Indonesia has issued a tsunami warning after the powerful and shallow 7.9 magnitude earthquake struck off the west coast of the island of Sumatra.

The quake struck at a depth of 10 kilometres on Wednesday, triggering a tsunami alert for parts of Sumatra, including West Sumatra, North Sumatra and Aceh, the local BMKG quake monitoring agency said.

There were no immediate reports of damage or casualties but the shallower a quake, the more likely it is to cause damage.

The U.S. Geological Survey originally put the magnitude at 8.2, and then 8.1, before lowering it to 7.9.

Indonesia, badly hit by the Indian Ocean tsunami in 2004, straddles the so-called “Pacific Ring of Fire”, a highly seismically active zone where different plates on the earth’s crust meet and create a large number of earthquakes and volcanoes.

The 2004 tsunami killed 230,000 people in a dozen countries. Most of the deaths were in Aceh province.

Source: Agencies