Ring of fire: Why Indonesia has so many earthquakes
Indonesia has a deadly and unlucky history with earthquakes.
It is frequently hit, the latest tremor coming 14 years after a 9.1-9.3 magnitude quake off Sumatra prompted a tsunami that left hundreds of thousands of people dead across the Indian Ocean.
The southeast Asian country suffers so much because of its position on a large grid of tectonic plates, on which all the Earth’s countries and seas sit.
Indonesia is at the meeting point of three major continental plates - the Pacific, the Eurasian and the Indo-Australian plates - and the much smaller Philippine plate.
It also falls on the "Ring of fire", a horseshoe-shaped area around the edges of the Pacific Ocean, from Australia to the Andes, along which 90% of all earthquakes occur.
Indonesia’s location makes it particularly vulnerable to earth tremors.
The Earth’s plates grind against each other all the time. Sometimes they get stuck and pressure builds - an earthquake is the sudden and violent release of this pressure.
The archipelago has also been created by its location on the ring, with many of the country’s 17,000 islands forged out of the tectonic and volcanic forces pushing up land, frequently resulting in eruptions or magma and ash.
There are huge swathes of Indonesia where there is always a volcano nearby or on the horizon, and the area is famed for the size of earlier volcanic blasts, with Krakatoa among recent historical incidences.
An example of earthquakes occurring close to a volcano happened in August when a series of quakes rocked the island of Lombok.
The recent quake in Sulawesi caused huge damage because the quake hit close to a high population centre in Palu, and the town was then struck again by a wall of water funnelled down a bay to the sea-level town.
Japan, Turkey, Mexico, Pakistan, Nepal, the Philippines, India and El Salvador are also among the countries most vulnerable to earthquakes