According to the United States Geological Survey, a shallow and moderately strong 5.9 quake struck about 40 kilometres off Sumba, an island of some 750,000 people. It was followed up some 15 minutes later by a stronger 6.0 magnitude quake in the same area at a depth of 30 kilometres.
There were no immediate reports of casualties or damage. Sumba lies some 1,600 kilometres to the south of Sulawesi island which was struck by a devastating quake and tsunami on Friday which killed more than 1000 people.
