Indonesia rocked by two big aftershocks: seismologists

Indonesia's Sumatra island was rocked by two powerful aftershocks in the early hours of Tuesday morning, with local tsunami alerts being issued on both occasions, the US Geological Survey said.

A strong 6.7-magnitude aftershock struck at 1:06 am (1806 GMT) at a depth of 35 kilometres (22 miles), 164 kilometres southwest of Sumatra's Padang, the survey said, causing people to wake and flee outside.

Three hours later the same area was rocked again by what appeared to be another aftershock, the USGS said, with that one measured at 6.9 and again 35 kilometres deep.

On both occasions the Hawaii-based Pacific Tsunami Warning Center issued local alerts but there were no initial reports of damage or injuries.

The aftershocks came after a 7.2-magnitude quake struck off the west coast

of Sumatra on Monday afternoon, briefly triggering a tsunami alert, seismologists said, but there were no reports of damage.