakes were likely.
At the University, colleagues and I are investigating how the occurrence of one earthquake affects the location and timing of subsequent ones.
In the Christchurch region our work indicates that the September 2010 event triggered the February earthquake, which in turn caused a magnitude 6 event in June.
Collectively, these earthquakes have increased the likelihood of further events in the region.
Friday’s earthquake – which happened just offshore to the North East of the red dots on the map above – appears to have been triggered by the February and June events.
Will there be further earthquakes in the area?
In the short term, the answer is definitely yes as there will be aftershocks of Friday’s event.
I also think in the longer term it’s likely that Christchurch will experience more earthquakes of similar size to the most recent one.