Among the most significant after-effects of the magnitude 9.0 earthquake which struck off Japan in March 2011 was the explosion (and subsequent damage) which occurred at the Fukushima nuclear power plant. Although the damage at Fukushima was primarily caused by the ensuing tsunami, rather than the earthquake itself, a new study has shown that the March 2011 tremor may have increased the risk of a devastating earthquake closer to the already-damaged nuclear plant.
Aftershocks from the March 2011 Earthquake
The Honshu earthquake was one of the largest on record, rupturing an extensive area of the sea bed and causing significant damage. The scale of the ‘quake was such that it has generated literally hundreds of aftershocks of a magnitude which would qualify them as major tremors in their own right: at the time of writing they continue to be recorded on a regular basis.
This new study, led by Tohoku University’s Professor Dapeng Zhao, looked closely at one of these aftershocks in particular – an M7.0 event which occurred in April 2011 approximately 60km to the south west of the Fukushima plant, at some distance from the original epicenter. This was interpreted as reactivation of an existing crustal fault, a fact borne out, as Professor Zhang told Decoded Science, by a subsequent significant increase in the number of small earthquakes in the area.Decoded Science