A 7.4 magnitude earthquake triggered a tsunami in Palu, Central Sulawesi, on Friday (September 28th). As of Wednesday (October 3rd), a series of earthquakes continues to accompany the main earthquake, although their magnitude is relatively small.
According to data from the National Disaster Management Agency (BNPB), as of 7:00 a.m. Western Indonesian Time (WIB), there have been 362 aftershocks following the major earthquake that rocked Palu City and Donggala Regency, Central Sulawesi, last week.
Reza Syahputra, a geologist from the Faculty of Mathematics and Natural Sciences, University of Indonesia, explained that the aftershocks that frequently occur after major earthquakes are a normal stabilization process.
He explained that this is due to rock faults seeking equilibrium. Because the faults are large, they stabilize to return to normal.
"Sometimes, if the position of the rocks isn't right, they will always seek equilibrium, which is what causes the tremors," Reza said.
Reza cited the Lombok earthquake as an example, which until recently has been causing relatively small aftershocks.
"This means that if this large-scale rock fault has locked, it's stable, and there are no tremors," he explained.
