Two years ago, on 28 September 2018, a shallow, large earthquake struck in the neck of Sulawesi Island, Indonesia, with its epicentre located in the mountainous Donggala Regency, Central Sulawesi.
The magnitude 7.5 quake was located 70 km (43 mi) away from the provincial capital Palu and was felt as far away as Samarinda on East Kalimantan and also in Tawau, Malaysia.
This event was preceded by a sequence of foreshocks, the largest of which was a magnitude 6.1 tremor that occurred earlier that day. Following the mainshock, a tsunami alert was issued for the nearby Makassar Strait.
A localised tsunami struck Palu, sweeping shore-lying houses and buildings on its way. The combined effects of the earthquake and tsunami led to the deaths of an estimated 4,340 people.
This makes it the deadliest earthquake to strike the country since the 2006 Yogyakarta earthquake, as well as the deadliest earthquake worldwide in 2018, surpassing the previous earthquake that struck Lombok a few months earlier, killing more than 500.
The Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) confirmed that a tsunami had been triggered, with its height reaching an estimated maximum of 4 to 7 metres (13 to 23 ft), striking the settlements of Palu, Donggala and Mamuju along its path.
The earthquake caused major soil liquefaction in areas in and around Palu. In 4 locations this led to mudflows in which many buildings became submerged causing hundreds of deaths with many more missing. The liquefaction was considered to be the largest in the world and was deemed as rare. ***