Indonesia's quake and tsunami explained

A tsunami alert has been lifted for the Indian ocean, just hours after two major earthquakes struck Indonesia.

A 8.2 magnitude aftershock came hours after an initial 8.6 magnitude quake struck off the western coast of Aceh.

Later an aftershock in Sumatra sent residents scrambling to get to safety.

There have been no reports of major damage or injuries - and many are crediting local governments for improving their disaster response systems.

The region has been hit hard by tsunamis in recent years.

Al Jazeera's meteorologist Kevin Corriveau explains.