The epicentre of the tremor, which occurred at 8. 45 am, was located 1,014 kilometres east northeast of Port Louis, Mauritius, said the US Geological Survey.
The reading was based on the open-ended Moment Magnitude scale, now used by US seismologists, which measures the area of the fault that ruptured and the total energy released.
(Published 12 October 2009, 05:35 IST)