Another earthquake sounds seismic alarm in Palu

Eight years on from the 2018 disaster, a new 6.7-magnitude tremor has claimed at least one life and caused damage to dozens of homes. It is worth noting that the Central Sulawesi region, situated on the Pacific Ring of Fire, is among the areas in Indonesia most at risk from earthquakes. This has raised questions about the effectiveness of mitigation measures and building inspections.

Jakarta (AsiaNews) – A 6.7-magnitude earthquake that claimed at least one life and caused significant damage yesterday once again turned the spotlight on Palu, the capital of the Indonesian province of Central Sulawesi, which remains one of the areas in Indonesia most at risk from earthquakes.

Yesterday’s event came almost eight years after the devastating earthquake of 28 September 2018, which claimed thousands of lives and triggered a destructive tsunami.

That earthquake had a magnitude of 7.4 and its epicentre was approximately 26 kilometres north of Donggala at a depth of 10 kilometres, triggering a tsunami that swept through Palu Bay and vast coastal areas, making it one of the worst natural disasters in Indonesia’s modern history.

The death toll was made even worse by soil liquefaction, which affected areas such as Petobo, Balaroa and Jono Oge, causing the destruction of entire neighbourhoods.

According to the Indonesian National Disaster Management Agency (BNPB), at least 67 homes were damaged in yesterday’s quake. Among the worst-hit areas is the district of Sigi, where residential buildings, places of worship, bridges, government offices and commercial premises were damaged. In some areas, ground subsidence has cut off the main road linking Palu, Sigi and Poso.

Although it was less powerful than the 2018 earthquake, this latest tremor serves as a significant wake-up call regarding the persistent seismic activity in the area.

According to Daryono, an expert from the Indonesian Association of Disaster Experts (IABI), mitigation strategies need to be updated. In his view, attention should not focus exclusively on the well-known Palu-Koro fault, but also on the numerous active secondary faults present in the region. These include the Sausu, Palolo, Malei, Parigi, Tokararu faults and the Saluki segment.

Experts warn that these fault systems can generate shallow crustal earthquakes, which are particularly dangerous because the energy released reaches the surface rapidly, causing significant damage even at lower magnitudes. The complex local tectonic structure also facilitates the propagation of seismic waves along a network of interconnected faults.

A further risk factor is the phenomenon of ‘stress partitioning’, through which tectonic stresses can trigger secondary fractures outside the main Palu-Koro fault, thereby expanding the areas at risk of damage.

Situated along the so-called Pacific Ring of Fire, one of the world’s most seismically active regions, the island of Sulawesi is influenced by the interaction between the Sunda Plate, the Indo-Australian Plate and the Banda Sea Plate.

Geological studies indicate that the Palu-Koro fault has produced several major earthquakes over the last two thousand years and continues to represent one of the main natural threats to eastern Indonesia. For this reason, experts are calling for more rigorous spatial planning and structural inspections of buildings, with the aim of reducing the risk of future tragedies.