A major magnitude-7.5 earthquake has struck off the Indonesian island of Sulawesi, prompting a tsunami alert hours after a milder quake hit the same area.

Indonesia's meteorology agency issued an early tsunami warning for people in Central Sulawesi and West Sulawesi provinces, asking people to evacuate to higher ground.

The US Geological Survey put the magnitude of the second quake at a strong 7.5, after first saying it was 7.7.

The earlier quake destroyed some houses, killing one person and injuring at least 10, authorities said.

A series of earthquakes in July and August killed nearly 500 people on the holiday island of Lombok, hundreds of kilometres southwest of Sulawesi.

Indonesia sits on the Pacific Ring of Fire and is regularly hit by earthquakes.

In 2004, a big earthquake off the northern Indonesian island of Sumatra triggered a tsunami across the Indian Ocean, killing 226,000 people in 13 countries, including more than 120,000 in Indonesia.

Source: ABC News

BDST: 1737 HRS, SEP 28, 2018

AH