TEMPO.CO, Bandung - According to the Indonesian geological agency, there are two earthquake sources other than the megathrust earthquake in the Sunda Strait that can severely affect Jakarta.
“The two other spots are the active fault in the vicinity of Jakarta and the intraslab underneath Jakarta,” said Sri Hidayati, Head of earthquake mitigation at the Volcanology and Geological Disaster Mitigation Center (PVMBG) on Thursday, March 8.
Sri explained that the closest megathrust earthquake can originate from South Java and the Sunda Strait, which is less than 200 kilometers.
“If a massive magnitude 8 to 9.5 earthquake from those locations occurred, it can devastate Jakarta,” said Sri. The effects of the quake can potentially amplify because of Jakarta’s sedimentary soil basin.
Based on PVMBG’s latest research conducted by its researcher Cipta, Jakarta is composed of quarterly geological sediment. The thickness of the sediment is revealed to be 1,350 meters.
The second quake source is in the intraslab zone, which is where the oceanic crust and the continental crust meet at a depth of more than 90 kilometers. Even though the maximum power is predicted to be lower than a megathrust, it presents dangers of damages to high towering buildings and other types of tall infrastructures, said Sri.
The third source is in the active fault around Jakarta beneath Baribis, Cimandiri, and Citarik. These types of earthquakes are generally less powerful compared to megathrusts or quakes caused by intraslabs earthquake but it can give destructive effects towards buildings due to its shallowness and its close location to land areas, Sri added.
However, the existence of active faults in the vicinity of Jakarta still sparks debates among experts and earthquake researchers. Sri argues that the numerous earthquakes that have hit Jakarta in the past can be considered as a sign of effects of highly amplified earthquakes.